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Equipment Discussions >> Refractors

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russell23
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CA Reduction filters
      #6113911 - 10/02/13 07:52 PM Attachment (151 downloads)

I have been using a Baader Fringe Killer for several years now with my Vixen 140 NA. Based upon discussions of the use of a #8 light yellow filter for CA reduction and a mention here of the Baader 495 long pass filter I decided to order a 2" Lumicon #8 light yellow and a 2" Baader 495 long pass filter. They are pictured below against a magazine page. Clockwise from top the are the Fringe Killer, Baader 495, and Lumicon #8.

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russell23
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Re: CA Reduction filters new [Re: russell23]
      #6113913 - 10/02/13 07:53 PM Attachment (119 downloads)

Here they are against white index cards with same order as first post if you start on the right side and go counterclockwise:

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Mike4242
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Reged: 11/02/11

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Re: CA Reduction filters new [Re: russell23]
      #6114027 - 10/02/13 08:56 PM

Like you, I've been a huge fan of the Baader Fringe Killer. That filter makes a very noticeable difference in contrast on almost every class of object. I'm very interested to hear how the other filters stack up against the Fringe Killer. I'll be anxiously awaiting your report.

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russell23
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Re: CA Reduction filters new [Re: Mike4242]
      #6114385 - 10/03/13 12:07 AM

Quote:

Like you, I've been a huge fan of the Baader Fringe Killer. That filter makes a very noticeable difference in contrast on almost every class of object. I'm very interested to hear how the other filters stack up against the Fringe Killer. I'll be anxiously awaiting your report.




I just got in from several hours of testing these three filters and my new Agena 18mm dual ED. The first test of the filters was with the 18mm eyepiece and a 3x ES Barlow on Altair (128x). I started with no filter and Altair had a bright, beautiful, purple halo. I then panned west to a small group of fainter stars and found I was unable to get a pinpoint sharp focus of these stars.

With the Fringe Killer the halo around Altair was reduced about 50-60%. The color of Altair was a nice white and when I panned to the group of stars I was able to achieve a nice sharp focus. The 18mm ED has slight edge brightening which was reduced with the Fringe Killer. Sky background was blacker than without the filter and the field seemed "cleaner". All this is what I have always found with the FK.

The #8 light yellow Lumicon performed exactly like the Fringe Killer. Same reduction in CA, same white color or Altair, same increase in pinpoint sharpness of star images. The one thing I noticed was that the Lumicon filter is buttery smooth threading and unthreading whereas both Baader filters are hard to catch initially, then tighten easily, but then are very difficult to unthread. Big advantage to Lumicon here.

Next up was the Baader 495 long-pass filter. This filter cuts 100% of the light below 475nm and let's through over 95% at longer wavelengths. I was extremely impressed with this filter. Altair had zero purple/blue fringing and just a tiny bit of red fringe. Stars were razor sharp at 128x and the mild edge brightening of the 18mm eyepiece was almost completely gone. Altair was a beautiful golden yellow color indicating a strong but not unexpected color shift.

These results were repeated in detail with Vega at 89x.

I then went on to observe number of open clusters, globular clusters, and the nebula M17 and M27. There was no obvious dimming of nebulous light with any of these filters including the longpass. If anything, the increase in sharpness seemed to make fine structure easier to detect with the longpass. Partially resolved clusters such as ngc 6819 and M71were as clear and sharp as I have ever seen them with this scope. Star clusters and the Milky Way were striking with precisely rendered pinpoint sharp stars against a deep black sky.

The color shift with the long-pass filter was not noticeable except on very bright stars. Albireo was yellow-orange and white instead of the natural golden yellow and blue. Fainter stars appeared white.

In short, for deep sky the Baader 495 long-pass was the best filter and I really felt like I was getting the sharpness and contrast of a true APO. The Fringe Killer has never pushed the performance to that level. I just kept thinking "Wow" with that longpass filter!

What I will be interested to see next is how the longpass works with the Moon and Jupiter.

Dave


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Mike4242
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Reged: 11/02/11

Loc: Memphis, TN
Re: CA Reduction filters new [Re: russell23]
      #6114738 - 10/03/13 09:09 AM

Wow! Thanks for that report. Very interesting indeed. I have to admit, I didn't think the yellow #8 would be just as good as the Fringe Killer. The yellow #8 is definitely the most economical way to go. I might have to pick up one of those 495 long-pass filters myself.

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Jon_Doh
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Reged: 09/16/11

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Re: CA Reduction filters new [Re: Mike4242]
      #6114802 - 10/03/13 09:49 AM

Very interesting report. I wonder if stacking a Baader Moon and Skyglow filter with the Longpass would correct the color shift as it does with the Fringe filter?

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russell23
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Re: CA Reduction filters new [Re: Mike4242]
      #6114818 - 10/03/13 10:00 AM

Quote:

Wow! Thanks for that report. Very interesting indeed. I have to admit, I didn't think the yellow #8 would be just as good as the Fringe Killer. The yellow #8 is definitely the most economical way to go. I might have to pick up one of those 495 long-pass filters myself.




Yeah - I came in for the night really excited about the 495 longpass filter. The Fringe Killer is excellent but the 495 longpass takes it to a whole different level.

Last week I found a PDF that gives the transmission data from 400-700nm for all the wratten filters. The #8 is as follows:

<460nm 0%
460 0.25
470 5.5
480 19.0
490 41.0
500 63.5
510 78.0
520 84.1
530-700 86.5-91.5%

These numbers are a stronger cut than the FK so I was surprised there wasn't much difference.

Lunar/planetary tests will be interesting when I get a chance.

Dave


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Jon_Doh
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Reged: 09/16/11

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Re: CA Reduction filters new [Re: russell23]
      #6114831 - 10/03/13 10:08 AM

Here's another thread about the Longpass filter:

http://www.cloudynights.com/ubbthreads/showflat.php/Number/5047210


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russell23
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Re: CA Reduction filters new [Re: Jon_Doh]
      #6114842 - 10/03/13 10:16 AM

Quote:

Very interesting report. I wonder if stacking a Baader Moon and Skyglow filter with the Longpass would correct the color shift as it does with the Fringe filter?




I think it would but for deep sky it will dim the image so I would only stack them for lunar/planetary only.

Dave


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russell23
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Re: CA Reduction filters new [Re: Jon_Doh]
      #6114970 - 10/03/13 11:33 AM

Quote:

Here's another thread about the Longpass filter:

http://www.cloudynights.com/ubbthreads/showflat.php/Number/5047210




That was the thread that led me to try the 495 longpass. Notice in the pictures that the Semi APO shows a fair amount of false color but the 495 shows none. That is what I saw visually last night and the photos in that thread capture the visual difference pretty closely.

Dave


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Mike4242
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Reged: 11/02/11

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Re: CA Reduction filters new [Re: russell23]
      #6115022 - 10/03/13 12:03 PM

Have you ever tried the Contrast Booster?

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Jon_Doh
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Reged: 09/16/11

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Re: CA Reduction filters new [Re: Mike4242]
      #6115043 - 10/03/13 12:17 PM

A little off topic, but for folks sensitive to CA, here are a couple of articles where CA was reported in the ES 127 ED:

http://explorescientific.com/telescopes/ES127Review_v1.pdf
http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/4873424/page...

I wonder if it is necessary to use a Fringe or Long Pass filter with the ED scope?


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Niklo
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Reged: 03/29/13

Loc: Bavaria
Re: CA Reduction filters new [Re: Jon_Doh]
      #6115280 - 10/03/13 02:09 PM

Hi,
today I tried Jupiter without filter and with the fringe killer with my 4" 1100mm achromat.
http://www.cloudynights.com/photopost/showphoto.php?photo=28394&size=big&...
and with the fringe killer please see here:
http://www.cloudynights.com/photopost/showphoto.php?photo=28396&size=big&...
Clear skies,
Roland

Edited by Niklo (10/03/13 02:10 PM)


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Mike4242
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Reged: 11/02/11

Loc: Memphis, TN
Re: CA Reduction filters new [Re: Niklo]
      #6115348 - 10/03/13 02:46 PM

The fringe killer photo appears to have better contrast.

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Mike4242
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Re: CA Reduction filters new [Re: Mike4242]
      #6115376 - 10/03/13 02:58 PM

Looking at the contrast booster transmission graph, it looks like it cuts very slightly deeper into the blue/violet end of the spectrum than the 495 long pass. Also, the contrast booster has a sharp cutoff in the red at about 700nm and cut's some of the green, whereas the 495 long pass doesn't cut any of the spectrum in red or green wavelengths. Not sure what the difference would be in practice. Now we need a comparo between those two filters.

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Jon_Doh
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Reged: 09/16/11

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Re: CA Reduction filters new [Re: Mike4242]
      #6115380 - 10/03/13 03:01 PM

The disadvantage to the contrast booster is that it dims the image a lot more than the long pass or fringe filter. But does a good job on the CA otherwise.

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Niklo
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Loc: Bavaria
Re: CA Reduction filters new [Re: Mike4242]
      #6115411 - 10/03/13 03:12 PM

Quote:

The fringe killer photo appears to have better contrast.



Yes, it improves the contrast and reduces/removes the fringe. The only disadvantage is that the view gets a little bit yellow.
Clear skies,
Roland


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Jon_Doh
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Reged: 09/16/11

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Re: CA Reduction filters new [Re: Niklo]
      #6115417 - 10/03/13 03:15 PM

Quote:

Quote:

The fringe killer photo appears to have better contrast.



Yes, it improves the contrast (planetary detail) and reduces/removes the fringe. The only disadvantage is that the view gets a little bit yellow.
Clear skies,
Roland




Combining it with a Skyglow filter will increase contrast while restoring the color by removing the yellow cast.


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PeterR280
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Re: CA Reduction filters new [Re: Niklo]
      #6115424 - 10/03/13 03:17 PM

I don't see much fringing on the non-filtered image. The colors are more natural. i never liked the greenish yellow tint of the frings killer.

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azure1961p
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Re: CA Reduction filters new [Re: PeterR280]
      #6115450 - 10/03/13 03:34 PM

The white , or rather yellow elephant in the room with the Baader long pass is that strong yellow. I find the Fringe Killer is all the yellow I want on generalized targets before color shift begins to attenuate contrasts. That much yellow on Jupiter or terrestrial spotting or Saturn for that matter might be more hinderance than help. I'm impressed with the long pass on stars but I couldn't see carrying the baggage of that yellow on much else unless it waS to increase something like festoons in Jupiter or other bluer features.

Interesting filter though. I may get the Long Pass - just for limited use however. I'd be curious how it stacks with my Wratten 15 .

Pete

Edited by azure1961p (10/03/13 03:39 PM)


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skywatcher101
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Re: CA Reduction filters new [Re: azure1961p]
      #6115487 - 10/03/13 03:53 PM

Any test using the 495 long pass and a moon and skyglow filter to see if it brings out a more natural color?

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Jon_Doh
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Reged: 09/16/11

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Re: CA Reduction filters new [Re: azure1961p]
      #6115548 - 10/03/13 04:11 PM

The photos in the link I posted above clearly show astrophotography can be done with an achro and that the Longpass filter will remove all of the CA. The photos in that link show CA left with a semi apo filter, but none with the Longpass.

Skywatcher, I'm interested in that kind of test too. It would seem that it would help remove the yellow cast and be very useful on Jupiter. Curious too whether the combo would dim the viewing for stars too much.


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mikey cee
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Re: CA Reduction filters new [Re: azure1961p]
      #6115726 - 10/03/13 05:29 PM

Visually on a white surface that Longpass filter is a dead ringer for my Contrast Booster when compared with my #8 yellow. Has anyone checked the band pass characteristics between those two yet? They are probably different in some small insignificant way for us visuals but it still will turn the planets yellow just the same. No free lunch that's for sure. Mike

Edited by mikey cee (10/03/13 05:52 PM)


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russell23
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Re: CA Reduction filters new [Re: mikey cee]
      #6115896 - 10/03/13 07:05 PM

Quote:

Visually on a white surface that Longpass filter is a dead ringer for my Contrast Booster when compared with my #8 yellow. Has anyone checked the band pass characteristics between those two yet? They are probably different in some small insignificant way for us visuals but it still will turn the planets yellow just the same. No free lunch that's for sure. Mike




If you go to the Agena website both the longpass and the contrast booster transmission curves are published. The CB removes a lot of light that the 495 longpass let's through and would probably cause significant dimming - but might be better in light polluted areas.

Dave


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russell23
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Re: CA Reduction filters new [Re: azure1961p]
      #6115901 - 10/03/13 07:08 PM

Quote:

The white , or rather yellow elephant in the room with the Baader long pass is that strong yellow. I find the Fringe Killer is all the yellow I want on generalized targets before color shift begins to attenuate contrasts. That much yellow on Jupiter or terrestrial spotting or Saturn for that matter might be more hinderance than help. I'm impressed with the long pass on stars but I couldn't see carrying the baggage of that yellow on much else unless it waS to increase something like festoons in Jupiter or other bluer features.

