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Future NV Setup...

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#1 stargazer434

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Posted 19 February 2019 - 01:34 PM

Hello All-

 

After moving away from hobby astronomy about a decade ago (other than enjoying some hydrogen-alpha solar observing), I have come across this concept of night vision astronomy which has reignited my personal interest.  My main reason for the leaving the hobby was exhausting my naked eye observing options from light polluted skies and not having the time to either travel to dark sky locations or pursue conventional astrophotography.

 

This NV concept seems like it is a game changer, so I have been trying to research the best way to approach this and go all in.

 

I sounds like I would want some kind of high-quality gen 3 monocular with white phosphorus (ideally) that has easy adapters for connecting in a prime focus manner to camera lenses, astrographs, etc.

 

It seems like the NVD Micro is the best fit for this:

http://nvdevices.com...sion-monocular/

 

Any other NV suggestions appreciated?

 

I would then probably want to get some compatible UHC/Hydrogen Alpha/etc. filters

 

Any favorite filters for current NV?

 

I think I would like to keep it setup hand-held for low-power viewing initially.

 

Any favorite standard objective lenses, f-2 finder scopes, telephoto lenses?

 

Eventually, I think I would pick up a small astrograph refractor and az/mount that I would clamp to the roof hatch of my expedition truck for my observing sessions.

 

Would this be overkill or the seemingly perfect portable complement?  Borg 55 F-3.6 seems perfect?  Other astrographs?

 

Thanks in advance for your advice!

John


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#2 chemisted

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Posted 19 February 2019 - 01:53 PM

Have you read Peter's very nice intro site:   http://pwang.io/hobb...ro/nightvision/  ?



#3 bobhen

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Posted 19 February 2019 - 01:57 PM

HERE is a website with lots of info about intensifiers and filters, etc. Start here.

 

Camera lenses or 50-60mm guide scopes can be hand held and are nice for low power, extremely wide field viewing.

 

In addition to the above, I would suggest a small refractor or Newtonian. I wouldn’t go smaller than 6” for a Newtonian or 100mm for a refractor or you’ll be too close to the views provided by the camera lenses or guide scope options.

 

80, 102 and 120mm fast F5 achromats work very well with filters. Newtonians can be purchased at F5 or lower as well.

 

Keep in mind that just about any telescope will work with an intensifier, it just depends on what objects you want to view and your location and your potability requirements, etc. 

 

Bob



#4 Jeff Morgan

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Posted 19 February 2019 - 02:54 PM

This NV concept seems like it is a game changer, so I have been trying to research the best way to approach this and go all in.

 

 

Oh, it is definitely that! And on so many levels.

 

I sounds like I would want some kind of high-quality gen 3 monocular with white phosphorus (ideally) that has easy adapters for connecting in a prime focus manner to camera lenses, astrographs, etc.

 

 

Keep in mind the color of the phosphor tube is more a preference issue not a performance issue.

 

A C-mount device is definitely more flexible and user-friendly while still preserving the afocal option.

 

OTOH if the your only choice is device without a removable objective, don't let that kill the deal.

 

It seems like the NVD Micro is the best fit for this:

http://nvdevices.com...sion-monocular/

 

Any other NV suggestions appreciated?

 

The Micro gets great reviews from owners. I went with a Mod 3C for the manual gain (personal preference). The PVS-14 would also work, but the objective lens is not removable.

 

I would then probably want to get some compatible UHC/Hydrogen Alpha/etc. filters

 

Any favorite filters for current NV?

 

Long pass and H-alpha. Popular choices are 685nm and 640nm (long pass) and 12nm and something in the 5nm-7nm range. Unfortunately, getting just one size (1.25" or 2") creates limits so you eventually end up getting both $izes.

 

Standard visual (nebular) filters have turned out to be largely (if not totally) ineffective for NV.

 

Any favorite standard objective lenses, f-2 finder scopes, telephoto lenses?

 

 

Telephoto lenses rock! C-mount to telephoto adapters run $20 ballpark. I'm currently using 50mm, 135mm, and 300mm. Plan to add 200mm and 85mm.

