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Equipment Discussions >> Eyepieces

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Sarkikos
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Reged: 12/18/07

Loc: Scotophobe Maryland, USA
Re: Filters for Jupiter new [Re: and75]
      #5555958 - 12/05/12 04:37 PM

Quote:

The main impression on the M&SG is that it's good, noticed some improvement... but not a big deal. The blue color filter did just the same performance (for free) I can't screw the blue filter into the eyepiece, perhaps I will invest into a real astro-filter, a Baader light blue.




Yep, no filter will perform miracles for planets or even show you anything that you couldn't see without it. But a good filter will make it easier for you to see what's there.

Quote:

I have never heard about that white paper trick, it sounds good, I'll try it asap.




It's nothing new. Planet observers have been keeping white light around themselves for a long time. But it does seem that it's a trick that's been forgotten or ignored. Otherwise you wouldn't hear all the complaints in these threads about how bright Jupiter is!

My preference, though, is to only expose my eyes to the white light - I mean a reflection of the light - every ten minutes or so, instead of having a constant light on near where I observe. It's too easy for a bright light that's constantly on to introduce glare - real glare - into the optics or your eyes while you're observing.


Mike


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Cames
sage


Reged: 08/04/08

Re: Filters for Jupiter new [Re: Dick Jacobson]
      #5555981 - 12/05/12 04:50 PM

Wow! Thank you all for the great hints. And, now that you mention it, I alternate eyes when one eye fatigues after prolonged gazing and I've noticed that Jupiter appears very washed out in the new eye at first but then gradually develops more contrast and detail. One reason why I was pursuing the filter route is that passing haze or thin clouds seemed to bring out detail that went unnoticed under more transparent conditions.

We're going to be socked in with clouds for the next few days. I'm going to implement your suggestions on the next clear night.


Again, many thanks

------
Cames


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StarStuff1
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Reged: 04/01/07

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Re: Filters for Jupiter new [Re: Cames]
      #5556002 - 12/05/12 05:00 PM

For grins try an OIII filter. You will get a psychedalic planet but there will be details that were not there before.

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GeneT
Ely Kid
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Reged: 11/07/08

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Re: Filters for Jupiter new [Re: Cames]
      #5556036 - 12/05/12 05:22 PM

Most who post on this issue will disagree with me. However, after years of using a variety of planetary filters, I finally decided I could see as much detail without any. I made a club member very happy when I gave my planetary filters to him--for free.

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Scanning4Comets
Markus
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Reged: 12/26/04

Loc: Ontario, Canada
Re: Filters for Jupiter new [Re: GeneT]
      #5556085 - 12/05/12 05:58 PM

Quote:

I hate to belabor the point, but all this talk about Jupiter being too bright, too much glare, need to dim the image, are off the mark. Unless you're observing with a really big scope - maybe a 26" or bigger? - the problem isn't that Jupiter is too bright. The problem is that your eyes aren't properly prepared to observe Jupiter.

Mike




Well, the problem is not that Jupiter, (or Mars for that matter), is 'too bright", the problem many planetary observers, including myself, come across is NEEDING THE RIGHT CONTRAST.

Irradiation on bright areas and dark areas bleed over into each other, especially on Jupiter, and even more so for Mars. Dimming these planets to desirable levels makes observation of bright / dark areas a lot easier. This also makes it a lot easier and better to observe small detail when the atmosphere and telescope allows it. Color filters also help bring out detail as they reject / cancel certain wavelengths of light, making colors stand out more.

Cheers,


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Sarkikos
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Reged: 12/18/07

Loc: Scotophobe Maryland, USA
Re: Filters for Jupiter new [Re: Scanning4Comets]
      #5556192 - 12/05/12 06:53 PM

Yes, I agree that lack of contrast is a problem. There are a number ways to enhance perceived contrast for planets. Filters can help. So can an apodizing mask for Newts. Binoviewers are of benefit. Very close collimation is very important, and is often overlooked by observers. Thermal stabilization of the optics is necessary for a sharp image. We should also mention decent eyepieces.

But all these methods deal with the optical equipment. What about the observer's eyes?

If the observer says Jupiter is "too bright," that doesn't indicate the contrast in the image is too low but that the image appears too bright to their eyes. I'll take them at their word. IME, the best solution is not to dim the image but to improve the adaptation of the eyes.