Interesting filter though. I may get the Long Pass - just for limited use however. I'd be curious how it stacks with my Wratten 15 .

Pete




I suspect I may find the color shift a bit much for lunar/planetary, but for deep sky it seems to turn my scope into an APO-like performer.

Dave


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skywatcher101
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Re: CA Reduction filters new [Re: russell23]
      #6118666 - 10/05/13 09:19 AM

Just checking in. Still has anyone stacked a moon and skyglow with the #8 or the 495 long pass ?

Just curious if it keeps the contrast and brings a more "natural" color.

Thanks


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Jon_Doh
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Reged: 09/16/11

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Re: CA Reduction filters new [Re: skywatcher101]
      #6118719 - 10/05/13 09:57 AM

Quote:

Just checking in. Still has anyone stacked a moon and skyglow with the #8 or the 495 long pass ?

Just curious if it keeps the contrast and brings a more "natural" color.

Thanks




I would like to know the answer to that too.


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skywatcher101
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Re: CA Reduction filters new [Re: Jon_Doh]
      #6118939 - 10/05/13 12:16 PM

Jon Doh.....yes interested indeed. I am trying to deside between a #8 or the 495 long pass and using a moon and skyglow.

Another question here is the moon and skyglow filter.....looking at the zhumell urban sky filter is it is comparable to the baader moon and skyglow.

Wondering if the baader is worth the 3x the cost to the zhumell. Anyone capare these two?


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Jon_Doh
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Re: CA Reduction filters new [Re: skywatcher101]
      #6119129 - 10/05/13 02:41 PM

All the Zhumell filters are reasonably priced, but I have no experience with them. I do have the Baader Skyglow and the Zhumell can't be any worse as the Baader by itself doesn't do very much.

In looking at what light these filters cut and what light they allow it would seem, at least on paper, that the Skyglow and Longpass would be a good match. CA would be eliminated and stars would be very close to their natural colors.


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skywatcher101
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Re: CA Reduction filters new [Re: Jon_Doh]
      #6119494 - 10/05/13 07:16 PM

( Jon Doh ) This is my thought as well. Think I may just get the long pass and the Zhumell filter combo.

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Niklo
sage


Reged: 03/29/13

Loc: Bavaria
Re: CA Reduction filters new [Re: skywatcher101]
      #6119575 - 10/05/13 08:23 PM

I'm curious how the yellow longpass filter of Baader performs compared to the fringe killer. It's probably darker. That could help to remove more purple but that could be bad for a 4" achromat because the view get's too dark.
I have a light yellow, filter, a fringekiller and a skyglow filter and a minus violet filter which has the least yellow but so far I haven't done a test series.
Clear skies,
Roland


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russell23
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Re: CA Reduction filters new [Re: Niklo]
      #6119685 - 10/05/13 09:46 PM

Quote:

I'm curious how the yellow longpass filter of Baader performs compared to the fringe killer. It's probably darker. That could help to remove more purple but that could be bad for a 4" achromat because the view get's too dark.
I have a light yellow, filter, a fringekiller and a skyglow filter and a minus violet filter which has the least yellow but so far I haven't done a test series.
Clear skies,
Roland




Roland,

As I summarized, the Fringe Killer knocks down the CA ~50-60% whereas the 495 longpass wipes it out on the blue end (I saw no CA on Vega and Altair with the 495 longpass) and leaves the faintest red CA.

For deep sky I did not see a dimmer view with the 495 longpass. If anything, it was even easier to pick out fine details and faint stars because of the increased sharpness that came with the elimination of the violet CA.

Vega and Altair looked white with a deeper purple fringe with the Fringe Killer and a beautiful golden yellow with the 495 longpass. For deep sky the color shift is of no real consequence, but I haven't yet had a chance to use the longpass for lunar/planetary yet so I will report back when I see how it does there.
Dave


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De Lorme
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Re: CA Reduction filters new [Re: russell23]
      #6120021 - 10/06/13 03:24 AM

Dave, What you said about the long pass filter is exactly
what I saw tonight! Even though the weather was bad{so I was only looking at open clusters }m29 and m39 looked very much improved. Stars were pinpoints of light. But what really amazed me was when I turned the CR6" on the Double
Cluster. The back ground sky was much blacker and the stars
were pinpoints of bright light;really good.
Thanks for going through the trouble of checking these filters out! I'm like you and others here, what's it going to be like on the Moon and Jupiter? I can handle a color
change if I get better contrast and clarity.
I'm going to wait on the Fringe Killer and Moon and Sky Glow
combination{ their not cheap like the Longpass} until I hear from others how the LongPass compares
to them on the Moon and Jupiter. This is a real improvement. Thanks again.
De Lorme


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Niklo
sage


Reged: 03/29/13

Loc: Bavaria
Re: CA Reduction filters new [Re: De Lorme]
      #6120075 - 10/06/13 05:29 AM

Hello De Lorme,
I tried the fringe killer on Jupiter and it removes the small purple fringe in my 4" f/11 but even the fringe killer makes a light yellow view on Jupiter. The contrast improves only a little bit. I think the more CA a refractor has the more helps the fringe killer or even the longpass. In my Vixen 80L f/15 the fringe killer is too much (I haven't tested it yet) and for a 6" f/8 a yellow longpass might be better than the fringe killer. That are my expectations. But I'm curious to hear your reports.
By the way is it the BA2458301 for 1,25 "?
I found it e.g. at
http://www.teleskop-express.de/shop/product_info.php/language/en/info/p521_Ba...
That's quite cheep so I can buy and test it. If it's too much the costs do not harm.
Clear skies,
Roland


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De Lorme
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Re: CA Reduction filters new [Re: Niklo]
      #6120766 - 10/06/13 03:01 PM

Hi Roland, The BA2458301 is the Baader LongPass filter.
Really worth the price! I suspect that what Tommy5{under Filters Against Chromatic Aberration For Achromats} said
"even if you can't see ca, it is still smearing away low contrast planetary detail" is true. I'm waiting to see {reviews}if the Moon and Sky Glow{or some other filter}coupled with the LongPass will give better detail,contrast while taking away the yellow tint.
Does anybody know what combination will work?
Thanks for the info. De Lorme LONG LIVE CLOUDY NIGHTS!


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russell23
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Re: CA Reduction filters new [Re: De Lorme]
      #6125729 - 10/08/13 07:35 PM

I just got in from a quick comparison of the Fringe Killer, #8 light yellow, and Baader 495 longpass on the Moon. The scope is my Vixen 140 Neo-achro. I used a 2.4x Dakin barlow and a 20mm ES68 so the magnification was ~96x.

The sky was not fully dark and the Moon is still low to the horizon so this was not the best conditions because of some turbulence near the horizon.

But as with the deep sky last week the Baader Fringe Killer and #8 light yellow had essentially identical performance. There was a residual purple fringe on the Moon's limb and some hints of CA on the disk. The color of the Moon was not yellow, but still a natural grayish-white with these two filters.

With the 495 longpass the Moon was yellow, but lunar features were sharper and ther was no purple fringe at all - just some faint traces of red CA - which I noted on the stars the other night.

Dave


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azure1961p
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Re: CA Reduction filters new [Re: russell23]
      #6126018 - 10/08/13 10:39 PM

I find the #8 wratten far too obtrusive to deny its there while the Fringe Killer lends a warm feel - almost like summertime haze yellowing. I can't see how the wratten 8 wouldn't make the moon anything but yellow.

Pete

Edited by azure1961p (10/08/13 10:39 PM)


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De Lorme
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Re: CA Reduction filters new [Re: azure1961p]
      #6126221 - 10/09/13 12:57 AM

Looking at the Moon{very low in the sky almost setting} tonight with the Longpass and like Dave the yellow was there but not intrusive. What really caught my eye was how
the mountain ranges and craters stood out. A week from now the Moon will be high in the sky for most of the night.
With the weather getting much better I expect it will be great. Looking at Ngc 7009,7088 at almost zenith
with the filter on the stars were pinpoints of light;
so much better. I'm really glad I bought this filter.
I read somewhere the Moon and Sky Glow with the LongPass
took away the yellow on the Moon; is this true? If it is true would it dim the Moon/Jupiter?
Thanks De Lorme


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grzybu
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Reged: 10/09/08

Re: CA Reduction filters new [Re: De Lorme]
      #6126325 - 10/09/13 03:35 AM

If you want to experiment with rather extreme CA removal for Moon you should try Solar Continuum filter. Moon will be green, but sharpness and image stability will be much, much better. It works only for Moon or Sun, because SC filter is quite narrow band compared to FK or other filters. But it makes huge difference in my 4" F/5 achromatic refractor.
To use SC on Jupiter bigger aperture will be needed. I've tried it once with 11" SCT when Jupiter was low and views were great, with much better stability and sharpness.


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russell23
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Re: CA Reduction filters new [Re: azure1961p]
      #6126649 - 10/09/13 10:02 AM

Quote:

I find the #8 wratten far too obtrusive to deny its there while the Fringe Killer lends a warm feel - almost like summertime haze yellowing. I can't see how the wratten 8 wouldn't make the moon anything but yellow.

Pete




I think this is a great example of differences in sensitivity of people's eyes. I assure you that to my eyes when I put the # 8 in the optical chain it performs identically to the Fringe Killer. The moon looked no different to me in color than with the #8 than with the FK. The 495 longpass did give a yellow color. But I absolutely believe you when you say you see a yellow color with the #8. This is just more anecdotal evidence that everyone's eyes are different.

Dave


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azure1961p
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Re: CA Reduction filters new [Re: russell23]
      #6127804 - 10/09/13 08:19 PM

Yeah the W8 is a nice filter don't get me wrong - I keep it in my filter set for a number of different things - even terrestrial spotting on an overcast day - adds snap to contrasts and flatters my photopic sensitivity. The FK is a paler version to me - its s gentler toning.

We can agree both are excellent filters however!!!


Pete


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Re: CA Reduction filters new [Re: azure1961p]
      #6128360 - 10/10/13 04:12 AM

Just wanted to say thanks Russell for the heads up on the Baader Long Pass.
I was out last night with my AT152 and the results were excellent.

Not only did it eliminate ALL false colour on the brighter stars but it also pulled stars into a much tighter focus and revealed more nebulous features.

I thought I'd have a look for the Veil from my semi-light polluted back yard and was able to glimpse it with the 495, nothing without it and obvious with a OIII.

I also have a mild astigmatism in my good eye which has appeared in the last couple of years, I was considering TV dioptrix but the filter even sorted that out as I saw no aberration at all, stars focused to a perfect disc.

I was hoping for good things from the 495 going by some of the opinions in this thread but it went much further than expected.

The moon was setting last night so didn't get a chance but I should have a Moon & Skyglow filter turning up today so will try the two together.

I've never looked through a 6" APO but it's hard to imagine how much better the views would be.


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Re: CA Reduction filters new [Re: Space Dragon]
      #6128585 - 10/10/13 09:10 AM

I see CN members have been busy buying the 495 long pass filters because of this thread. AgenaAstro is out of stock.

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Re: CA Reduction filters new [Re: Space Dragon]
      #6129705 - 10/10/13 07:03 PM

Quote:

Just wanted to say thanks Russell for the heads up on the Baader Long Pass.
I was out last night with my AT152 and the results were excellent.

Not only did it eliminate ALL false colour on the brighter stars but it also pulled stars into a much tighter focus and revealed more nebulous features.

I thought I'd have a look for the Veil from my semi-light polluted back yard and was able to glimpse it with the 495, nothing without it and obvious with a OIII.

I also have a mild astigmatism in my good eye which has appeared in the last couple of years, I was considering TV dioptrix but the filter even sorted that out as I saw no aberration at all, stars focused to a perfect disc.

I was hoping for good things from the 495 going by some of the opinions in this thread but it went much further than expected.

The moon was setting last night so didn't get a chance but I should have a Moon & Skyglow filter turning up today so will try the two together.

I've never looked through a 6" APO but it's hard to imagine how much better the views would be.




I'm really glad to hear it works well with the 6" achromat too. Thanks for sharing what you found. I continue to be impressed with this filter. Your last sentiment is how I feel about it. With the Fringe Killer I saw important gains in performance, but the 495 longpass makes my Vixen 140NA seem high definition as compared with the view with the FK.

Dave


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Re: CA Reduction filters new [Re: Mike4242]
      #6129725 - 10/10/13 07:22 PM

Quote:

I see CN members have been busy buying the 495 long pass filters because of this thread. AgenaAstro is out of stock.




Looks like Opt is out of the 2" version as well.

Dave


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Mike4242
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Re: CA Reduction filters new [Re: russell23]
      #6129761 - 10/10/13 07:45 PM

They should give you a cut of the proceeds.

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mdowns
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Re: CA Reduction filters new [Re: Mike4242]
      #6129974 - 10/10/13 09:54 PM

Adorama has them,just ordered one.

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De Lorme
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Re: CA Reduction filters new [Re: mdowns]
      #6130083 - 10/10/13 10:43 PM

I got mine from Amazon.