 

To use filters you can either epoxy a 1.25" ring inside the adapter, or get an adapter to thread 2" filters over the front of the telephoto (135mm and smaller).

 

Eventually, I think I would pick up a small astrograph refractor and az/mount that I would clamp to the roof hatch of my expedition truck for my observing sessions.

 

Would this be overkill or the seemingly perfect portable complement?  Borg 55 F-3.6 seems perfect?  Other astrographs?

 

 

Sounds like an excellent plan. There are many great options out there. Be sure to pick up the correct nose pieces. For C-mount either (or both) of these:

 

http://scopestuff.com/ss_c2b1.htm

http://scopestuff.com/ss_c2bf.htm

 

And for afocal:

 

https://tnvc.com/sho...ronomy-adapter/

 

Plus of course the correct eyepiece for afocal. The Tele Vue 55 Plossl is the go-to choice for maximum effective speed. The 41 Panoptic has gotten some good reports also.



#5 stargazer434

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Posted 19 February 2019 - 05:15 PM

Wow, thanks everyone for your quick responses.  Peter's intro was great.  I had not seen that before. 

 

@Bob.  Definitely going to get one of the those fast achromats with a simple a/z mount.  So cost effective.  I assume chromatic aberration is not a big factor when using NV?  Think I will skip the camera lenses.

 

@Jeff. Great details.  Glad that it sounds like I am on the right track.  I think I'd like the manual gain on the 3C/  Thanks for the tip to skip the UHC filters.  Also all the links to the adapters.

 

Now to figure out what I need to liquidate to jump in, haha


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#6 bobhen

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Posted 19 February 2019 - 06:19 PM

Wow, thanks everyone for your quick responses.  Peter's intro was great.  I had not seen that before. 

 

@Bob.  Definitely going to get one of the those fast achromats with a simple a/z mount.  So cost effective.  I assume chromatic aberration is not a big factor when using NV?  Think I will skip the camera lenses.

 

@Jeff. Great details.  Glad that it sounds like I am on the right track.  I think I'd like the manual gain on the 3C/  Thanks for the tip to skip the UHC filters.  Also all the links to the adapters.

 

Now to figure out what I need to liquidate to jump in, haha

 

If you get a fast achromat, you will HAVE to use filters (a Pass filter for non-nebula objects and a Ha filter for nebula) but most NV observing is done with filters anyway.

 

If you purchase one of the inexpensive 80, 102 or 120mm F5 refractors made by Synta (Sky Watcher) and you want to use a 2" .7 reducer or 2" diagonal you will need to purchase a GSO, 2” focuser as well in order to accommodate in-focus travel. Otherwise a 1.25- inch diagonal used with the scope's native F5 and with the scope's standard focuser will work. Don’t worry all will be worth it!

 

Below is one of the scopes I use. It’s my 102mm F5 Celestron/Synta 102mm F5 refractor with the Micro Intensifier in the diagonal and a GSO focuser – a great combination. I use this system a lot more than my 50mm guide scope, even though that combination can be hand-held.

 

Bob

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#7 Eddgie

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Posted 19 February 2019 - 06:20 PM

While I have a Micro and love it, most people here will recommend the Mod 3 monocular in C mount, and I would do the same.

 

https://www.ultimate...m3m-c-gc-uw.htm

 

The Micro does not have gain control.  Now I live fine without gain control on my Micro, but I have two Mod 3s and my Mod 3s have gain control.

 

You can get the Mod 3 from Ultimate Night Vision and TNVC.   

 

Again, not that the Micro is bad.  I love my Micro, but I recommend the Mod 3 with gain for astronomy.



#8 Eddgie

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Posted 19 February 2019 - 06:23 PM

And a word of caution.   The pictures you will see at Ultimate and TNVC show the Mod 3 with an objective, but it does not come with one.   Most people will use a 25mm CCTV camera lens for 1x, or an SLR lens.

 

The Micro sold by NVDevices does come with a CCTV lens, but again, these are not all that expensive, and NVDevices is mostly a thin film tube shop (not that this is bad, a Micro with a ULT Green tube will perform as well as many of the filmless tubes out there).

 

Ultimate and TNVC both deal a lot in filmless tubes. 