Mike


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Scanning4Comets
Markus
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Reged: 12/26/04

Loc: Ontario, Canada
Re: Filters for Jupiter new [Re: Sarkikos]
      #5556289 - 12/05/12 07:48 PM

The title of this thread is "filters". The rest is obvious, (collimation, etc, etc, etc). Contrast is the key to all observing being it planetary or deep sky.

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Sarkikos
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Reged: 12/18/07

Loc: Scotophobe Maryland, USA
Re: Filters for Jupiter new [Re: Scanning4Comets]
      #5556324 - 12/05/12 08:03 PM

The OP did mention that "Jupiter appears very bright." That raises a red flag for me. I am compelled to address it. The assumption was made that the cure for Jupiter's brightness is to use filters, but that isn't necessarily the only or the best solution.

Mike


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JIMZ7
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Reged: 10/22/05

Loc: S.E.Michigan near DTW
Re: Filters for Jupiter new [Re: Sarkikos]
      #5556958 - 12/06/12 06:54 AM

My past experiences with different scopes from 80mm to 203mm-the filters I liked the most were #80A-blue**#11-green/yellow**& #ND of different percentages. On a Discovery 12.5" f/5 Dob. with no filters Jupiter's belts were nicely viewed at 511x.

Jim


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Jaimo!
Pooh-Bah
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Reged: 10/11/07

Loc: Exit 135 / 40° North
Re: Filters for Jupiter new [Re: Jaimo!]
      #5557125 - 12/06/12 09:24 AM

Quote:

Mike,
If you look into a flash light to stop down your pupil diameter, couldn't you accomplish the same thing with a smaller scope? I find my 12" dob a little much for Jupiter, but great for deep sky, and typically get my best views at 6-8"...

Jaimo!




Maybe I should be pushing the magnification... I am typically hovering around 200-250x, with the increased magnification I should also have a reduction in light throughput. I'm still a Dob novice...

Thanks,
Jaimo!


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Sarkikos
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Reged: 12/18/07

Loc: Scotophobe Maryland, USA
Re: Filters for Jupiter new [Re: Jaimo!]
      #5557159 - 12/06/12 09:47 AM

Jaimo!

In the experience of many observers - myself included - Jupiter doesn't take higher magnification as well as Mars or Saturn. When viewing Jupiter with my 10" f/4.8 Dob, I usually keep it at 250x or below. That's 25x per inch and 1mm exit pupil. If the eyes are kept near photopic - especially if other methods of enhancing contrast are used - very fine surface detail can be seen at this image scale. Don't let anyone tell you it can't be done, because I know for a fact that it can. (I think some folks just like to push the power.) For your 12" f/4.9, a comparable power would be 300x. Try for that if the seeing will allow.

But whatever you do, don't look directly into the flashlight! I have never said to do that. Just look at a reflection of the white light on a white piece of paper.

Mike


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dpwoos
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Reged: 10/18/06

Loc: United States
Re: Filters for Jupiter new [Re: Sarkikos]
      #5557967 - 12/06/12 05:44 PM

Quote:

In the experience of many observers - myself included - Jupiter doesn't take higher magnification as well as Mars or Saturn.




I have no idea what it means for something to not "take" higher magnification. Sounds like an equipment problem to me. Care to elaborate?


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Peter Natscher
professor emeritus


Reged: 03/28/06

Loc: Central Coast California
Re: Filters for Jupiter [Re: Starman1]
      #5558358 - 12/06/12 09:57 PM

Ditto on that technique! Jupiter through my 24" dob is too bright with one eyepiece, no filter and under 300X. Neutral density filters and especially binoviewing cut down enough light and glare to see the surface details. I usually stack 2" M&SG and 50% ND filters together front-side on the Mark V bino and use 350X-450X on good seeing nights to get the view I like.

Quote:

Quote:

Mike,
If you look into a flash light to stop down your pupil diameter, couldn't you accomplish the same thing with a smaller scope? I find my 12" dob a little much for Jupiter, but great for deep sky, and typically get my best views at 6-8"...

Jaimo!



But the smaller scope will lose resolution.
If dimming the image in a larger scope enables you to see more details (and sometimes it does), try a light #50 neutral density filter or a #82A light Blue. The ND won't change the color.