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mdowns
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Re: CA Reduction filters new [Re: mdowns]
      #6131814 - 10/11/13 07:26 PM

I just checked my email for today tonight.Turns out adorama is also out of stock on this one(email notice from them this am). Oh well,dont really mind waiting........

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Re: CA Reduction filters new [Re: mdowns]
      #6132178 - 10/11/13 10:54 PM

I had an opportunity to try the FK, #8, and 495 Longpass on the Moon tonight. Normally I use a 107mm Aperture mask with the Vixen 140 NA, but tonight I used it at full aperture.

As with the other tests, the FK and the #8 were pretty much identical in performance. The Moon to my eyes appeared a nice natural color with those filters. As with previous nights, the #8 did not give any yellowish cast to the Moon - again to my eyes. CA was significantly reduced to a very small fringe at 140x on the limb and also faintly detected in places across the surface. The extent of the purple fringe was essentially the same in both filters. If anything the FK had a tiny bit more CA than the #8.

The 495 longpass completely cleaned up the purple fringe. As on previous nights both on the Moon and on bright stars I did see flickering traces of red CA at the Moon's limb - but not in the form of a halo - just little flashes of narrow red light. There was no doubt that the Moon's features were sharper with the 495 Longpass. The yellow color is strong on the Moon with this filter, but easy to get used to.

One other thing I noticed: My 2x and 3x ES barlows - while great for deep sky and sharp for lunar observations, have not been great for lunar observations because of a brownish light or glare when observing the Moon. With the 495 longpass filter this glare was removed and I had some excellent crisp lunar views when I used the 2x ES barlow with my 28mm Meade RG Ortho and the 2" 2.4x Dakin barlow in front of the diagonal (~140x).

Dave


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De Lorme
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Re: CA Reduction filters new [Re: russell23]
      #6132208 - 10/11/13 11:16 PM

This is really exciting to see such great improvements. I can't wait to try the Moon and Sky Glow with the LongPass on the Moon.
De Lorme


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Re: CA Reduction filters new [Re: De Lorme]
      #6132513 - 10/12/13 06:23 AM

Just got in from an early morning observing session. The 495 longpass really does the job. I was able to get sharp views of Jupiter at 200x with my Vixen 140NA without an aperture mask. That NEVER happens with this scope - even when using the Baader FK and an aperture mask.

As with the earlier observations of the Moon, I found there was some fine red CA.

Dave


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Re: CA Reduction filters new [Re: russell23]
      #6132629 - 10/12/13 09:10 AM

Great report russell. Thanks for continuing to update us on this filter.

DeLorme, I'm looking forward to your report and whether adding a Moon and Skyglow filter adds further enhancements. That combo should restore the color, but I wonder if it also won't help with the red flaring too.


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Re: CA Reduction filters new [Re: Jon_Doh]
      #6132725 - 10/12/13 10:17 AM

I think I might pick up an 82A filter to see what that does for the color.

Dave


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Re: CA Reduction filters new [Re: russell23]
      #6134454 - 10/13/13 08:05 AM

Last night I didn't see any red fringing on the Moon. I also have been spotting faint companions to stars that I had never noticed before. The 495 longpass really is changing the observing experience for the better.

Dave


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De Lorme
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Re: CA Reduction filters new [Re: russell23]
      #6135257 - 10/13/13 03:32 PM

I got the Moon and Sky Glow yesterday so I was able to take a look at the Moon and Vega. M&SG by itself was good but not as good as the Longpass. But coupled with the Longpass it took out the yellow and made it sharper with more contrast.
If you can purchase only one buy the Longpass. Then when you can buy the M&SG.
To me the yellow is very mild. After looking at the Moon for
awhile you hardly see it. But what you do notice are mountain ranges that stand out and Craters that are well defined. When using the M&SG on Vega I would see a little
red on the edge and even less with the Longpass. When
coupled together I saw none but I had to focus carefully.
There were no clouds in the sky yet there seemed to be some
haze. The Moon was just over halfway to setting but still
enough time to get a good look. Vega was pretty high in the sky say around 10 o'clock. Tuesday should be better with the Moon high in the sky and no haze. So patience, patience,
patience. Thanks again Dave. The Longpass really makes a clear difference. I'm going to leave them in my diagonal from now on. De Lorme


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skywatcher101
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Re: CA Reduction filters new [Re: De Lorme]
      #6146611 - 10/19/13 12:25 PM

Got my 495 longpass in mail. Weather not allowing star testing though. I do have a zhumell moon and sky filter, will see how that helps with reducing the yellow.

Paul


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Re: CA Reduction filters new [Re: skywatcher101]
      #6147174 - 10/19/13 05:53 PM

Quote:

Got my 495 longpass in mail. Weather not allowing star testing though. I do have a zhumell moon and sky filter, will see how that helps with reducing the yellow.

Paul




Can't wait to hear what you find with that. I plan to try a light blue 82A filter, but I also am finding the color shift is easy to adjust to. I was doing some daytime testing of a new Barlow the other day and while I could see the color shift it was not as bothersome a one might expect.

Dave


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Re: CA Reduction filters new [Re: russell23]
      #6147394 - 10/19/13 08:21 PM

This is one subject that continues to come up all the time in this forum. Just 2 of the many.
http://alturl.com/56yym

http://alturl.com/b5px3

I guess everyone is looking for the magic C A killer filter. The Badder Long Pass being tops on my list.


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Re: CA Reduction filters new [Re: JimT]
      #6147423 - 10/19/13 08:58 PM

Just rec'd. my Baader Long Pass in the mail. Now, I'd like to order a nice cool, clear night to try it out.

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De Lorme
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Re: CA Reduction filters new [Re: coopman]
      #6147575 - 10/19/13 10:45 PM

Since were having such great results with the Longpass and the Moon & Sky Glow has anybody ever tried any filters with any success with the atmosphere? I just had to ask.
Seek and you shall find. You know the rest. De Lorme


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Re: CA Reduction filters new [Re: De Lorme]
      #6147960 - 10/20/13 07:23 AM

Dave, if you want to try another filter for planetary, the Salmon 85 does VERY well on Mars and actually does pretty well on Jupiter and Saturn too. If you can get used to that strong yellow longpass, you can get used to the salmon tint. This color looks awlful close to the new TV Planetary Contrast filter. Classic achro users have used this filter for years as well. I got mine from HOO made by Hoya, a 2" for $10 I think. Worth every penny. Vernonscope also has them for Brandons. Out of all my filters, the #8 and #85 aren't going anywhere. I even use this filter with my AP 130 GT on Mars to reduce the glare and enhance maria!

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A. Viegas
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Re: CA Reduction filters new [Re: t.r.]
      #6148027 - 10/20/13 08:50 AM Attachment (35 downloads)

Early this morning as dawn was breaking I took a couple of quick pictures through the Hyperion 5mm eyepiece of Sirius with my Istar R30 150mm F8 --

With Sirius Optical MV 20 CA filter, I think this does a very good job. Granted first time using, but still not too bad.



Al


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De Lorme
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Re: CA Reduction filters new [Re: A. Viegas]
      #6148082 - 10/20/13 09:34 AM

Al is the MV 20 any good on the Moon, and Jupiter?
Does it dim the DSO that your looking at?
De Lorme


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A. Viegas
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Re: CA Reduction filters new [Re: De Lorme]
      #6148126 - 10/20/13 10:08 AM Attachment (24 downloads)

I had literally just 10-20 minutes to test it this morning. I did look at Jupiter but honestly I could not really tell much of a difference, except that the MV20 adds some yellow but does get rid of some of the violet haze. Granted these were single Iphone snaps and it was already dawn and I was a bit sleepy so not great -- nevertheless it is what it is... I am not going to have a chance until next week maybe to test it out some more, and next time will definitely try the moon.

Al


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Re: CA Reduction filters new [Re: t.r.]
      #6148250 - 10/20/13 11:28 AM

Quote:

Dave, if you want to try another filter for planetary, the Salmon 85 does VERY well on Mars and actually does pretty well on Jupiter and Saturn too. If you can get used to that strong yellow longpass, you can get used to the salmon tint. This color looks awlful close to the new TV Planetary Contrast filter. Classic achro users have used this filter for years as well. I got mine from HOO made by Hoya, a 2" for $10 I think. Worth every penny. Vernonscope also has them for Brandons. Out of all my filters, the #8 and #85 aren't going anywhere. I even use this filter with my AP 130 GT on Mars to reduce the glare and enhance maria!




Good suggestion. It looks like Vernonscope is the place to get an 85 salmon filter. They have a simple adapter that will allow it to thread into standard thread eyepieces.

Dave


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oldtimer
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Re: CA Reduction filters new [Re: russell23]
      #6150040 - 10/21/13 03:09 PM

Several folks on this thred have mentioned that people have different tollerances to CA. Of course this is true but it also it is true that differnt aperatures and f ratios will produce different levels of CA.

A Lumicon MV filter with a 495nm cutoff works well with my 80mm F7.5 but I need my Semi Apo or #8 yellow for my 127mm F6.5


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Re: CA Reduction filters new [Re: oldtimer]
      #6152140 - 10/22/13 06:10 PM Attachment (41 downloads)

A few photos taken with my I-pad with the Vixen140 at 40x using a 20mm ES68. First ... No filter:

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Re: CA Reduction filters new [Re: russell23]
      #6152144 - 10/22/13 06:10 PM Attachment (34 downloads)

Next with #8 light yellow:

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Re: CA Reduction filters new [Re: russell23]
      #6152147 - 10/22/13 06:11 PM Attachment (40 downloads)

Fringe killer:

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Re: CA Reduction filters new [Re: russell23]
      #6152149 - 10/22/13 06:12 PM Attachment (43 downloads)

Baader 495 longpass filter:

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t.r.
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Re: CA Reduction filters new [Re: russell23]
      #6153102 - 10/23/13 08:10 AM

EGADS!!! How do you stand that longpass tint?!?!
I do see how it sharpens things up though.

It looks like I'm gonna have to try the fringe killer. Thanks for the pic comparison...speaks volumes, at least in daylight.


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skywatcher101
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Re: CA Reduction filters new [Re: t.r.]
      #6153126 - 10/23/13 08:28 AM

Nice comparison between the filters. I have the 495 longpass and I will be getting a yellow #8 sometime soon.

Paul


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skywatcher101
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Re: CA Reduction filters new [Re: skywatcher101]
      #6153134 - 10/23/13 08:32 AM

@ressell23, if you have a moon and skyglow filter, can you stack it and show the results?

Paul


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Re: CA Reduction filters new [Re: skywatcher101]
      #6153297 - 10/23/13 10:01 AM

Quote:

@ressell23, if you have a moon and skyglow filter, can you stack it and show the results?

Paul




I'm planning to get an 82A filter to see what that does to reduce the color shift. I don't have he M&SG.

Dave


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Re: CA Reduction filters new [Re: russell23]
      #6153317 - 10/23/13 10:08 AM

I like the results the Baader Fringe filter stacked with the Baader Moon and Skyglow gives. CA is removed on all but the brightest objects, color is close to normal and sharpness and contrast are vastly improved. The CA that's left on the brightest objects isn't much more than what you see in the ES triplet and that's acceptable to me.

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Re: CA Reduction filters new [Re: t.r.]
      #6153330 - 10/23/13 10:16 AM

Quote:

EGADS!!! How do you stand that longpass tint?!?!
I do see how it sharpens things up though.

It looks like I'm gonna have to try the fringe killer. Thanks for the pic comparison...speaks volumes, at least in daylight.




With the longpass filter the moon is yellow and bright stars like Vega are yellow - but a bright golden yellow Vega is a very pretty. The CA with his filter is gone. The improvement in sharpness is very dramatic for deep sky - better than the Fringe Killer. I have some photos at 100x I will post that illustrate how much better the longpass is than the others.

Dave


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Re: CA Reduction filters new [Re: russell23]
      #6153331 - 10/23/13 10:17 AM Attachment (38 downloads)

Vixen 140 at 100x with no filter:

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Re: CA Reduction filters new [Re: russell23]
      #6153340 - 10/23/13 10:19 AM Attachment (26 downloads)

With #8 wratten:

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Re: CA Reduction filters new [Re: russell23]
      #6153358 - 10/23/13 10:26 AM Attachment (33 downloads)

Baader Fringe Killer:

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Re: CA Reduction filters new [Re: russell23]
      #6153363 - 10/23/13 10:28 AM Attachment (52 downloads)

Baader 495 Longpass:

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Jon_Doh
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Re: CA Reduction filters new [Re: russell23]
      #6153640 - 10/23/13 12:53 PM

The Longpass does much better on a dark sky. Photos taken don't show any CA or color cast that I can tell.

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t.r.
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Re: CA Reduction filters new [Re: Jon_Doh]
      #6153657 - 10/23/13 01:05 PM

The last set of pics remind me of something...imaging is WAY LESS forgiving of CA than the eye alone, so to help put things in a visual only perspective, the first set of pics at 40x illustrates the CA I see visually at about the 150 to 200x range in my C102GT at f/10 with the #8 yellow filter. The second set of pics is really bad...way more than one would see with a filter IMHO. Maybe Dave can expand on what he sees visually with the same scope the pics are taken with...its gotta be less visually!

