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PVS-7 Night Vision goggle filter candidates

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#1 The Ardent

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Posted 26 September 2015 - 11:36 PM

Here is a list of filters that I want to experiment with this PVS-7 night vision. 

 

I tested two filters already with my impression: 

Astronomik H-alpha 656 13nm: very good for nebula, PVS-7 stock lens

Televue Bandmate Nebustar: stars dimmed, no nebula seen (no surprise there) 

 

I have two more on order: 

Baader 610 Longpass (equivalent to Lumicon #29 Dark Red???) 

Lumicon Night Sky H-a (equivalent to Baader H-a 35nm???) 

 

I don't need any more filters, but curious as to the effects of these. I will be using PVS-7 with camera lens, 3 and 4" refractor, and 18" dob. 

 

Filter name.                          Wavelength 

 

Astronomik IR Pass              807 to 1100nm
Astronomik IR Pass              742 to 1100nm
Baader IR Pass                     685
Baader  Sulfur II                    672 8nm
Baader  H-alpha                    656 35nm
Astronomik H-alpha               656 13nm
Baader  H-alpha                    656 7nm
Astronomik IR Pass               642 to 842
Lumicon Night Sky H-a         640
Baader Red Longpass          610
Lumicon #29 Dark Red          600
Lumicon #25 Red                  580
Baader Orange Longpass     570
Lumicon #23 Light Red         550
Lumicon #21 Orange             530
Lumicon #15 Yellow-Or         510
Lumicon #12 Yellow              500
Baader Yellow Longpass      495

 

sorry for any formatting errors, IPad isn't the best for that



#2 Vondragonnoggin

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Posted 27 September 2015 - 12:09 AM

In order to help with filter selection, it is important to understand the following things:

 

What is the spectrum curve of the image intensifier?

What is the goal of filtering? Is it to block unwanted spectra or increase signal to noise on objects at certain emission lines or combination of both?

What is the spectrum curve of the unwanted source when blocking?

What is the full spectrum curves of the filter? Is it in a useful range relating to spectrum of device output and useful to emission of astronomical object viewed?

 

The most common Gen 3 devices we see in the forum here (BIPH, Collins I3, NVD Micro, PVS-7 or similar device, use a GaAs photocathode with P43 (green) phosphor.

 

The tube similar in design to this - http://www.photonics...8/Figure4_6.jpg

 

The range of response of GaAs photocathodes can be seen here - http://www.ceoptics....ages/chart1.gif

 

The stuff we want to block includes the contributors to skyglow - http://www.prairieas...glow800x600.jpg

 

Light pollution being one of the major spectra in its various wavelengths - http://micro.magnet....rcesfigure3.jpg

 

Also the moon is an object contributing to unwanted light sources and spectrum emission looks like this - https://chakraborti....04/824_1-f1.jpg

 

So, the final thing we definitely should look at is composition of gases in nebulae, star emission for various star types, galaxy emission and visible spectra. These can vary greatly.

 

If you look at the spectrum of various vision types with the human eye, we see that night vision (dark adapted scotopic) is generally how visual filters are made to enhance the compositional gases in nebula in the visual range - http://www.mdpi.com/...3961f3-1024.png

 

Most visual filters in narrowband enhance emission lines in OIII, H-Beta, while blocking other sources up to some emissions in near IR or H-Alpha and up because we do not see red with scotopic vision

 

The trick to get filters that work for Gen 3 GaAs tube devices is to tailor the filter to best response of photocathode, best blocking of unwanted spectra, and best emission of gases or spectra of objects.

 

End of first post. I can contribute to information on thefollowing filters I use with NV astronomy:

3nm Ha

7nm Ha

610nm Longpass

Lumicon Night Sky H-Alpha - this is a 640nm Longpass actually

35nm Ha

685nm IR pass

 

I have tried some visual filters

Thousand Oaks LP2

Lumicon UHC

Lumicon OIII

Baader Moon & Skyglow Neodymium

Lumicon ND13

 

All visual filters were ineffective on Gen 3 GaAs devices with exception of the Baader M&SG Neodymium which cut LP a little to darken view. The other filters listed at top that I use with NV Astronomy are all effective to varying degrees and I can list objects and uses for each in next post.