#9 stargazer434

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Posted 19 February 2019 - 08:05 PM

If you get a fast achromat, you will HAVE to use filters (a Pass filter for non-nebula objects and a Ha filter for nebula) but most NV observing is done with filters anyway.

 

If you purchase one of the inexpensive 80, 102 or 120mm F5 refractors made by Synta (Sky Watcher) and you want to use a 2" .7 reducer or 2" diagonal you will need to purchase a GSO, 2” focuser as well in order to accommodate in-focus travel. Otherwise a 1.25- inch diagonal used with the scope's native F5 and with the scope's standard focuser will work. Don’t worry all will be worth it!

 

Below is one of the scopes I use. It’s my 102mm F5 Celestron/Synta 102mm F5 refractor with the Micro Intensifier in the diagonal and a GSO focuser – a great combination. I use this system a lot more than my 50mm guide scope, even though that combination can be hand-held.

 

Bob

Thanks for sharing, Bob!  That looks like a great setup.  What would you think of using this scope:

https://www.stellarv...e-black-f080m3/

80mm, f-3.75, 2" helical focuser

 

Again, not that the Micro is bad.  I love my Micro, but I recommend the Mod 3 with gain for astronomy.

I'm sold.  I would definitely like to be able to adjust the gain.



#10 Mazerski

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Posted 19 February 2019 - 08:05 PM

John,

 

If you need photos: not sure if they will remain in the attached order...

 

Photo 1:

Mod3 and PVS-7 both are C-Mount (REQUIRED due to versatility) - shown with ENVIS lens. If you get the ENVIS, you can use the RAF adapter (the thin ring leaning against the PVS-7)

The ring is in the MOD 3 ENVIS as you can see filter screwed in. This allows hand-held 1x (and 3x with a special lens and adapter - not included in these photos)

 

Photo 2:

The Mod3 has the ScopeStuff C-Mount to 1.25" adapter... you can see a filter on the right end of adapter - this allows the Mod3 to be used with a 50mm CCD finder as well as into a 1.25" focuser of scope

 

Photo 3:

ScopeStuff makes a 2" C-Mount adapter... has provision inside for 1.25" filter to screw in (looks purple) and if you want, a 2" focal reducer can screw on

 

Photo 4: 

Again, you want C-Mount... the larger C-Mount adapter is screwed into the Mod3. I have an Obsession 15" Classic and this 2" adapter MUST be used with the Mod3 to achieve focus

 

Phot 5:

I use hand-held with Nikon Nikkor lenses (others use different lens types) which requires the Nikon F --> C (Mount) adapter. This works great. I have multiple adapters with filters inside to for easy viewing. 

 

Filters... I live on the east coast. The Baader 610nm IR is useless as it lets in way too much light. I do use:

 

Astronomik 642nm IR, 6nm Ha, 12nm Ha

Baader 685nm IR, 7nm Ha

 

 

 

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#11 bobhen

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Posted 20 February 2019 - 08:19 AM

Thanks for sharing, Bob!  That looks like a great setup.  What would you think of using this scope:

https://www.stellarv...e-black-f080m3/

80mm, f-3.75, 2" helical focuser

 

I'm sold.  I would definitely like to be able to adjust the gain.

My guess is with the scope linked that you won't be able to reach focus with an intensifier, and definitely not with a reducer.

 

In the 80mm size I think you would be better off using one of the regular F5 or F6 80mm telescopes. However, if you use camera lenses or a 50mm guide scope for extreme low power viewing then I would skip the 80mm size and jump to 102mm. 

 

Bob



#12 stargazer434

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Posted 20 February 2019 - 05:50 PM

This just popped up on ebay yesterday:

 

https://www.ebay.com...353.m1438.l2649

 

It is a mod 3 green film adjustable gain c-mount gen 3.  Still look worthwhile?  What would be a fair offer price?


Edited by stargazer434, 20 February 2019 - 05:57 PM.


#13 Mazerski

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Posted 20 February 2019 - 06:21 PM

I have been trying to purchase a 2nd PVS7 and finding a test data sheet of the tube specs seems impossible. So, with the unit on eBay, I would ask if they have it. Other CN users have much more knowledge than I do on tubes and tube iterations... this site may be helpful:

 

https://www.ar15.com...nces/18-317705/

 

The units I have are "filmless" vs. thin filmed and have never looked thru thin filmed.