Edited by t.r. (10/23/13 02:21 PM)


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russell23
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Re: CA Reduction filters new [Re: t.r.]
      #6153851 - 10/23/13 02:46 PM

Quote:

The last set of pics remind me of something...imaging is WAY LESS forgiving of CA than the eye alone, so to help put things in a visual only perspective, the first set of pics at 40x illustrates the CA I see visually at about the 150 to 200x range in my C102GT at f/10 with the #8 yellow filter. The second set of pics is really bad...way more than one would see with a filter IMHO. Maybe Dave can expand on what he sees visually with the same scope the pics are taken with...its gotta be less visually!




The last set of pictures illustrates the relative performance of the scope and filters. The #8 and FK have virtually identical CA reduction performance and the violet fringe is completely removed with the longpass filter but with the noticeable color shift. I think the levels of CA in the photos are similar to what is seen on the brightest stars. The FK removes ~50-60% of the purple fringe on Vega whereas the longpass eliminates the purple fringe on Vega.

Dave


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russell23
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Re: CA Reduction filters new [Re: Jon_Doh]
      #6153857 - 10/23/13 02:48 PM

Quote:

The Longpass does much better on a dark sky. Photos taken don't show any CA or color cast that I can tell.




You are right. For deep sky you won't notice the color shift, but will notice the APO-like pinpoint precision of the stars and the much improved contrast.

Dave


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t.r.
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Re: CA Reduction filters new [Re: russell23]
      #6153869 - 10/23/13 02:55 PM

Is the longpass basically a #12 Wratten? If not, how does it differ?

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russell23
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Re: CA Reduction filters new [Re: t.r.]
      #6153914 - 10/23/13 03:18 PM

Quote:

Is the longpass basically a #12 Wratten? If not, how does it differ?




That's next on my list. I'm ordering a #12 wratten. But the odd thing about it is the published transmission curve of the longpass is that it seems to match the #8 published curves pretty closely, but it doesn't perform at all like the #8. If the published data is to be trusted it looks like this:

#8

400-460-0%
470-5.5%
480-19%
490-41%
500-63.5%
510-78%
520-700-84-92%

#12

400-490-0%
500-1.5%
510-17.3%
520-55%
530-78%
540-700-86-91%

495 longpass

400-470-0%
475-5%
490-80%
500-85%
510-90%
520-700-95%

Dave


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t.r.
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Re: CA Reduction filters new [Re: russell23]
      #6153920 - 10/23/13 03:21 PM

Wow! Thanks for that. The longpass transmits alot more light over a larger range than I thought. Wow!
So the #8 really is the "poor man's" fringe killer...Kudos to D & G for telling me this years ago.


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russell23
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Re: CA Reduction filters new [Re: t.r.]
      #6154042 - 10/23/13 04:29 PM

Quote:

Wow! Thanks for that. The longpass transmits alot more light over a larger range than I thought. Wow!
So the #8 really is the "poor man's" fringe killer...Kudos to D & G for telling me this years ago.




Absolutely correct. I see no discernable difference between the FK and #8 in terms of CA reduction and color shift and contrast/sharpness improvement. I was unprepared for how outstanding the 495 longpass would be on CA elimination.

Dave


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russell23
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Re: CA Reduction filters new [Re: russell23]
      #6156504 - 10/24/13 10:34 PM

I finally got around to ordering the #12 and 82a filters. I will see how the 82a impacts the color shift of the 495 Longpass and compare the CA reduction of the #12 with the longpass. I suspect that unlike the longpass the #12 will cause noticeable dimming.

Dave

BTW, I ordered the filters from Agena and had a shipping notice and tracking number 11 minutes later...wow!


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russell23
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Re: CA Reduction filters new [Re: russell23]
      #6160294 - 10/27/13 08:02 AM

The #12 and 82A filters arrived from Agena yesterday. There were nice clear skies this morning so I took out the scope to compare the #8 and #12 Lumicon filters against the Baader Fringe Killer and 495 Longpass with my Vixen 140 refractor.

First I took a quick look at the Orion Nebula with the 495 Longpass filter and the #12 Lumicon. With the #12 I did notice that the bright stars around the nebula and the stars of the trapezium had a golden yellow color. I noticed this with stars fainter than what I have noticed before with the 495 longpass. So I went back to the longpass and I was able to notice a golden yellow in some of the same stars, but it was not quite as obvious. This seems to fit with the transmission curves.

Next I went to the moon at 96x with my 20mm ES68 and 2" 2.4x Dakin barlow before the star diagonal. For this part I put the filters onto the 2" to 1.25" adapter as I swapped through them.

I went with full aperture instead of using the 107mm aperture mask I made last year.

1. No Filter: Obvious purple fringe and purple wash across the face of the Moon. The surface of the Moon had lavender tint to it and larger craters were fringed with purple glow as well. Nothing about the view could be called crisp.

2. #8 Lumicon Light yellow: The purple fringe was reduced in brightness and extent to only 30-40% of the original amount. Some of the highlands craters still showed some hints of purple fringing but it was now possible to get a nice sharp focus of lunar features. The surface of the Moon now looked to my eyes to be a natural white color as the purple tint was gone.

3. Baader Fringe Killer: Just about identical in performance to the #8 Lumicon. Possibly the Baader has a little better CA removal but I cannot be certain about that. Nice sharp features and same natural white view of the Moon as the #8.

4. Baader 495 Longpass: Purple fringing is completely removed. At first look the Moon appears very yellow. However, as the eyes adjust that backs off perhaps ~50% from the initial impression of the color and the Moon then appears to be a very nice golden yellow - which is how bright stars appear with this filter. Lunar features are definitely sharper than with the #8 and FK. Very crisp lunar craters and fine details across the surface seem to jump out more readily than with the #8/FK.

5. #12 Lumicon yellow: The view with this filter is essentially identical to the 495 long pass. Purple fringing is completely removed. The initial yellow impression with the filter does back off after the eyes adjust - although I think the 495 Longpass backs off a little more - and I also felt with Jupiter and brighter stars that they appeared more yellow with the #12 than the 495 Longpass.

So in summary: The #8 wratten and Baader Fringe Killer are essentially identical in performance reducing CA about 60% visually in my estimation with minimal color shift. In fact, it is possible with these filters that because the Moon showed a purple color with no filter that the net effect of these filters is to bring the color back close to neutral as compared with the unfiltered view. My eyes did not see the color of the Moon as yellow with these filters.

The Baader 495 Longpass and #12 wratten completely remove the purple fringing - its gone with these filters. The views with these two filters are virtually identical. They signifcantly sharpen star images and lunar features. I was able to spot a pinpoint sharp star near the Moon that I did not see in the unfiltered view and didn't notice with the #8/FK. The 495 Longpass and the #12 did cause a yellow color shift that is very obvious on the Moon and bright stars. This color shift seemed stronger with the #12 than the 495 Longpass when looking at brighter stars and Jupiter. On the Moon the difference in color shift was less obvious but still detectable after eyes adjusted.

My personal preference among the 4 filters is the Baader 495 Longpass. I really like the complete CA removal that this filter provides. It sharpens star images for deep sky without any obvious dimming of the view. In fact my deep sky experience on other nights has been that the filter makes it even easier to pick out faint stars in clusters than when using the Fringe Killer. So if it is removing some visible light that is normally focused, then it is a small amount of that light and well compensated for by the increased sharpness that comes with the elimination of all purple CA. I will do a more detailed deep sky comparision between the 495 LP and the #12 on the next clear night - possibly that will be tonight.

Finally, after comparing the filters I went back to the 495 longpass and also put the 1.25" Lumicon #82A filter directly onto the eyepiece. My purpose here was to see if the 82A would shift the color back toward neutral at all. To my eyes the 82A made no difference in color tone of the Moon. However ... I was extremely pleased to find out that the 82A combined with the 495 Longpass gave lunar features a very noticeable extra pop as compared with the 495 alone. I do not believe it was an increase in sharpness because the 495 Longpass provides incredibly sharp views. What the 82A did was make finer Lunar features jump out very clearly - noticeably more so than with just the 495 longpass.

So that is my summary of these filters. Any of these filters provide significant gains on an unfiltered achromat. If you are looking to clean things up to a tolerable level or have a long f/ratio achro then probably the #8 or Fringe Killer will be sufficient. If you are looking for complete CA removal and the sharpest possible views your achro can give - including deep sky - then the 495 Longpass is the best option. The #12 has a little more color shift than the 495 Longpass so that is why I don't rate it equal to the 495 Longpass.

Oh ... I should mention the one drawback to the Baader filters - and this has been a problem with every Baader Filter I have had: 1.25" Semi-apo, 1.25" FK, 2" FK, and now even the 2" 495 Longpass ... the darn threads have a tendency to snag. The last time I put the 495 Longpass on my star diagonal this morning it jammed. From prior experience I know that I will be able to get it off when everything is warmed up, but c'mon Baader - really? Isn't that the oldest part of this equipment? Machining threads? The Lumicon filters are all nice and smooth when they thread. I haven't had a Lumicon filter jam yet.

Dave


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t.r.
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Re: CA Reduction filters new [Re: russell23]
      #6160378 - 10/27/13 09:19 AM

Nice run down on all these...thanks for the work/fun!

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coopman
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Re: CA Reduction filters new [Re: t.r.]
      #6160384 - 10/27/13 09:22 AM

Thanks for all of your efforts on comparing these filters. It was very informative.

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Mike4242
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Re: CA Reduction filters new [Re: coopman]
      #6160418 - 10/27/13 09:50 AM

Thanks for doing that comparison Dave. Very good information there.

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Space Dragon
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Re: CA Reduction filters new [Re: Mike4242]
      #6160438 - 10/27/13 10:07 AM

I've also found that Baader threads tend to bind and also on their T2 accessories.
I now try to avoid threading them completely on or giving them a very small amount of fine oil.
I find they can also be fiddly to get the thread on and have to be careful to avoid cross-threading.
Not great in the dark with cold hands.

Edited by Space Dragon (10/27/13 10:08 AM)


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Re: CA Reduction filters new [Re: russell23]
      #6160474 - 10/27/13 10:28 AM

I have to tell you that after looking at all these pictures, I actually felt that the only "Improvement" was the removal of the fringing, and that the "data" is best presented in the unfiltered views.

I don't seem to see any additional detail with the removal of the fringing.

In fact, in the picture of the trees with leaves taken from a distance, the unfilter view seems to me to present more dynamic range and more detail.

Same with the first branch picture.

The filtered pictures all look very "Flat" by comparisions, as if I am looking though a very lightly frosted glass.

This is why I think of these kinds of filters as being cosmetic.

You remove the fringing, but you don't really put the energy back to where it belongs.

Anyway, that is my own opinion and my own experience. The filters may remove the fringing, but when I tried them, I did not think they really improved my ability to see additional detail.

Anyway, that is what I see when I looked at the pictures. No new detial, and to me, the filtered views all seemed flatter and less contrasty overall than the unfiltere pictures.

First picture of the trees with leaves was the one that I though was the best in terms of the detail I could see in the various colors of the leaves and shading. Band pass picture remnoved the fringing, but left the tree looking kind of flat and dull.

Brances pictures kind of did the same thing to me.

Oh, cosmetically better if the fringe bothers people, but from a raw performace perspective, I don't get it.


Filters cannot refocus energy, They can only take more energy out of the view. The Airy Disk is still reduced by 15% of the energy.


Extended objects still loose their contrast against the background sky.

Filters can't fix these problems.

At lest that is what I see in these pictures.

If people draw their attention away from the fringe and look instead at the details in the picture, I felt like the unfiltered pictures actually seemed to contain the most "Data" and have more range than the filtered views.

Cosmetically, removal of the fringe might be pleasing, but based on these pictures, I can't seem to see that there is any additional detail added.


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russell23
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Re: CA Reduction filters new [Re: Space Dragon]
      #6160837 - 10/27/13 02:16 PM

Quote:

I've also found that Baader threads tend to bind and also on their T2 accessories.
I now try to avoid threading them completely on or giving them a very small amount of fine oil.
I find they can also be fiddly to get the thread on and have to be careful to avoid cross-threading.
Not great in the dark with cold hands.




Ed,

The problem is that the pictures really only are useful for representing the CA removal abilities of the different filters. What you are describing about details you see in these pictures doesn't translate to lunar observations, planetary observations, double star observations, or deep sky observations. I've detailed that in my various posts on this thread and even in what I reported from this morning. I saw far more details on the Lunar surface this morning with the filters than without. The CA blurred away fine details on crater rims and across the lunar surface. Remove the CA and suddenly numerous details are either easier to see or seen that were not seen before.

Same thing when looking at Jupiter. With the Baader Longpass I was able to see sharp views of Jupiter's features at 200x with belt details that are impossible to see without the filter.

I have seen faint companion stars in fields I routinely scan which I had never noticed until I started using the 495 Longpass.