 


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#3 cnoct

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Posted 27 September 2015 - 12:21 AM

 

 

Filter name.                          Wavelength 

 

Astronomik IR Pass              807 to 1100nm
Astronomik IR Pass              742 to 1100nm
Baader IR Pass                     685  :waytogo: 
Baader  Sulfur II                    672 8nm :undecided: 
Baader  H-alpha                    656 35nm :undecided: 
Astronomik H-alpha               656 13nm :waytogo: 
Baader  H-alpha                    656 7nm :waytogo: 
Astronomik IR Pass               642 to 842
Lumicon Night Sky H-a         640
Baader Red Longpass          610
Lumicon #29 Dark Red          600
Lumicon #25 Red                  580
Baader Orange Longpass     570
Lumicon #23 Light Red         550
Lumicon #21 Orange             530

Lumicon #15 Yellow-Or         510
Lumicon #12 Yellow              500
Baader Yellow Longpass      495

 

 

 

On those listed, the above edits reflect my opinion.

 

 

Solid info VDN :waytogo:


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#4 The Ardent

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Posted 27 September 2015 - 12:32 AM

I should have known!  :lol:

 

I'm still curious to try the IR pass in my 18", on M42 to see the infrared stars (I saw many hidden stars in M42, once, with my friend's Collins I3 in the 18" , years ago) 

 

im very satisfied with the Astronomik H-a 13nm so far.


Edited by The Ardent, 27 September 2015 - 12:35 AM.


#5 Vondragonnoggin

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Posted 27 September 2015 - 12:38 AM

So, here is my experience with the filters I have and what they do best in my opinion:

 

Lumicon Night Sky H-Alpha - recommended here in this forum as a longpass filter with sharp cutoff below 640nm. I find this filter better used to enhance both globular and open clusters in contrast, edge on galaxies, viewing hydrogen clouds of Milky Way and greatly dims the light pollution spectra to allow for much greater contrast on objects viewed. This one I prefer on larger scopes due to darker nature with cutoff at 640nm and blocking spectrum below that. With a large scope, it can still provide enough illumination to keep from getting a noisy view due to photon starvation. Nebula still are viewable although not a lot of contrast afforded to nebula compared to narrowband. Still alows plenty of star types to show through. I have 2" version of this filter.

 

Baader 610nm Longpass - very similar to Lumicon 640nm Longpass Ha filter. It is less aggressive and allows brighter views and is my filter of choice on camera lenses. Greatly enhanced contrast on most objects with exclusion to nebula which still show through enough to be very recognizable if in the very bright range of nebula high in Ha content. Very smooth appearance in device and allows enough light in to keep noise level way down. I have both 1.25" and 2" versions. The 2" versions highly effective attached to front of camera lenses with filter threads from 52mm to 62mm with stepdown rings.

 

Baader 685nm Longpass - this cuts out all Ha and very effective at light pollution filtering. Only clusters and galaxies high in near IR content show through. More noise in this filter in background as it is a very dark red filter. This one I might use in longer focal lengths when hunting fainter galaxies only or the smaller globulars. I have 1.25" version only of this one.

 

Baader 35nm CCD Ha filter - This is a narrowband filter on the wider side of things. This one is great for hydrogen clouds in Milky Way while still letting in some emission from stars emitiing light in this range. Not as useful to me as the narrower notched Ha filters. I have the 1.25" version.

 

Baader 7nm Ha filter - Highly useful filter for nebula allowing both NII and Ha lines through. Very dark filter and introduces starvation of photocathode causing more background noise in the system but prividing high signal to noise on nebula rich in Ha and NII content. I have both 1.25" and 2" versions of this filter. Interesting on fast focal ratio camera lenses to quickly spot large bright nebula. Very effective cutting LP and even some aspects of moonlight. Shows scintillation on dark background sky.

 

Omega 3nm Ha filter - More contrast on Ha rich targets but cuts out NII lines. The background sky in the view is entirely black with scintillation heavier due to starvation of photocathode. Highly effective in strong LP and moonlight. I have 2" version of this one. Great on nifty fifty Canon camera lens at F/1.8 to find big objects even if faint. This one for North American, Pelican, Gamma Cygnus in one view with 50mm lens or even Barnards Loop.