However, I've found coloration in bands and details to be greater in greater aperture. My best view of Jupiter in color was in a 28" scope with no filter.

And remember, double the power and the image is 1/4 as bright per unit area. My best views of Jupiter have all been over 300X.




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DeSoto Kid
super member


Reged: 08/24/07

Loc: DeSoto, Texas
Re: Filters for Jupiter new [Re: Peter Natscher]
      #5558714 - 12/07/12 06:40 AM

What about using a Kendrick focusing aid cover available for SCT,s etc.? The one for the C9.25 has 3 - 3" holes around the periphery of the scope entrance. Being close to the outer edge should not reduce resolution so much and being positioned on the outer half of the scope might reduce spherical abberation if present. The single equivilet in area of these 3 spheres would be a 5" sphere ... and all this with NO central obstruction. This would reduce quite a bit of the light coming in.

Bob (REC) mentioned that brightness of Jupiter was not so severe when he first beging observing. It my be a good idea to eliminate this phenomenon before it happens ...???

Wayne


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Sarkikos
Postmaster
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Reged: 12/18/07

Loc: Scotophobe Maryland, USA
Re: Filters for Jupiter new [Re: dpwoos]
      #5558739 - 12/07/12 07:11 AM

dpwoos,

Quote:

Quote:

In the experience of many observers - myself included - Jupiter doesn't take higher magnification as well as Mars or Saturn.




I have no idea what it means for something to not "take" higher magnification. Sounds like an equipment problem to me. Care to elaborate?




No, it is not an equipment problem.

Of course, any object can "take" any magnification you care to throw at it, in the sense that you can setup the equipment to have that magnification. But will the image show you any more surface detail than at a more moderate magnification? Some objects will, some won't. Jupiter is one of those that don't "take" high magnification well, as compared to Saturn or Mars or double stars, for instance. This is nothing new.

A largely ignored factor in the equation of how much magnification is needed to see a high level of fine detail is how well the observer's eyes have been prepared for observing planets. IME & IMO, many observers don't have a clue how to do this, or even that it will make a difference. If the eyes are properly prepared, the observer shouldn't have to push the magnification - with some exceptions, such as close double stars, subtle detail in Saturn's rings and Mars at a small apparent diameter. (I've pushed a 6 arcsec Mars up to 600x in my 10" Dob with good results.)

I'm not usually a big fan of huge image scale for its own sake, particulary since my best planet scopes don't track. What I'm after is finer detail. I can see that without crazy-high power when observing Jupiter.

Mike


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Sarkikos
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Reged: 12/18/07

Loc: Scotophobe Maryland, USA
Re: Filters for Jupiter new [Re: Peter Natscher]
      #5558768 - 12/07/12 07:48 AM

Peter,

Quote:

Ditto on that technique! Jupiter through my 24" dob is too bright with one eyepiece, no filter and under 300X. Neutral density filters and especially binoviewing cut down enough light and glare to see the surface details. I usually stack 2" M&SG and 50% ND filters together front-side on the Mark V bino and use 350X-450X on good seeing nights to get the view I like.

Quote:

Quote:

Mike,
If you look into a flash light to stop down your pupil diameter, couldn't you accomplish the same thing with a smaller scope? I find my 12" dob a little much for Jupiter, but great for deep sky, and typically get my best views at 6-8"...

Jaimo!



But the smaller scope will lose resolution.
If dimming the image in a larger scope enables you to see more details (and sometimes it does), try a light #50 neutral density filter or a #82A light Blue. The ND won't change the color.

However, I've found coloration in bands and details to be greater in greater aperture. My best view of Jupiter in color was in a 28" scope with no filter.

And remember, double the power and the image is 1/4 as bright per unit area. My best views of Jupiter have all been over 300X.







Please folks, stop copying Jaimo!'s incorrect description of the "Bright White Light" technique. It will do no one any good to look directly into a bright flashlight! Instead, look at the reflection of that light onto a white piece of paper!

Peter: I agree on binoviewing and the use of M&SG filters. Yep, at around 24" or so you might be hitting the threshold at which you actually do need to think about dimming Jupiter's image a bit.