It is impossible to get pinpoint sharp stars above 100x with the Vixen 140 unfiltered. With any of these filters I can easily go to 160x or more and get nice pinpoint sharp stars if the atmosphere allows.

I've noticed more details in partially resolved clusters and even nebula such as M27 with the 495 Longpass.

These are the types of things I am seeing and they are not just cosmetic improvements - they are performance improvements as compared with the unfiltered views. I think it would be worthwhile for you to consider this point: While a filtered 140mm Achromat may not be as good as a TEC 140 APO, a filtered 140mm Achromat IS significantly better than an unfiltered 140mm Achromat. I say this because you keep talking about how the filter can't restore the light not in the airy disk as if that is some argument against the use of a filter with an achromat. It is not. An achromat is what it is and the filters make it better and yes allow the observer to see more details and push the scope to higher magnifications. These filters are not about turning an achromat into an equivalent aperture APO. They are about raising the performance standards of the achro to a higher level.

One thing to keep in mind about the pictures I posted was the day I took those pictures I was dealing with heavy cloudcover and variable amounts of sunlight. That last picture with the Baader Longpass was actually when the sun was getting close to setting and blocked by clouds. Most of the other pictures were taken with brighter sky conditions. If the darn clouds thin out later I will attempt to get some better pictures under more uniform light conditions.

Dave


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t.r.
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Re: CA Reduction filters new [Re: russell23]
      #6160995 - 10/27/13 03:47 PM

Exactly my experiences Dave...perhaps Ed was referring to filter use on SCT's.

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Eddgie
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Re: CA Reduction filters new [Re: russell23]
      #6161145 - 10/27/13 05:35 PM

Well then, I suppose that there must be some value, but I have owned the Vixen 140 and used different filters and never felt like it really made the telescope perform better than some smaller APOs, and for me, the difference was not much different than using simple color filters, which often enhance some details at the expense of others.

You put on this or that filter and this or that detail improves, but this or that other detail would be harder to see.

In a smaller APO though, all of the details were visible without any filter (but even here, some simple color filters can enhance the appearance of some features).

But you have convinced me that you see benefit in it, and that is the most important thing. If you are convinced that there is an improvement, then sharing the result with others is of course the right thing to do.

My advice though would continue to be to always prefer a smaller APO over a larger achromat of any kind. There is to much energy loss in an achromat and no filter made can refocus that energy.

My goal is to get people to avoid thinking that they can approach APO levels of performance simply by buying an achromat and sticking a filter on it and when excellent ED and APOs simply offer much better performance even in less aperture my advice is to go smaller and APO than larger and filter.


But if it improves the performance in any way, then I guess I can't argue the point that it is not worth doing be it expensive bandpass filters, or simple color filters.

I'll keep out of the way of your work to promote these kinds of filters. If there are enough people saying that there is a meaningful improvement, then clearly I am wrong on the topic and I won't distract people from that message any longer..

But I would still suggest that anyone reading this contemplating a big achromat study the topic of encircled energy very closely and consider buying a smaller APO or ED instead.


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A. Viegas
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Re: CA Reduction filters new [Re: Eddgie]
      #6161228 - 10/27/13 06:25 PM

Quote:

My advice though would continue to be to always prefer a smaller APO over a larger achromat of any kind. There is to much energy loss in an achromat and no filter made can refocus that energy.





Really? So you are saying that a 150mm Achromat will produce a less detailed image than an 80mm ED/APO because some of the light is not brought to exact focus? So what is the benefit of larger aperture? Hmmmm... well even the best 80mm APO cannot get you much past 13 magnitude, while 150mm Achromat can easily get to over 14 magnitude. I think you have a better chance of seeing faint DSOs in the larger Achro than the smaller APO and if you want to try and split some tight binaries, certainly the extra aperture helps greatly.

I certainly understand the limitations of the Achro but for those who want to push magnification on the moon or planets the larger aperture trumps the smaller APO, and using filters I suppose can cut down on the annoying fringing. In a perfect world we'd all own AP or Taks...

Al


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De Lorme
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Re: CA Reduction filters new [Re: A. Viegas]
      #6161437 - 10/27/13 08:33 PM

Dave, Did the Moon remain a light yellow with the 82A combined with the Longpass? I thought there would be a shift to the blue. Also did you place the 82A in front or behind the Longpass and would doing either make a differance?
Thanks for the follow up review. De Lorme


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Re: CA Reduction filters new [Re: De Lorme]
      #6161572 - 10/27/13 10:03 PM

Quote:

Dave, Did the Moon remain a light yellow with the 82A combined with the Longpass? I thought there would be a shift to the blue. Also did you place the 82A in front or behind the Longpass and would doing either make a differance?
Thanks for the follow up review. De Lorme




The 82A didn't make any confirmable difference in color. The Moon still looked the same yellow when the 82A was used with the 495 longpass. What the 82A did do was make certain lunar features really stand out in combination with the longpass. The two filters make a great pair in combination for lunar observations.

Dave


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russell23
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Re: CA Reduction filters new [Re: Eddgie]
      #6161646 - 10/27/13 11:01 PM

Quote:

Well then, I suppose that there must be some value, but I have owned the Vixen 140 and used different filters and never felt like it really made the telescope perform better than some smaller APOs, and for me, the difference was not much different than using simple color filters, which often enhance some details at the expense of others.




What filters did you use to try reducing CA? Your review of the Vixen 140NA was in 2004. I've studied this intensively since buying the Vixen 140 several years ago. I was very satisfied with the Baader Fringe Killer but after reading some comments about #8 light yellow and the Baader 495 Longpass I decided to do a comparison. As I'm reporting the 495 Longpass makes a significant difference in image sharpness and the CA is completely removed. The lumicon minus violet filter is probably useless for a large achro because it doesn't cut significantly between 420 and 475nm.

Quote:

You put on this or that filter and this or that detail improves, but this or that other detail would be harder to see.




For what type of observing? I've yet to find anything that did not reveal more detail with the Baader 495 Longpass than without - simply because it is possible to get much sharper focus with the CA removed.

Quote:

My advice though would continue to be to always prefer a smaller APO over a larger achromat of any kind.




When did you change you mind on this? I won't quote from the article directly, but in your 2005 review of the Meade 152mm ED you said that a 102mm APO didn't wow you at all, that you sold your 102mm APO for a 102mm Vixen achro because it was almost as good for a lot less cost. You went on to say that you sold your 4" achro for a Vixen 140NA because the 4" achro just didn't cut it.

Look, people evolve and change their mind about things, but I think your arguments are based upon different experiences. You've not provided any specifics to lead me to believe that you've intensively compared views with and without any of the specific filters I'm using to note if they improve the performance of the achromat.

Quote:

There is to much energy loss in an achromat and no filter made can refocus that energy.




Nobody has said that the filter does refocus the light. I think most people understand that filters of all types remove stuff - be it light of certain colors, or dust particles, or coffee grinds.

Quote:

My goal is to get people to avoid thinking that they can approach APO levels of performance simply by buying an achromat and sticking a filter on it




What aspect of APO performance? My Vixen 140NA is every bit as sharp as my Vixen 80mm f/7.5 fpl-53 ED doublet when I put that 495 longpass filter on it - and it provides a lot more light than the 80mm ED.

Quote:

and when excellent ED and APOs simply offer much better performance even in less aperture my advice is to go smaller and APO than larger and filter.




How much smaller do you think an APO can be and still outperform an achro filtered with a filter that completely removes the CA? The Baader 495 longpass transmits over 90% of the light from 510 nm and longer and actually transmits 95+% of the light from 530nm on. Even if the filtered Vixen 140NA was losing 20% of the light compared with an unfiltered APO (and it is certainly less than that) it would still be performing at the level of a 125mm APO in terms of total light - although the distribution across wavelengths will be different.

But this means to get an APO that actually significantly outperforms a filtered Vixen 140NA you need an APO with a minimum aperture of 140mm and that is where they start to get really expensive.


Quote:

But if it improves the performance in any way, then I guess I can't argue the point that it is not worth doing be it expensive bandpass filters, or simple color filters.

I'll keep out of the way of your work to promote these kinds of filters. If there are enough people saying that there is a meaningful improvement, then clearly I am wrong on the topic and I won't distract people from that message any longer..




You're welcome to make your case. That is what this forum is for. Your point of view on the quality of view you can get from a filtered achromat is just very different than my experience with the filters I've been reporting on.

Quote:

But I would still suggest that anyone reading this contemplating a big achromat study the topic of encircled energy very closely and consider buying a smaller APO or ED instead.




Assuming a Baader 495 longpass that transmits over 90% from 510nm and longer, 80% at 490 nm and zero % of light below 475nm such that there is no CA evident and no loss of sharpness and contrast from CA, what aperture APO do you think would be appropriate to replace a 5.5-6" achro and not provide noticeably less light than the filtered achro. I suggested at a minimum the filtered 140 is providing as much light as a 125mm APO and probably it is closer to a 132mm APO for total light - again without the same wavelength distribution because the 400-470nm wavelengths are completely blocked.

Dave


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De Lorme
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Re: CA Reduction filters new [Re: russell23]
      #6161676 - 10/28/13 12:04 AM

Thanks Dave I'm going to order one. Again thanks for doing
these comparisons. The Longpass really makes a differance.
I cannot wait to try the 82A. De Lorme


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eklf
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Re: CA Reduction filters new [Re: russell23]
      #6161934 - 10/28/13 07:06 AM

Thanks Dave for taking the time to conduct and document the performances of these filters. Your objecive descriptions and clear demarcation of subjective perceptions were very helpful, and overall very informative. I have 127 F6.5 so I am naturally interested in the filter performances. I recently acquired #8, #11,and #12 filters, but havae not had the time to comapare them yet. On a single night's brief comaprison I felt the #11 to offer better performace on the moon compared to #8 (but somewhat dimmer), and siighty better than #12 (but with a somewhat greenish tinge that I found more pleasing than the yellow of #12). If you get a chance pop in a #11 for a different feel.

Thanks again for a well documented and informative sereis fo posts.


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Jon_Doh
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Re: CA Reduction filters new [Re: eklf]
      #6162121 - 10/28/13 09:44 AM

It seems to be that there is a difference between the theoretical science, ie, physics of light scattering/focusing and what the human eye actually sees. And there is a difference in achros, not just from brand to brand, but from telescope to telescope within a brand. I've looked through achros that were so bad no filter was going to make any difference. And I've looked through some that the view was so good you didn't need any filter. That one produced a view that was sharp, contrasty, bright with no discernible CA except on the very brightest stars. Then applying a Fringe Filter stacked with a Deep Sky Filter not only removed the CA, but improved the contrast while rendering a neutral (true) color with no noticeable light loss.

One six inch achro shows significant CA on the moon with a purple field washed across the moon's surface while the other achro of the same aperture and f ratio did not. I didn't have an APO next to the second achro to compare the view, but I did have a larger aperture SCT set up nearby and what this achro produced was every bit as good as the view the SCT showed.

Bottom line, in this dumb football player's humble opinion, based on what he's seen through the eyepiece of a few achro refractors and not understanding physics and math at all when it comes to light I certainly can understand why there are folks in each camp. If you've looked through a bad achro you'll be in Edggie's camp and be convinced no filter is going to do any good. I've seen those and I agree they can't be helped that much. But when you have looked through the eyepiece of a well corrected achro you'll understand their value and why somebody would want to own a big six inch achro.


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t.r.
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Re: CA Reduction filters new [Re: Jon_Doh]
      #6162160 - 10/28/13 10:08 AM

...Or an 8" ...

8"DG vs. 12"Portaball


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Jon_Doh
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Re: CA Reduction filters new [Re: t.r.]
      #6162394 - 10/28/13 12:13 PM

Quote:

...Or an 8" ...

8"DG vs. 12"Portaball





That thing looks like a missile


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Re: CA Reduction filters new [Re: De Lorme]
      #6163305 - 10/28/13 08:40 PM

Quote:

Thanks Dave I'm going to order one. Again thanks for doing
these comparisons. The Longpass really makes a differance.
I cannot wait to try the 82A. De Lorme




Thanks for the positive feedback! I was really surprised by the longpass because I have been very satisfied with the Fringe Killer. For me the longpass has replaced the FK as my filter of choice.

Dave


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russell23
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Re: CA Reduction filters new [Re: eklf]
      #6163313 - 10/28/13 08:45 PM

Quote:

Thanks Dave for taking the time to conduct and document the performances of these filters. Your objecive descriptions and clear demarcation of subjective perceptions were very helpful, and overall very informative. I have 127 F6.5 so I am naturally interested in the filter performances. I recently acquired #8, #11,and #12 filters, but havae not had the time to comapare them yet. On a single night's brief comaprison I felt the #11 to offer better performace on the moon compared to #8 (but somewhat dimmer), and siighty better than #12 (but with a somewhat greenish tinge that I found more pleasing than the yellow of #12). If you get a chance pop in a #11 for a different feel.

Thanks again for a well documented and informative sereis fo posts.




Thank you!