#14 Eddgie

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Posted 20 February 2019 - 07:15 PM

If the tube in a PVS-7 is a contract tube, it will not have specs.  The tube should meet minimum specs for the tube type. For a PVS-7 10130 D/UV, that will be a minimum SN of 21 with EBI max of 2.5.

 

There is an ongoing debate about whether an Omni VII PVS-7 tube is performing at the stated specs from the table on AR15, but my experience is that all PVS-7 D/UVs are pretty much Omni IV/V performance.  I have a brand new Omni VII contract 10130 D/UV tube in my PVS-7 A and I have an 10160C/AVS-6 tube in my Micro, and it is dead easy to see that the Omni AVS-6 tube has much lower noise than the Omni VII PVS-7 tube.

 

So, if it is a 10160 D/UV, there will never be a spec sheet with it unless it was tested by someone like Ed Wilcox.   You can get minimum specs for the model, but that is it.

 

But the way, I a going to sell the PVS-7 A with the new Omni VII tube, so if anyone is looking, I will probably post it later this week.  



#15 11769

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Posted 20 February 2019 - 10:12 PM

This just popped up on ebay yesterday:

 

https://www.ebay.com...353.m1438.l2649

 

It is a mod 3 green film adjustable gain c-mount gen 3.  Still look worthwhile?  What would be a fair offer price?

Thin film tubes are not necessarily any worse than filmless, just that some filmless tubes can be better. L3 produces many filmless tubes that have absolutely horrible specs that most thin film and even most thick film tubes can routinely beat. It's only the relatively few tubes on the right hand side of that distribution that are the envy of many. The minimums on Omni 7 tubes, like the one in that listing, are very good to begin with (SNR of 28 min.) and I have had a few Omni 7 tubes that keep up and sometimes outperform a filmless tube that has specs that are in the "envy of many" category. 

 

Have dealt with that seller many times and have never been disappointed, if anything, he has always gone the extra mile. He also sold a PVS-14 to a friend of mine that got the NV disease and he was more than content. Will send you his contact info in case he's open to saving you some money. 


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#16 stargazer434

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Posted 21 February 2019 - 01:12 PM

Well, I have secured that mod 3 green film, adjustable-gain, c-mount intensifier listed above!  Thanks to @11789 and Paul for securing a good price.  Now, I can decide on the rest of the requirements. 

 

Since I will always be staying visual does anyone see a down side in staying 1.25" for accessories?

 

I am thinking of this setup:

 

Mod-3 -> c-mount to 1.25" adapter -> 1.25" filter wheel with 685/640/12/7/5nm filters -> Orion 120mm F-5 refractor (I figure why not go for a little more aperture when DSOs are my interest)

 

Any recommendations for a sturdy budget alt-az for this setup?  Also, I'm trying to also trying to find a table top pillar w clamp for the base instead of a tripod.  I really need to keep this setup compact for small spaces.


Edited by stargazer434, 21 February 2019 - 01:24 PM.


#17 Vondragonnoggin

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Posted 21 February 2019 - 01:34 PM

Well, I have secured that mod 3 green film, adjustable-gain, c-mount intensifier listed above!  Thanks to @11789 and Paul for securing a good price.  Now, I can decide on the rest of the requirements. 

 

Since I will always be staying visual does anyone see a down side in staying 1.25" for accessories?

 

I am thinking of this setup:

 

Mod-3 -> c-mount to 1.25" adapter -> 1.25" filter wheel with 685/640/12/7/5nm filters -> Orion 120mm F-5 refractor (I figure why not go for a little more aperture when DSOs are my interest)

 

Any recommendations for a sturdy budget alt-az for this setup?

If you are going to use a stock focuser on the 120ST, the filter wheel might not come to focus. It definitely won’t come to focus if you decide to use a focal reducer screwed on the nosepiece. You might consider a ScopeStuff 2” c-Mount nosepiece with inset 1.25” filter threads. It also has 2” threads on the outside. This way you can use your 1.25” filters and use a 2” Antares .5x or .7x reducer with it. It is exactly the one Mazerski pictured in a previous post.  waytogo.gif

 

Not sure about the mod 3 housing, but I have 4 NV devices that use 18mm tubes and all of them vignette with a 1.25” reducer in.