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#6 Vondragonnoggin

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Posted 27 September 2015 - 12:46 AM

Cnoct - your emoticon next to the 35nm describes it good. Haha.



#7 Vondragonnoggin

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Posted 30 September 2015 - 06:39 AM

Stickied thread on filters and intensifiers - linked in best of EAA pinned thread

http://www.cloudynig...fier-eyepieces/

 

Maybe we could get this info tacked onto that thread?


Edited by Vondragonnoggin, 30 September 2015 - 06:42 AM.


#8 The Ardent

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Posted 06 October 2015 - 04:18 AM

Monday Oct 5 2015: first day of sunshine after days of rain. I visited Mr. Catapoman, a longtime visual observer. The night was 60% cloudy with poor seeing. I asked him: would you normally set up your scope tonight? "No" was the answer. I pulled out the PVS7+ 50mm SLR lens+ Lumicon night sky filter. "Neat" was his response. We scanned the Milky Way thru the thin clouds. Switched to the stock lens with 13nm H-a. "Now try this" I knew what was coming, and wasn't disappointed when I heard the "jaw drop" sounds from a veteran observer. 

 

Next trial with a Stellavue 4" f/7 on an alt-az mount. Multitudes of stars in every FOV, M13 and M22 resolved like with large aperture, but small from the low magnification. With the H-a M16, M17, NGC 281, Crescent NGC 288  all visible. The view was much dimmer with lots of scintillation. Neither of us had ever seen the Gamma Cygni nebulousity before. 

 

After returnng home home I spent a couple of hours with my 3" f/6.6 refractor. I tried the focal reducer in front of the diagonal and in front of the PVS7 but was unable to reach focus. This is the 2" FR with 2" diagonal. Perhaps the 1.25 versions of the same will allow more back-focus? 

 

Filter results: 

Only H-a gave impressive results on nubulae, but dim view with refractors

Baader 610 Longpass and Lumicon Night Sky and old Olympus red SLR filter gave similar results. The Lumicon perhaps a touch better. 

 

The H-a allows views of otherwise invisible nebulae. I was able to see Horsehead in 3" scope. Not well, but it was visible.  M42 was improved with the red filter, and absolutely stunning with the H-a. 

 

My my goals now 

1. Try PVS7 in big dob

2. Figure out focal reducer 

3. Buy 2" H-a for SLR  camera lenses. 


Edited by The Ardent, 06 October 2015 - 04:27 AM.

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#9 cnoct

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Posted 06 October 2015 - 09:44 AM

Monday Oct 5 2015: first day of sunshine after days of rain. I visited Mr. Catapoman, a longtime visual observer. The night was 60% cloudy with poor seeing. I asked him: would you normally set up your scope tonight? "No" was the answer. I pulled out the PVS7+ 50mm SLR lens+ Lumicon night sky filter. "Neat" was his response. We scanned the Milky Way thru the thin clouds. Switched to the stock lens with 13nm H-a. "Now try this" I knew what was coming, and wasn't disappointed when I heard the "jaw drop" sounds from a veteran observer.

 

 

 

Always like to see and hear those responses to Image Intensified Astronomy. 



#10 Eddgie

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Posted 06 October 2015 - 11:10 PM

Nice report.  Yes, I know the sounds having experienced the same thing.

 

Eager to hear your result with dob.   As Cnoct has told me before,  every f/stop you can reduce makes a difference



#11 Eddgie

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Posted 06 October 2015 - 11:21 PM

Oh.  Was in Virginia last night on skyline drive after dark.   Stopped for a quick look with the Micro/ENVIS...

 

I can not fully describe how utterly amazing the view was. 

 

It is almost spiritual experience to sweep along its length.  What was supposed to be five minutes turned into half an hour and I had to get back into the car only with the heaviest of reluctance.

 

Eager to hear NV/dob report.


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#12 The Ardent

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Posted 07 October 2015 - 12:46 AM

Here's the bad news: set up dob at 7:30 under clear skies. Completely overcast at 9. Set up dob again at 11:45 under perfectly clear skies. Completely overcast again at  1am. 

 

The good news: the PVS-7 works fine in the big 18" f/3.5 dob.