Interesting! I just looked at the transmission curve data for the #11. It has an overall transmission of 40% but let's in a little more light at blue wavelengths. The #8 has 83% transmission overall. Have you had a chance to compare the CA reducing effects of the #11 compared with the other two?

Dave


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russell23
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Re: CA Reduction filters new [Re: Jon_Doh]
      #6163339 - 10/28/13 08:58 PM

Quote:

It seems to be that there is a difference between the theoretical science, ie, physics of light scattering/focusing and what the human eye actually sees. And there is a difference in achros, not just from brand to brand, but from telescope to telescope within a brand. I've looked through achros that were so bad no filter was going to make any difference. And I've looked through some that the view was so good you didn't need any filter. That one produced a view that was sharp, contrasty, bright with no discernible CA except on the very brightest stars. Then applying a Fringe Filter stacked with a Deep Sky Filter not only removed the CA, but improved the contrast while rendering a neutral (true) color with no noticeable light loss.

One six inch achro shows significant CA on the moon with a purple field washed across the moon's surface while the other achro of the same aperture and f ratio did not. I didn't have an APO next to the second achro to compare the view, but I did have a larger aperture SCT set up nearby and what this achro produced was every bit as good as the view the SCT showed.

Bottom line, in this dumb football player's humble opinion, based on what he's seen through the eyepiece of a few achro refractors and not understanding physics and math at all when it comes to light I certainly can understand why there are folks in each camp. If you've looked through a bad achro you'll be in Edggie's camp and be convinced no filter is going to do any good. I've seen those and I agree they can't be helped that much. But when you have looked through the eyepiece of a well corrected achro you'll understand their value and why somebody would want to own a big six inch achro.




Good points! What you are saying reminds me of the recent thread here about respacing the lenses of an achromat to reduce CA. Perhaps with poorly set achromat lenses filters won't lead to much improvement.

With my scope the filters make a huge difference.

Dave


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SimonL
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Re: CA Reduction filters new [Re: russell23]
      #6168422 - 10/31/13 12:44 PM

Do you people use the 1.25" size or 2" version of the longpass filter?

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De Lorme
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Re: CA Reduction filters new [Re: SimonL]
      #6168552 - 10/31/13 01:43 PM

SimonL I use the 1.25 Longpass because it's cheaper.
De Lorme


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saemark30
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Re: CA Reduction filters new [Re: De Lorme]
      #6168709 - 10/31/13 03:19 PM

I guess the OIII filters are the best CA reduction filters around.
Which ones are best? I have seen Lumicon lamination problems with their filters.


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coopman
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Re: CA Reduction filters new [Re: saemark30]
      #6169068 - 10/31/13 06:48 PM

An OIII filter is good for CA reduction? Really?

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MrJones
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Re: CA Reduction filters new [Re: coopman]
      #6170105 - 11/01/13 12:03 PM

I wound up using a Wratten #12 with my AR5 after trying many filters. I only used it on the moon and planets. I was a little surprised to find that I thought the Wratten #12 was better than the #8 at everything other than a more yellow tint - and in particular it got rid of the last little bit of observable violet blue CA for me with this scope. After a little research I found some transmission spectra that support this. Note that from these you can see that the Wratten #12 has a sharper cutoff and higher overall transmission. Something to think about!

Wratten #8

Wratten #12


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azure1961p
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Re: CA Reduction filters new [Re: MrJones]
      #6172673 - 11/02/13 09:56 PM

Trouble with an OIII is its color shift isn't exactly mild and some folks would find it detrimental. Its lousy on Jupiter for example.

Pete


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Re: CA Reduction filters new [Re: azure1961p]
      #6173465 - 11/03/13 10:43 AM

Quote:

Trouble with an OIII is its color shift isn't exactly mild and some folks would find it detrimental. Its lousy on Jupiter for example.

Pete




Not to mention an OIII filter transmits very little visible light. Look at the transmission curve for the Baader OIII on the Agena website. It has a 10 nm transmission width at 500nm wavelength. It is not intended as a CA reduction filter.

Dave


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russell23
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Re: CA Reduction filters new [Re: MrJones]
      #6173474 - 11/03/13 10:49 AM

Quote:

I wound up using a Wratten #12 with my AR5 after trying many filters. I only used it on the moon and planets. I was a little surprised to find that I thought the Wratten #12 was better than the #8 at everything other than a more yellow tint - and in particular it got rid of the last little bit of observable violet blue CA for me with this scope. After a little research I found some transmission spectra that support this. Note that from these you can see that the Wratten #12 has a sharper cutoff and higher overall transmission. Something to think about!

Wratten #8

Wratten #12




Interesting. These transmission curves differ from the document compiled for Eastman Kodak for all Wratten Filters. That document gives an overall transmission of 83% for the #8 and 73% for the #12. That is consistent with my experience with the Lumicon #'s 8 and 12. I took more photos the other day and the #12 eliminated CA like the 495 Longpass but unlike the longpass was darker than the #8.

I wonder how much variation there is.

Dave


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coopman
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Re: CA Reduction filters new [Re: russell23]
      #6173588 - 11/03/13 11:42 AM

I used my Baader longpass filter in the AR152 last night for the first time and was very happy with the improvement that I noticed. Stars were tighter pinpoints and Vega was a bright yellow star with no bluish halo. It did not seem like I was using an achromat any more. The various colors of other stars were still apparent, i.e., the longpass filter did not change all of the stars to yellow ones. This filter may have found a permanent place in my diagonal.

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russell23
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Re: CA Reduction filters new [Re: coopman]
      #6173645 - 11/03/13 12:17 PM

Quote:

I used my Baader longpass filter in the AR152 last night for the first time and was very happy with the improvement that I noticed. Stars were tighter pinpoints and Vega was a bright yellow star with no bluish halo. It did not seem like I was using an achromat any more. The various colors of other stars were still apparent, i.e., the longpass filter did not change all of the stars to yellow ones. This filter may have found a permanent place in my diagonal.




Great! It makes a big difference for sharpness and contrast. To this point in my continuing tests of the #8 light yellow, #12 yellow, Baader Fringe Killer, and Baader 495 Longpass, I find the 495 Longpass to be the best. The #8 and FK improve the contrast and sharpness, but the 495 Longpass eliminates the CA with no significant dimming of the object. The #12 eliminates the CA but causes some definite dimming.

Dave


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Jon_Doh
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Re: CA Reduction filters new [Re: russell23]
      #6173904 - 11/03/13 02:59 PM

I wonder if there is another filter you could combine with the Longpass to restore/correct the color?

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SimonL
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Re: CA Reduction filters new [Re: Jon_Doh]
      #6174189 - 11/03/13 06:04 PM

A 2" size filter can be placed ahead of a 2" diagonal and used from imaging without vignetting.

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SimonL
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Re: CA Reduction filters new [Re: SimonL]
      #6174203 - 11/03/13 06:10 PM

Would you use the Longpass 495 doing imaging?

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russell23
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Re: CA Reduction filters new [Re: Jon_Doh]
      #6174223 - 11/03/13 06:23 PM

Quote:

I wonder if there is another filter you could combine with the Longpass to restore/correct the color?




Not without severely reducing brightness. I used a 82A with the Baader 495 Longpass and there was a barely detectable color shift blueward, but still yellow. For lunar views it did create additional pop for features.

Dave


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Re: CA Reduction filters new [Re: SimonL]
      #6174232 - 11/03/13 06:25 PM

Quote:

Would you use the Longpass 495 doing imaging?




I'm visual only, but with the color shift involved with the Longpass I guess that would depend upon what you are looking for when imaging. Really I would think for imaging a smaller APO would be the better choice.

Dave


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gdd
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Re: CA Reduction filters new [Re: Jon_Doh]
      #6174298 - 11/03/13 07:06 PM

Quote:

I wonder if there is another filter you could combine with the Longpass to restore/correct the color?





The 495 longpass is a yellow filter that works by blocking out the blue end of the spectrum past 495nm. To restore/correct the color you would need to add the blue back in. Filters cannot add color that is not there, and even if it could the added blue would be out of focus and recreate the blue haloes you are trying to remove. The only way to partially correct the color is to replace the 495 longpass with a lighter yellow filter, maybe a Number 8 which passes a bit more of the blue end.

If you were imaging you could use 495 longpass to create the red and green channels of an color image using a DSLR or OSC camera, then use a blue filter by itself to replace the blue channel.

Gale

Edited by gdd (11/03/13 07:13 PM)


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azure1961p
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Re: CA Reduction filters new [Re: coopman]
      #6174786 - 11/04/13 02:01 AM

Well - Vega is not a yellow star by any stretch. Perhaps an effect crested by the filter?

Pete


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Jon_Doh
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Re: CA Reduction filters new [Re: gdd]
      #6175057 - 11/04/13 09:25 AM

The reason I asked is because when you combine a Moon and Skyglow filter with the Fringe Filter it restores color very close to natural. Some CA will still be present on bright objects like Vega, but the result is not as strong as the semi apo, which uses the same concept, but with more filtering and thus greater light loss.

Regardless of the slight color shift I do like how well the Longpass filter works for astrophotography. I haven't seen any CA in photos taken with this filter and the shift in color can easily be corrected in Photoshop. If nothing else, this filter makes astrophotography a reality with an achro.


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russell23
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Re: CA Reduction filters new [Re: Jon_Doh]
      #6175085 - 11/04/13 09:42 AM

Quote:

The reason I asked is because when you combine a Moon and Skyglow filter with the Fringe Filter it restores color very close to natural. Some CA will still be present on bright objects like Vega, but the result is not as strong as the semi apo, which uses the same concept, but with more filtering and thus greater light loss.

Regardless of the slight color shift I do like how well the Longpass filter works for astrophotography. I haven't seen any CA in photos taken with this filter and the shift in color can easily be corrected in Photoshop. If nothing else, this filter makes astrophotography a reality with an achro.




That is true, you can photoshop the colors to restore neutrality and the filter eliminates the CA so you don't have to mess with that. You are right in that sense that the 495 Longpass makes the achro suitable for AP. I guess the one thing that Ed points out that is relevant here is that because the defocused light is not restored any details that the blue wavelengths carry more strongly than other wavelengths would be lost.

From my point of view visually, that lost information is not as critical as the fact that I can see more details with the filter than I can without the filter simply because the image is sharpened up.

Dave


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saemark30
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Re: CA Reduction filters new [Re: azure1961p]
      #6175587 - 11/04/13 02:23 PM

What do you think about a K2 yellow filter?
Is it as good as a #8, stronger or weaker?


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saemark30
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Re: CA Reduction filters new [Re: saemark30]
      #6175612 - 11/04/13 02:32 PM

And a #12 filter looks to behave like the Longpass 495 filter.

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russell23
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Re: CA Reduction filters new [Re: saemark30]
      #6175894 - 11/04/13 05:00 PM

Quote:

And a #12 filter looks to behave like the Longpass 495 filter.




Yes, but the #12 has a visually detectable dimming effect as compared with the 495 Longpass. I've seen this both in daytime pictures and nighttime comparisons of the Moon, Jupiter, and nebulous deep sky objects such as emission nebula and partially resolved star clusters. All of these appear brighter with the 495 Longpass than with the #12.

Dave


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russell23
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Re: CA Reduction filters new [Re: saemark30]
      #6175895 - 11/04/13 05:01 PM

Quote:

What do you think about a K2 yellow filter?
Is it as good as a #8, stronger or weaker?




I've never tried the K2 so I can't say.


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*skyguy*
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Re: CA Reduction filters new [Re: russell23]
      #6181108 - 11/07/13 01:48 PM

I just got my Baader 495 Longpass filter in the mail, today! I can't wait to try it out on several achromatic refractors I own.

However, all the talk about about its suitability for use in astrophotography has me confused ... especially the posts on how the color shift can be easily corrected in Photoshop. Since most of blue end of the spectrum has actually been blocked/removed ...I really don't see how the blue can be restored.

I tried Photoshoping one of posted 495 filtered images and while I could get a reasonably color balanced image, a large part of blue fringing was also restored and now very visible in the image!

If someone would post the work flow in Photoshop detailing the steps to color balance a 495 filtered image ... that would be really great!

Thanks ...


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Jon_Doh
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Re: CA Reduction filters new [Re: *skyguy*]
      #6182374 - 11/08/13 07:33 AM

Go to filter menu, select Lens Correction and check Chromatic Aberration box. This will automatically remove most if not all of the CA. Additional adjustments can be made with the sliders. In Lightroom go to Lens Correction in the Develop Module and check the CA box.

Frankly, with this filter I haven't seen the purple halos you typically see in photos taken with achros. The only adjustment that seems is necessary is removing the yellow cast this filter introduces on bright stars. That's easy to fix in Photoshop or Lightroom too.


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*skyguy*
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Re: CA Reduction filters new [Re: Jon_Doh]
      #6182621 - 11/08/13 10:11 AM

Quote:

Go to filter menu, select Lens Correction and check Chromatic Aberration box. This will automatically remove most if not all of the CA. Additional adjustments can be made with the sliders. In Lightroom go to Lens Correction in the Develop Module and check the CA box.




Thanks ... sounds good ... I'll give it a try!