Mike


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Sarkikos
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Reged: 12/18/07

Loc: Scotophobe Maryland, USA
Re: Filters for Jupiter new [Re: DeSoto Kid]
      #5558783 - 12/07/12 08:03 AM

Wayne,

Quote:

What about using a Kendrick focusing aid cover available for SCT,s etc.? The one for the C9.25 has 3 - 3" holes around the periphery of the scope entrance. Being close to the outer edge should not reduce resolution so much and being positioned on the outer half of the scope might reduce spherical abberation if present. The single equivilet in area of these 3 spheres would be a 5" sphere ... and all this with NO central obstruction. This would reduce quite a bit of the light coming in.

Bob (REC) mentioned that brightness of Jupiter was not so severe when he first beging observing. It my be a good idea to eliminate this phenomenon before it happens ...???




The brightness of Jupiter should not be a problem in a 9.25" aperture. If Jupiter appears too bright, your eyes are not prepared optimally for observing Jupiter. It is not a good idea to reduce the aperture in order to reduce the brightness of a planet. You will be decreasing the resolution while trying to solve a problem that doesn't really exist.

Placing a ring around the aperture might cover up optical errors. But reducing aperture because a planet appears "too bright" is not a good solution to the problem of "brightness" - which actually is not a problem at all in moderate-sized scopes.

Mike


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dpwoos
Pooh-Bah
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Reged: 10/18/06

Loc: United States
Re: Filters for Jupiter new [Re: Sarkikos]
      #5558790 - 12/07/12 08:09 AM

Quote:

dpwoos,

Quote:

Quote:

In the experience of many observers - myself included - Jupiter doesn't take higher magnification as well as Mars or Saturn.




I have no idea what it means for something to not "take" higher magnification. Sounds like an equipment problem to me. Care to elaborate?




No, it is not an equipment problem.

Of course, any object can "take" any magnification you care to throw at it, in the sense that you can setup the equipment to have that magnification. But will the image show you any more surface detail than at a more moderate magnification? Some objects will, some won't. Jupiter is one of those that don't "take" high magnification well, as compared to Saturn or Mars or double stars, for instance. This is nothing new.




You again state your claim that Jupiter (unlike Saturn, Mars, etc.) doesn't "take" high magnification, but still don't explain why you think that. I often view Jupiter (and other high mag targets) at 250x in my 10" because that seems to be what the seeing on good nights most often allows. However, I have also observed Jupiter in the same scope at 400x, and I am quite certain that I was able to see fine detail that was not visible at the lower mag, and as one would expect. Honestly, I have no idea how one can possibly maintain that there is some minimum exit pupil size (I take it around 1mm?) that shows all there is to see on this target specifically, especially given the seemingly infinite amount of detail visible?


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Sarkikos
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Reged: 12/18/07

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Re: Filters for Jupiter new [Re: dpwoos]
      #5558831 - 12/07/12 08:34 AM

dpwoos,

Quote:

You again state your claim that Jupiter (unlike Saturn, Mars, etc.) doesn't "take" high magnification, but still don't explain why you think that.




It's not a claim. It's an honest report of personal experience. An explanation of why it happens is another matter. Low contrast detail on Jupiter as opposed to high contrast detail on Saturn's rings? Larger image scale of Jupiter as opposed to the usually smaller image scale of Mars? I think those are good explanations.

Quote:

I often view Jupiter (and other high mag targets) at 250x in my 10" because that seems to be what the seeing on good nights most often allows. However, I have also observed Jupiter in the same scope at 400x, and I am quite certain that I was able to see fine detail that was not visible at the lower mag, and as one would expect. Honestly, I have no idea how one can possibly maintain that there is some minimum exit pupil size (I take it around 1mm?) that shows all there is to see on this target specifically, especially given the seemingly infinite amount of detail visible?




Well, good for you. Or maybe not so good, if you actually need higher magnification to see what I'm seeing at more moderate power. My scopes don't track, so I try to avoid higher power if I can. I don't need a substantially larger image scale for Jupiter in order to see fine surface detail. I know through experience how to avoid that. To each their own.

Mike


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coutleef
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Reged: 02/21/08

Loc: Saint-Donat, Quebec, Canada
Re: Filters for Jupiter new [Re: Sarkikos]
      #5558926 - 12/07/12 09:51 AM

i agree with Mike here

Jupiter is the planet for which higher magnification is generally not as useful as for other planets. the most useful mag is around 160-180. while i use much higher mags with Saturn and mars, when i use high mags pn Jupiter, i do not see more detail but i loose some.


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