 

 I did have another setback with the 2" focal reducer. The PVS-7 with FR, being only 2" dia, slides father into the focuser than possible with a 2" eyepiece. I was almost at focus when I hit a snag. Literally. The headgear clip hits the focuser body !

I'll move the mirror up a little with the Collimation screws this weekend. In the daylight. I need to rinse off the mirror anyway. Other option is a 2" extension tube to push the FR closer to the secondary. 

 

I did order a 1.25" focal reducer combined with a  C-mount to 1.25 adapter:

http://agenaastro.co...al-reducer.html

 

Here is a rundown of observing using Baader 610 LP and Astronomik 13 nm H-a

 

Beatiful star fields  everywhere. About 1/2 degree FOV. Some come at the very edges, not noticeable unless looked for. 

 

M57 - distinctly seen but ghostly transparent with 610 LP. Very distinct with opaque ring with H-a. Loss of faint stars but much more nebula seen. 

 

M 56 - good resolution with 610 LP. Did not try H-a

 

NGC 6905 - good detail but dim with H-a. It's blue visually. Did not try 610

 

M71 and Harvard 20. Good with 610

 

North American - starting to cloud over, but excellent detail with H-a. Brighter knots and dark areas. Much larger than FOV. Pelican too. 

 

NGC 7027- good detail with 610. Lost detail with H-a. It's bright green visually. 

 

NGC 7026 - Wow! A little hamburger! All these years it's been a small, bright,  round nebula visually. Really impressive with H-a. Two ovals in contact wIth  a dark lane.  

 

NGC 6888 the Crescent. Awesome detail on north end. Bright streamers and little black dots in the nebulousity. With a normal eyepiece just a small part is seen. With H-a it's a large oval. Poor RS Cygni , so impressively red visually, just another green star with night vision. 

 

NGC 281 Pac Man. Jus faintest hint of nebula with 610. Big bright raggedy edged nebula with H-a. Thru thick clouds no less. 

 

Many more unidentified H-a regions. Did not take star atlas outside. Next time. 


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#13 The Ardent

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Posted 07 October 2015 - 12:57 AM

Baader 35nm H-a vs Astronomik 12nm H-a

 

Are the nebulae as distinct with the Baader, as they are in the narrower H-a? 

 

Are the the nebulae visible with the Baader? I want my nebulae, and my stars too! 



#14 Vondragonnoggin

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Posted 07 October 2015 - 04:47 AM

I don't know if you read all the info in my previous posts in this thread here, but it explains your results.

 

NGC 6905 spectrum - http://www.astrosurf...063_cbuil_2.png

 

NGC 7027 spectrum - http://www.aanda.org...a1784/img27.gif

 

I posted the spectrum your intensifier responds in as well as what type compositions and filtering work best for different objects and results of 35nm Ha filter compared to narrower Ha filters.

 

The narrower the notch, the greater the signal to noise will be for the specific spectrum emission, i.e. a 3nm Ha filter is going to bring out the Ha notch with much higher contrast and detail than a 12nm filter and a 12nm filter will bring it out in much higher detail than a 35nm, etc.

 

If there are stars emitting wavelengths in blue or green, they will not be seen. The spectrum directly around the notch falls off very rapidly.  

 

If you look at the linked pictures to spectrum of the Blue Flash (NGC 6905), it has very small amount of Ha while emissions in blue are great which the intensifier is not going to pick up the blue strong enough to view. That is why so faint with narrow Ha.

 

The same for NGC 7027 emissions, not enough Ha to get good detail with an intensifier.

 

The effects of contrast boost with longpass filtering make themselves apparent with the amount of skyglow present. Increase in extraneous light sources surrounding the object (the background sky with heavy light pollution) cause the entire view to glow brighter in the intensifier which will wash out other objects emitting only slightly higher luminence in the surrounding wavelengths specific to the object (nebula, open cluster, glob, galaxy, HII region, etc). Putting the longpass on removes a very large portion of unwanted light that caused the intensifier to get brighter in the entire field and then will leave entire field darker, while object sources emitting above that filtered blocked spectrum with then appear with same luminence but with greater contrast showing because of the darker field.