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*skyguy*
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Re: CA Reduction filters new [Re: *skyguy*]
      #6183072 - 11/08/13 02:23 PM Attachment (25 downloads)

I haven't had the chance to test my 495 Longpass filter on the night-sky ... clouds, clouds and in the near future more clouds!

However, I couldn't resist testing it out in the daytime ... between the rain and snow showers! I used my very inexpensive 70mm f/5.7 (400mm) achromatic refractor and an unmodified Canon DSLR. The test object was an old barn located about 600 feet from the camera. The posted test image shows a 3X enlargement of the corner of the barn's roof with several foreground power lines. Color correction was done in Photoshop (no other processing was done) using only the "Auto Color" and "Auto Tone" buttons ... which elicited from me the very much coveted "Oh, WOW!" exclamation when the processed image was displayed! When compared to the original unfiltered image ... the corrected, filtered image looked like a blue fog had been lifted right off it! This image showed a significant increase in sharpness and contrast over the unfiltered image along with an almost total reduction of chromatic aberration. However, the exposure time of the filtered image did need to be increased from 1/500th of a second to 1/350th of a second to equalize the total exposure between both images. I've become a convert!

I'm looking forward to the opportunity to try this filter out under the stars ... if it ever clears up ... maybe early March!


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Jon_Doh
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Re: CA Reduction filters new [Re: *skyguy*]
      #6183105 - 11/08/13 02:44 PM

Excellent!

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t.r.
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Re: CA Reduction filters new [Re: *skyguy*]
      #6183112 - 11/08/13 02:47 PM

Can't wait to see if a few pics can be passed off as ED doublets or even an apo..who's gonna give it a try?!?!

Edited by t.r. (11/08/13 02:47 PM)


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De Lorme
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Re: CA Reduction filters new [Re: t.r.]
      #6189491 - 11/11/13 09:19 PM

I had about an hour the other night to look at the moon before the clouds rolled in and was comparing the Longpass,
80A and the Moon and Sky Glow. The LongPass was again the real winner. The Moon and Sky Glow wasn't as much a help
as previous reported and the 80A made the Moon dimer.
Because on the web it said if you have 5" or bigger than go
with 80A not the 82A. In trying the M&SG coupled to the Longpass I thought it was worse. I was disappointed because
it's not what I saw the first time I used them together.
I'm going to try the 82A and see what happens. I'm really
glad I bought the Longpass. De Lorme


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B. Cook
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Re: CA Reduction filters new [Re: De Lorme]
      #6189504 - 11/11/13 09:28 PM

I had a heck of a time finding the Baader 495 longpass filters. I finally found the 2 in and 1 1/4 sizes at Adorama. They are now out of the 1 1/4 but they said they still have the 2 in as of today. Thanks

Bill


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Re: CA Reduction filters new [Re: De Lorme]
      #6191206 - 11/12/13 05:28 PM

Quote:

I had about an hour the other night to look at the moon before the clouds rolled in and was comparing the Longpass,
80A and the Moon and Sky Glow. The LongPass was again the real winner. The Moon and Sky Glow wasn't as much a help
as previous reported and the 80A made the Moon dimer.
Because on the web it said if you have 5" or bigger than go
with 80A not the 82A. In trying the M&SG coupled to the Longpass I thought it was worse. I was disappointed because
it's not what I saw the first time I used them together.
I'm going to try the 82A and see what happens. I'm really
glad I bought the Longpass. De Lorme




I think you will like the 82a with the Longpass. I thought it made features really pop.

Dave


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De Lorme
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Re: CA Reduction filters new [Re: russell23]
      #6191334 - 11/12/13 06:38 PM

I just ordered the Lumicon. This is such great fun. The weather is going to be clear tonight so I'll be out looking at the moon. De Lorme

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spongebob@55
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Re: CA Reduction filters new [Re: De Lorme]
      #6199868 - 11/17/13 12:38 PM

I tried the longpass on the moon about a week ago. I wasn't impressed by the results. First, let me say that I was out previously and had tried it on bright stars and was very impressed. It did seem to make the CA almost disappear (using my 102mm f9.8 achromat.) But on the moon, it made hardly any difference on the edge CA and made the moon too yellow for my liking. Now there's hardly any CA with my scope anyway! So I just observed w/o the long pass filter. Next up will be Jupiter, but since I just got a new hip Monday, it might be some time before that happens. Darn it!
Sbob


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De Lorme
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Re: CA Reduction filters new [Re: spongebob@55]
      #6199875 - 11/17/13 12:43 PM

Hang in there Sbob it will get better. De Lorme

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Re: CA Reduction filters new [Re: spongebob@55]
      #6199939 - 11/17/13 01:24 PM Attachment (35 downloads)

Two nights ago, I imaged the moon with and without mt 495 Longpass filter using a $40 dollar 70mm f/5.71 (400mm) achromatic refractor. The moon was still low in the sky .... however, I was interested in just testing the filter, not getting a pretty picture. What I did notice immediately when looking at the moon through the viewfinder with the 495 filter ... the moon was sharper and it was easier to find the perfect focus!

The unfiltered moon image is unprocessed. The only Photoshop processing done on 495 filtered image was AutoColor, AutoTone and a reduction in saturation in the yellow channel to remove some residual yellow color.

Overall, the filter does seem to produce an image with greater contrast and it did a good job of removing chromatic aberrations and restoring lost detail along the edge of the moon. Of course, there is always the possibility that some or all of the increased detail could be the result of better seeing and/or better focus between the two images. However, the 5X blowup of Mare Humboltianum (top and slightly to the right of the posted images) does show the removal of the CA allowing the detail of the mountains along the lunar rim to be revealed. At least that's my take on what is happening.


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*skyguy*
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Re: CA Reduction filters new [Re: *skyguy*]
      #6199941 - 11/17/13 01:25 PM Attachment (33 downloads)

Unfiltered moon image:

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*skyguy*
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Re: CA Reduction filters new [Re: *skyguy*]
      #6199945 - 11/17/13 01:26 PM Attachment (33 downloads)

495 Longpass filtered moon image:

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Rutilus
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Re: CA Reduction filters new [Re: *skyguy*]
      #6199971 - 11/17/13 01:41 PM Attachment (29 downloads)

Out of interest, at what point would we say(i.e. f/10, f/12, f/15 etc.) that the benefit of these filters becomes reduced.
Here are 4 images taken with my 6" f/15. For two of them, I used Baader filters, natural un-filtered and a #12 Yellow filter.


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saemark30
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Re: CA Reduction filters new [Re: Rutilus]
      #6200280 - 11/17/13 04:43 PM

Which is which Rutilus?

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Jon_Doh
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Re: CA Reduction filters new [Re: saemark30]
      #6200395 - 11/17/13 05:58 PM

sBob you'll get better results with your telescope if you stack a Fringe filter with a Moon and Skyglow.

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spongebob@55
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Re: CA Reduction filters new [Re: Jon_Doh]
      #6200787 - 11/17/13 10:11 PM

Quote:

sBob you'll get better results with your telescope if you stack a Fringe filter with a Moon and Skyglow.




Ok, I have both of those. I try it! Perhaps it won't be so yellow? So do you think that this is the combination of filters for just the moon, or also for planets?

Thanks
Bob


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spongebob@55
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Re: CA Reduction filters new [Re: De Lorme]
      #6200796 - 11/17/13 10:20 PM

Quote:

Hang in there Sbob it will get better. De Lorme



Thanks De Lorme. I am already walking around the block, 4 days post surgery. But that's only the 1st step of probably about 100. But overall, I'm quite happy with the 'replacement parts' Now to get my 'observing' muscles back as fast as possible.


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DeSoto Kid
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Re: CA Reduction filters new [Re: spongebob@55]
      #6212612 - 11/24/13 04:44 AM

Quote:

Quote:

sBob you'll get better results with your telescope if you stack a Fringe filter with a Moon and Skyglow.




Ok, I have both of those. I try it! Perhaps it won't be so yellow? So do you think that this is the combination of filters for just the moon, or also for planets?

Thanks
Bob




Bob,
Have you tried the Fringe Filter with the Moon and Skyglow yet? I'm anxious to learn of the result.
Wayne R.


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grzybu
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Reged: 10/09/08

Re: CA Reduction filters new [Re: DeSoto Kid]
      #6212947 - 11/24/13 10:30 AM

I always use Fringe Filter with the Moon and Skyglow. It makes image less yellow and more stable.

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CollinofAlabama
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Re: CA Reduction filters new [Re: grzybu]
      #6213143 - 11/24/13 12:12 PM

I own the C102GT, which is really an F/10.31 97mm scope. The chromatic aberration isn't that bad, really, with a F/R of 2.7, still, the Lumicon MV filter (for $72) and especially the Thousand Oaks MV-25 for $59 are candidates. Anyone have experience with either of these and an F/R 2.7-ish scope?

Most of the talk in this thread focuses on scopes with much lower F/R, and I understand, owned an Orion 100mm F/6 back in the day, but that day's come and gone for me. This scope, tho, doesn't possess CA at such a wretched level. I'm inclined to not worry about it, but these two, the Lumicon MV and the Thousand Oaks MV-25, might be worth it for Jupiter and Mars, and maybe Saturn. I've already looked at Venus and the Moon. CA on the moon, as mentioned earlier, just isn't as big a deal, at least not in this scope. The moon is SO bright and white, just don't find it bothersome. Yes, it's very apparent on Venus, but Venus is either a crescent or it isn't. The CA is quite apparent, but I can easily see the phase, and that's about all there is to care about, visually, so I have no problem with the CA on Venus. Interesting to see how much of an achro it is on Venus, but not bothersome at all.

But Jupiter, Mars and Saturn, for the 1st half of 2014 and beyond, are very detailed, and CA could be an issue with them. Would either of these be a bonus and not lose too much light for this little achro? Thoughts, recommendations? Thanks ahead of time.


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spongebob@55
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Re: CA Reduction filters new [Re: DeSoto Kid]
      #6213239 - 11/24/13 12:50 PM

Quote:

Quote:

Quote:

sBob you'll get better results with your telescope if you stack a Fringe filter with a Moon and Skyglow.




Ok, I have both of those. I try it! Perhaps it won't be so yellow? So do you think that this is the combination of filters for just the moon, or also for planets?

Thanks
Bob




Bob,
Have you tried the Fringe Filter with the Moon and Skyglow yet? I'm anxious to learn of the result.
Wayne R.




Hi Wayne R. et al,
No, Haven't been able to try it. I had a total L hip replacement on the 11th, so I'm recuperating. But I'm so good, (unbelievably so) that if the skies had be clear and if I could've gotten someone to bring out my EQ-G mount, I'd would have been out there trying this out. I'll post when I do. Wish me clear and warmer and less wind skies!
Sbob


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t.r.
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Re: CA Reduction filters new [Re: spongebob@55]
      #6213342 - 11/24/13 01:47 PM

Quote:

Most of the talk in this thread focuses on scopes with much lower F/R, and I understand, owned an Orion 100mm F/6 back in the day, but that day's come and gone for me. This scope, tho, doesn't possess CA at such a wretched level.




It is funny how we tolerate CA to very disparate levels. I have the 102GT and a 80mm F/5...for me, CA is CA, at about 80-100x I need a filter in either to go to higher mag. The short tubes are worth their weight or lack thereof IMHO.


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azure1961p
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Re: CA Reduction filters new [Re: spongebob@55]
      #6213348 - 11/24/13 01:50 PM

You'll like it when you do it. Those two filters stacked offer a nice cool tone to the moon nixing virtually all the yellow. Its a great combo.

Pete


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De Lorme
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Reged: 12/30/08

Re: CA Reduction filters new [Re: azure1961p]
      #6213374 - 11/24/13 02:08 PM

Do the 2 together dim the Moon any? De Lorme

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sg80
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Re: CA Reduction filters new [Re: De Lorme]
      #6213582 - 11/24/13 04:36 PM

I have yet to look at Jupiter this season.with my first scope 80mm 11.4 with my lumicon mv filter and 82 blue combo.but it,s nice on Luna the few times.I have used the two together.my scope does not have much ca but.I notice it on Jupiter.I have a fringe killer that removes more ca but the tint is a bit yellow.

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russell23
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Re: CA Reduction filters new [Re: sg80]
      #6238780 - 12/07/13 10:52 AM

Agena has the Baader 495 Longpass back in stock for those that have been looking for one.

Dave


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Vondragonnoggin
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Re: CA Reduction filters new [Re: russell23]
      #6238980 - 12/07/13 12:35 PM

Interesting thread. Sold my FK. Kept my M&SG and even use that on my MCT. Kept my Semi-Apo. The Semi-Apo was my favorite on my AR127. Completely corrects the color shift and I did not experience the same ghosting, or whatever was causing an odd halo-like artifact, I did by stacking filters (there was a noticeable halo like effect with FK and M&SG filters stacked).

The Semi-Apo dimmed the image compared to just the FK, so I corrected it by selling the AR127 and getting an Istar 150.

Will know how the semi apo performs when the new scope gets here and I can try it.


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Vondragonnoggin
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Re: CA Reduction filters new [Re: Vondragonnoggin]
      #6239019 - 12/07/13 12:49 PM

I have to mention thanks too. This type of research is really beneficial for those that want an achro in the shorter fl's. Not everyone can swing for a big Apo, but they still want a big refractor. To my eyes, filters made a marked improvement that was enough to justify my cost of the filter and then some.

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*skyguy*
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Re: CA Reduction filters new [Re: Vondragonnoggin]
      #6239044 - 12/07/13 01:01 PM

Quote:

The Semi-Apo dimmed the image compared to just the FK, so I corrected it by selling the AR127 and getting an Istar 150.




WOW! That's an expensive solution to a minor dimming problem ... however, I wholeheartedly approve!


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vct123
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Re: CA Reduction filters new [Re: *skyguy*]
      #6239826 - 12/07/13 08:43 PM

I own a Celestron 100ed and use it for Jupiter and lunar viewing and its a great scope. I just purchased a used Vixen 140na on A-mart and ordered the 495 long pass filter because of this thread. If a $60 filter can give the vx140 better views and other achro's better views, that's all that matters. Its great that we have access to shared threads like these to help each other, and if some don't think it works for them, that's ok, what you see is what you get.

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Vondragonnoggin
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Re: CA Reduction filters new [Re: *skyguy*]
      #6239867 - 12/07/13 09:16 PM

Quote:

Quote:

The Semi-Apo dimmed the image compared to just the FK, so I corrected it by selling the AR127 and getting an Istar 150.




WOW! That's an expensive solution to a minor dimming problem ... however, I wholeheartedly approve!




I think if I still find it dims too much, an Istar 8" F/6....



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De Lorme
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Re: CA Reduction filters new [Re: Vondragonnoggin]
      #6240002 - 12/07/13 10:54 PM

Now that's a great idea! De Lorme

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azure1961p
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Re: CA Reduction filters new [Re: De Lorme]
      #6240027 - 12/07/13 11:14 PM

I agree the M&SG filter is good on all scopes not just a refractor. Nice gentle multi color/contrast enhancer. Very modest cool color shift - to the benefit of jupiters warm hues.

Pete


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Jon_Doh
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Re: CA Reduction filters new [Re: azure1961p]
      #6240442 - 12/08/13 09:33 AM

Von, how were you stacking the filters? Usually if you put the Fringe in the diagonal and the M&S in the eyepiece you will not get ghosting or dimming.

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Vondragonnoggin
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Re: CA Reduction filters new [Re: Jon_Doh]
      #6240562 - 12/08/13 11:11 AM

Quote:

Von, how were you stacking the filters? Usually if you put the Fringe in the diagonal and the M&S in the eyepiece you will not get ghosting or dimming.




Correct, but I change eyepieces frequently, so I had them stacked directly. The effect was good where it corrected the yellowing back to white, but produced the halo, so I bought the Semi-Apo which is essentially the same as the two stacked. One filter in the diagonal and change eyepieces all night.

Like I said though, I sold the FK. Wasn't needed after Semi-Apo because I didn't find it actually dimmed very much but the color correction was excellent.

Just used the M&SG on my MCT on Jupiter last night. It does make Jupiter views seem to pop better in the MCT in regards to banding and details.

Any time you use the M&SG you will get some dimming. It's neglible to me. Well worth the appearance of contrast boosting.

Edited by Vondragonnoggin (12/08/13 11:13 AM)


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Niklo
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Reged: 03/29/13

Loc: Bavaria
Re: CA Reduction filters new [Re: Vondragonnoggin]
      #6244278 - 12/10/13 08:58 AM

I found an interesting comparison in a German forum.
http://www.astrotreff.de/topic.asp?TOPIC_ID=159565
What do you think about the pictures? The Jupiter photos are
1. stopped down to 110/1200 mm no filter, 150/1200 mm no filter, fringe killer, skyglow, Fringekiller+Skyglow, SemiAPO, Chromacorr, APO 125/1000.
The moon pictures are stopped 110mm/1200mm, 150/1200 mm, fringekiller, skyglow, Fringekiller + Skyglow, SemiAPO.

The Jupiter photos with FringeKiller+Skyglow and SemiAPO are not sharp and show less than without filter.
For the moon the SemiAPO photo is sharp and the combination Skyglow+Fringekiller is not sharp. So probably it does not depend on the filter but finding the focus.

How is your experience?
Clear skies,
Roland


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Vondragonnoggin
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Re: CA Reduction filters new [Re: Niklo]
      #6244296 - 12/10/13 09:10 AM

I don't know about any of those pictures, but having owned all three, they are all sharp in focus.

I stand by my experience that at high powers, the semi-Apo is the filter for me for killing CA and not yellowing the view. Whichever filters work for the individual is great. The main point is that you see an improvement in the view by the filters use.

I'll continue to use my M&SG filter on any scope as long as the view doesn't dim too much.


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Niklo
sage


Reged: 03/29/13

Loc: Bavaria
Re: CA Reduction filters new [Re: Vondragonnoggin]
      #6244321 - 12/10/13 09:30 AM

What achromat do you own and does it really improve the details with the Semiapo filter?
Clear skies,
Roland


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t.r.
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Re: CA Reduction filters new [Re: *skyguy*]
      #6244343 - 12/10/13 09:47 AM

Quote:

Quote:

The Semi-Apo dimmed the image compared to just the FK, so I corrected it by selling the AR127 and getting an Istar 150.




WOW! That's an expensive solution to a minor dimming problem ... however, I wholeheartedly approve!


Classic...only in the refractor forum!!!




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Vondragonnoggin
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Re: CA Reduction filters new [Re: Niklo]
      #6244350 - 12/10/13 09:51 AM

AR127 was the scope I owned. F/6.5 and yes, for me, it really improved the view as far as details go. The filtering of unfocused light made the focus appear much sharper at high powers. Sold the scope though. Waiting on delivery of my new scope where I will most likely get a lot of use out of it again. New scope is F/5 Istar.

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Niklo
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Loc: Bavaria
Re: CA Reduction filters new [Re: Vondragonnoggin]
      #6244402 - 12/10/13 10:14 AM

Thank you very much. So the filters improved the view in the 5" f/6,5.
And the new scope will be an 4" or 5" Istar f/5?
Clear skies,
Roland


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Vondragonnoggin
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Re: CA Reduction filters new [Re: Niklo]
      #6244413 - 12/10/13 10:17 AM

Quote:

Thank you very much. So the filters improved the view in the 5" f/6,5.
And the new scope will be an 4" or 5" Istar f/5?
Clear skies,
Roland




6" F/5 with R35 lens. A short stubby yard cannon.


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ohioalfa64
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Reged: 08/16/12

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Re: CA Reduction filters new [Re: Vondragonnoggin]
      #6252540 - 12/14/13 12:05 PM

These filters add to viewing on a MCT? With their added focal lengths how much do can they help? What am I forgetting?

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Vondragonnoggin
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Re: CA Reduction filters new [Re: ohioalfa64]
      #6252583 - 12/14/13 12:34 PM

Well, you'd have to try one in your MCT on Jupiter and see for yourself. Just the Moon & Skyglow filter is all I use in my MCT. As far as focal length difference, I'm not seeing image scale increase with same fl eyepieces.

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jcricket
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Re: CA Reduction filters new [Re: Vondragonnoggin]
      #6252802 - 12/14/13 02:37 PM

Quote:

Quote:

Thank you very much. So the filters improved the view in the 5" f/6,5.
And the new scope will be an 4" or 5" Istar f/5?
Clear skies,
Roland




6" F/5 with R35 lens. A short stubby yard cannon.




Do you actually have on of these scopes? I just ordered mine and it is due within the next two weeks.

Also, I just tried to read this whole thread and my brain is pickled now.
What would you folks say is the ranking matrix for these filters discussed, say from best to worst?
The 495 long pass to the #8 maybe?
Any dare make a stab at listing these in order of usefulness(cost aside).
Thanks,
MArk


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De Lorme
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Re: CA Reduction filters new [Re: jcricket]
      #6253004 - 12/14/13 04:41 PM

For me the 495 Longpass. I had a Moon & Sky glow and to me
it dimmed the image. As you already know the Longpass makes the stars pinpoint. On the moon the craters and mountain
ranges are more distinctive. Focusing for me is just so much easier now. Plus it cost half of what the others cost.
De Lorme


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russell23
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Re: CA Reduction filters new [Re: jcricket]
      #6253123 - 12/14/13 06:10 PM

Quote:

Quote:

Quote:

Thank you very much. So the filters improved the view in the 5" f/6,5.
And the new scope will be an 4" or 5" Istar f/5?
Clear skies,
Roland




6" F/5 with R35 lens. A short stubby yard cannon.




Do you actually have on of these scopes? I just ordered mine and it is due within the next two weeks.

Also, I just tried to read this whole thread and my brain is pickled now.
What would you folks say is the ranking matrix for these filters discussed, say from best to worst?
The 495 long pass to the #8 maybe?
Any dare make a stab at listing these in order of usefulness(cost aside).
Thanks,
MArk




It depends upon your goal. If complete elimination of CA is your goal then the Baader 495 longpass is the best choice. If you don't like the color shift of the 495 longpass then the #8 light yellow is the best choice as it is identical to the Fringe Killer in performance. The Baader Semi-APO will noticeably dim the image.

For me the Baader 495 Longpass is the filter I prefer.

Dave


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mikey cee
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Re: CA Reduction filters new [Re: De Lorme]
      #6253127 - 12/14/13 06:11 PM

I can achieve that much wuith a cheap #8. You don't have to spend a chunk of change to turn everything yellow. Mike

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jcricket
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Loc: Denver Area
Re: CA Reduction filters new [Re: mikey cee]
      #6253201 - 12/14/13 06:51 PM

I happen to get a lumicon MV with a box of stuff. I have never needed it as I have always had newts. I am getting the 6" f/5 so I am starting to look into this.

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Vondragonnoggin
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Re: CA Reduction filters new [Re: jcricket]
      #6253391 - 12/14/13 08:39 PM

Quote:

Quote:

Quote:

Thank you very much. So the filters improved the view in the 5" f/6,5.
And the new scope will be an 4" or 5" Istar f/5?
Clear skies,
Roland




6" F/5 with R35 lens. A short stubby yard cannon.




Do you actually have on of these scopes? I just ordered mine and it is due within the next two weeks.

Also, I just tried to read this whole thread and my brain is pickled now.
What would you folks say is the ranking matrix for these filters discussed, say from best to worst?
The 495 long pass to the #8 maybe?
Any dare make a stab at listing these in order of usefulness(cost aside).
Thanks,
MArk




No, still waiting on the scope like you. I acquired my filters for CA reduction and my experiments with them using a 5" ES AR127.

The AR127 was sold. That's why I'm getting the Istar. I sold my fringe killer with the scope. Kept M&SG and Semi-Apo. I knew I would get a bigger achro soon.

When people talk dimming with the Semi-Apo I think it must be individual preference. I did not find the Semi-Apo dims very much at all. It is actually a pleasing effect on the view at both low and high powers for me.

I think when achros start getting in the 127mm and up range, a little dimming is not going to be as detrimental as with a 60mm - 100mm scope.

I greatly preferred the return of color balance over a yellowed view.

Bottom line is this stuff is highly individual on affect, preference, etc.

Many prefer to just use their scopes with no reduction filters.

It's trial and error because you don't know if you will like it or think its worth filter costs until you try it.

All filters mentioned will readily sell on the used market, so if you feel like it, take the chance (if you have the funds to try a few filters). Investments like the Longpass, which is a fairly inexpensive filter, aren't too much of a gamble to me, while the Semi-Apo in 2" format is a chunk of change.

I took the plunge knowing how fast they sell off used.

Edited by Vondragonnoggin (12/14/13 08:45 PM)


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buddyjesus
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Re: CA Reduction filters new [Re: Vondragonnoggin]
      #6257305 - 12/16/13 11:21 PM

the reason I use the lighter yellow over a darker one or CA filter is both financial and that my eye/brain doesn't let it look so yellow. The yellowing shouldn't be a bother for most I figure since TV sells plenty of eyepieces like that! haha. couldn't resist!

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spongebob@55
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Re: CA Reduction filters new [Re: buddyjesus]
      #6258201 - 12/17/13 01:43 PM

I have a #8 too. I have yet been able to compare the #8 with the 495. Its been so long since I've had an observing session, that I've been unable. I do recall the 495 really made the moon yellow, displeasing to me. Yet on the stars, wow...beautiful. Of course we're having our second early snow here in 3 days. And on top of my 'new hip', this is driving me nuts.
Bob


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Vondragonnoggin
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Re: CA Reduction filters new [Re: spongebob@55]
      #6258230 - 12/17/13 01:59 PM

Quote:

And on top of my 'new hip', this is driving me nuts.
Bob




Probably the square pants will cause hip problems, but what can you do?



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Usquebae
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Re: CA Reduction filters new [Re: Vondragonnoggin]
      #6259789 - 12/18/13 10:25 AM



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