 

To summarize in a very brief summary:

 

Blue, Green stuff bad, red stuff good

35nm results  :undecided:

find high Ha content nebula surrounded with high density stars shining in 600-700nm range and you will have your stars and nebula

610 is a longpass, will not show nebula like a narrowband

 


Edited by Vondragonnoggin, 07 October 2015 - 04:55 AM.


#15 Vondragonnoggin

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Posted 07 October 2015 - 04:53 AM

Dob sounds like it did good. :goodjob:

 

Were you in dark skies or light pollution? Sounds like you had some darker skies.

 

A nice report!



#16 Eddgie

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Posted 07 October 2015 - 06:02 AM

As I recall, hr is near NYC, and one of the reasons he wanted to try night vision was my reports of how much more i was seeing with night vision even under light polluted skies.

 

I think his situation was like mine in that going to dark skies was not practical.

 

I know that when I posted to equipment forum people like Jon said that night vision was not really superior to non boosted if you were under dark skies (which I disagree with because I can see galiexies with more extension and greater detail in the NVD. Micro), but without question I see far more under my light polluted skies.

 

And I think The Ardent was looking for the same benefit.

 

Fingers crossed that he can reach focus with reducer,


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#17 Vondragonnoggin

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Posted 07 October 2015 - 06:32 AM

Dark skies the benefit is still huge. Without the light pollution, the contrast on objects increases that much more. Filters like 610nm will then have very dark field while objects pop even better  than under heavy LP, with good luminance intensity. One of the reasons I keep using a 3nm under full or 3/4 moonlight, rather than my 7nm, although both still show plenty of nebula, is the contrast increase provided by narrower notch.

 

I've only tried under blue zone at my sisters house in Oregon. She lives in a very small town in rural Oregon and you can see the Milky Way naked eye, but not as bright as grey or black zones. Contrast definitely increased under darker skies.

 

I assumed The Ardent might have been under darker skies than white zone because he did not mention the great effect the 610 has over unfiltered. It is more apparent in heavy lp.

 

I can't even imagine what the view looks like through an 18" with NV gear. 6" my biggest scope.

 

If the 18" is an F/4 or very close, a reducer is not really necessary and probably to be avoided going to F/2 with narrowband after fast light cone. It is fine to filter first before super fast focal ratios as is done with camera lenses, but a few have explained that the super fast light cone hitting a regular narrowband could shift the notch to not cover Ha as well. Astrodon and Baader both make some special filters to use with super fast optics to counter this. They are pretty expensive.

 

I just re-read his dob specs - he is at F/3.5 already. If he uses a reducer, he will have decreased performance in narrowband Ha with it already being that fast.


Edited by Vondragonnoggin, 07 October 2015 - 07:06 AM.


#18 Vondragonnoggin

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Posted 07 October 2015 - 06:46 AM

Even Astronomik mentions this performance decrease going faster than F/3 on their 12nm Ha filter description page

 

http://www.astronomi...a-ccd-12nm.html

 

Starizona's page for special Baader narrowband to use with hyperstar F/2 and explains what happens with shift and performance decrease using faster than F/3

 

https://starizona.co...-P3690C837.aspx

 

Bonus - just realized it is probably very appropriate to mention the center wavelength shift with highspeed optics in this thread on filters! :D

 


Edited by Vondragonnoggin, 07 October 2015 - 06:58 AM.


#19 The Ardent

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Posted 07 October 2015 - 09:30 AM

I'm in the city and can't see the Milky Way visually. 

 

I did read your posts (believe me I did) I'm enjoying the night vision exploration. I'm very familiar with the visual appearance of the objects I posted. To make your lessons stick in my thick head, I have to see for myself  :sleuth:

 

I looked at the high speed Baader. No where is mentioned how it works in slower scopes. From the spectrum it looks to have a slightly wider band pass than the 7nm, and shifted to the redder. The 35nm is shifted to the left (blue) of H-a. 

 

The 610 LP is the default filter for the scope. The Lumicon night sky stays on the camera lens. 

 

Whats special about last night I was observing under cloudy conditions where a normal scope is useless. 



#20 Vondragonnoggin

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Posted 07 October 2015 - 09:37 AM

Understood about seeing for yourself. :)

 

My links were really just to read descriptions of center wavelength shift. Not really to buy. With your F/3.5 dob I don't think you should use a reducer and with your F/7 refractor and a reducer, it isn't going to be fast enough to need the highspeed filters. 

 

If you want to try the 35nm, up to you of course, but expect nebulae details diminished compared to your current narrowband, although it does allow a few more stars seen.

 

Baader does have a highspeed 3.5nm, it is about $540

 

Sometimes I research expected targets first and sometimes I just go for trying to view, but there is definitely a lot of spectrum data available if you want to pick best Ha targets beforehand, for instance if you are showing someone else capabilities of NV astronomy and how much difference it can make. 

 

One of these days, I'm going to get to a star party with a couple Nv eyepieces and a few filters and beg for a chance to try it in a really big scope.

 

:D

 

Interesting about night sky Ha and 610 spots as default. Usually doing opposite. 610 in camera lens because of smaller objective and 640 in scope. Until going for fainter galaxies, then I put 610 in scope to allow a little more light through. Either work very good for contrast boost.


Edited by Vondragonnoggin, 07 October 2015 - 09:47 AM.


#21 Vondragonnoggin

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Posted 07 October 2015 - 10:02 AM

Of course, no hard set rules for any of this really. I'm just trying to throw out as much of what I have learned with experimenting for a few years and getting info from others here so I have that publicly available how I come to the best views for me. I figure if I can get awesome results with my older devices and small scopes, it might be that much better for others. YMMV on all of that though really. It's just what has worked for me and the info on how I came to conclusions for my choices.

 

I might pick up a good Ultra spec tube next year and see what the differences are. Awww, who am I kidding, no might about it.

 

:)

 

To tell the truth though, intensifiers just fascinate me too. Really cool technology for really awesome differences viewing and they fit 100% with my style of viewing. A bit of alchemy magic going into each one as they are never 100% identical. Bonus they can be an eyepiece, or handheld, used with astronomy, used for any other night time activities where seeing more helps. So many options of devices and tube types. Unfortunate they are so expensive and import restrictions strict. They completely changed my viewing rewards to be outstanding every time I take one out.


Edited by Vondragonnoggin, 07 October 2015 - 10:19 AM.


#22 PEterW

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Posted 07 October 2015 - 02:25 PM

The horsehead and Rosetta with an 18" and IIE are pretty good... At a Starparty earlier this year. Good transparent night. I left the hardened visual observers to their old glass eyepieces... Why wreck their experience? Showing how an NVD can "turn on the lights" at a very dark sigh is also quite fun too.

 

i would be tempted not to use a reducer on the big dob, maybe get a small scope with similar f-ratio to give a wider field view. Be interested in your experiences on galaxies and globular clusters with the IIE and the big scope... Worth it or not.?!

 

Cheers

 

peter



#23 Eddgie

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Posted 07 October 2015 - 03:14 PM

 maybe get a small scope with similar f-ratio to give a wider field view. 

Cheers

 

peter

 

My standing endorsement for a Comet Catcher (if you can find one).

 

It is as if the scope were made for IIE.    F/3.7.   Swan Nebula was better than I ever saw it in my C14 with glass.    Two degree field, and because of the corrector, very little off axis aberration.

 

What I love most about the Comet Catcher is that I can sit on my front steps and use it in my lap, or cradle it in my arms and hand hold it to sweep across the sky (not for overhead, but for elevations less than about 50-60 degrees).

 

I hand hold it more than I mount it actually.   

 

I would think the old Meade SN-8 or SN-10 would be good with IIE as well, but these are large enough and heavy enough that you start getting into a more serious mount, and this is again one of the great features of the Comet Catcher.  I think it weighs something like 8 lbs with the PVS-7, and it is so fast that even the OMNI 3 + tube in the PVS-7 really comes to life (Vs being in the f/4.9 dob... As Cnoct told me, the focal ratio is indeed a big deal and even the difference between f/3.7 and f/4.9 is quite notiable).


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#24 Eddgie

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Posted 07 October 2015 - 03:22 PM

 

 

To tell the truth though, intensifiers just fascinate me too. Really cool technology for really awesome differences viewing and they fit 100% with my style of viewing. A bit of alchemy magic going into each one as they are never 100% identical. Bonus they can be an eyepiece, or handheld, used with astronomy, used for any other night time activities where seeing more helps. So many options of devices and tube types. Unfortunate they are so expensive and import restrictions strict. They completely changed my viewing rewards to be outstanding every time I take one out.

 

 

Yes.   I agree.  Amazing.  Everyone that sees it for the first time (after the now usually expected expletive) says "It's like being out in the daytime!" or (Surprisingly) "I can see better with this at night than I can see during the day (contact wearers always).

 

I find myself doing far more of my viewing at low powers (1x, 3x, 5X) than I would have thought possible.

 

Had my first look at Hades under dark skies at Lake Placid on Saturday.   It was as if I had never even knew it had existed.   At  3x, it was a glorious sight.   Better than some Messier Clusters at 50x.   

 

Even Plieades was stunning at 3x.  

 

Binoculars were very pale in comparison, even under dark sky.   These targets practically leap out of the sky at you.   

 

I would have never thought that 1x and 3x observing would be so captivating.   So many stars.   

 

I agree, the technology is in itself quite interesting, but using it has been a huge joy far beyond what I had thought possible.

 

Looking to upgrade the PVS-7 to Omni 6 or Omni 7 as soon as I can.


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#25 The Ardent

The Ardent

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Posted 08 October 2015 - 01:42 AM

October 7, 2015
Observing with PVS-7 and 100mm f/7.4 refractor. First time with this scope.

 

Good views with 610nm Longpass filter. FOV around 1 degree.

 

First target was U Lyrae, a deep red faint carbon star. Visually it forms a tiny equilateral triangle with two stars of similar magnitude. In the PVS-7 U Lyr is much brighter than the other two. Faint OC NGC 6791 is visible close by.

 

I tried the 0.5x focal reducer. Unable to reach focus with 2" diagonal.  Need about 1/2 inch more.

 

I removed the diagonal and tried straight thru. Works with a 2" extension tube. Nice wide 2-degree FOV with a teeny bit of vignetting. Great views of Stock-2, Double Cluster, M31, 32, and 110. The last was much brighter than expected.

 

Advantage of straight thru: better brighter image, correct view orientation.
Disadvantage: neck pain and tripod hugging.
I can't wait to try that 1.25" c-adapter + .5 focal reducer combo.

 

Replaced the diagonal for viewing at f/7.4

 

M33 - faint, barely visible with 32mm eyepiece against bright urban sky. With PVS-7 and 610 LP : very slight enhancement. Worse with H-a. I hoped one of the H-a regions might light up, but just saw the core. Barely.

 

M76 - faint bi-lobed with H-a. Very faint with 610. No structure.

 

M103, NGC 663, 654, 659. Very nice with 610 LP, but need more magnification.

 

Minkowski 1-92 , The Footprint Nebula. Visible as a tiny faint star w/ 610 LP . Too dim with H-a.

 

PK 064+5.1 , Campbell's Hydrogen Star. Bright and slightly non-stellar with 610 LP. Similar view as visual in 18" dob.. Crazy bright with H-a. As bright as 9 Cyg. Visually it's nebula appears orange from H-a.

 

NGC 6960, Western Veil. Not visible with 610 LP or H-a.

NGC 6995-6992, Eastern Veil. Barely visible with 610 LP. Similar to visual unfiltered view in 4". With H-a it's brighter with a little structure, similar to a visual view with OIII fiLter in same aperture.

 

With Cygnus losing altitude I decided to return to f/3.7 straight-thru viewing. The skies are increasingly hazy, and some clouds are coming in from the north.

 

The Western Veil is now faintly visible with H-a. The Eastern is much brighter with improved detail. NGC 6974 is now easily visible.

 

The Gamma Cygni clouds are large and bright with H-a.

 

North American, Pelican have detail but not like in the 18" dob.

 

NGC 7027 and 7026 are just stars at this low power. No detail or disk to be seen.

 

IC 5146, the Coccoon. Visible as a faded round patch with 2 faint "eyes" with H-a. Barnard 168 was not seen. In a visual scope the reverse is true.

 

clouds came in fast. It's like they resent night vision!




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