 

The difference the reducer makes for me in my 120ST in primarily white zone (some red if looking up over the ocean area. Ocean to one side, Heavy LP of Santa Ana Disneyland etc on the other side) is seeing the Flame nebula at F/5 or using the .5x reducer on the nosepiece (it would screw on the outside 2” threads while your filter gets screwed in the inset 1.25” threads) I can then see IC434 lit up enough to get some detail on the Horsehead nebula.

 

multiple objects present more detail with reducer in when viewing nebulae in narrowband Ha.

 

As long as the reducer is the 2” version, I have not experienced vignetting with 18mm tubes. 

 

Its not the full .5x reduction but it’s enough to substantially brighten up the view for more threshold objects.

 

I replaced the stock focuser in the 120ST for a TS Monorail linear bearing focuser. It’s the same as the GSO linear bearing focuser. ScopeStuff has these GSO 2” Crayford or Linear Bearing focusers. The adapter plate for the GSO focusers is substantially shorter than the stock adapter for stock focuser. Might even give enough backfocus for a filter wheel but probably not enough for a filter wheel AND a reducer. CN Member cw00 uses the Orion 120ST and did the changeover to the GSO and showed some good pictures of how much shorter it is with GSO adapter and 2” Crayford. 

 

Here is is a link to his post with picture of the two focusers and showing how much shorter the GSO is:

 

https://www.cloudyni...back/?p=6917757

 

You might find the whole thread interesting as it shows his Orion 120ST and pics of my Skywatcher 120ST and linear bearing focuser.

 

Mounting for my 120ST is on a Vanguard Auctus Plus AT3 Tripod with crank adjustable center column (40lb capacity tripod - Also have a Manfrotto 117b crank adjustable center column tripod at 40lb capacity. Manfrotto built a little better, but Vanguard has worked for years) with a Stellarvue M2 Head with steering arm. Discmount DM4 would be a nice option also.

 

I only have manual alt-az mounts though. The scope with rings and mod 3 would probably be all of 10lbs. I like to go a little overmounted for steadiness.

 

I also use an adjustable seat height observing chair. I have the Smart Seat Pro from SmartAstronomy. I think other vendors sell it under a different name. Between the my seat height adjustment and center column adjustment, I am pretty much always comfortable when viewing and can relax to study objects.


Edited by Vondragonnoggin, 21 February 2019 - 02:14 PM.

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#18 Jeff Morgan

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Posted 21 February 2019 - 04:34 PM

Well, I have secured that mod 3 green film, adjustable-gain, c-mount intensifier listed above!  Thanks to @11789 and Paul for securing a good price.  Now, I can decide on the rest of the requirements.

 

Congratulations!



#19 Jeff Morgan

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Posted 21 February 2019 - 04:42 PM

If you are going to use a stock focuser on the 120ST, the filter wheel might not come to focus. It definitely won’t come to focus if you decide to use a focal reducer screwed on the nosepiece. You might consider a ScopeStuff 2” c-Mount nosepiece with inset 1.25” filter threads. It also has 2” threads on the outside. This way you can use your 1.25” filters and use a 2” Antares .5x or .7x reducer with it. It is exactly the one Mazerski pictured in a previous post.  waytogo.gif

 

+ 1 on the ScopeStuff 2" adapter.

 

A filter wheel would be a nice convenience, but it eats up precious back focus distance. And they can be physically awkward too.

 

And consider that the normal tendency is to see a need for an extensive filter collection (just like we all do with eyepieces lol.gif ).

 

The reality is you will probably own two long pass filters and use one predominantly.

 

About the same situation with h-alpha.


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#20 Vondragonnoggin

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Posted 21 February 2019 - 05:21 PM

That’s true.

 

Its come down to the 3nm Ha and the 640nm longpass for me. Rarely I go for something different. 



#21 stargazer434

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Posted 21 February 2019 - 06:14 PM

This continues to snowball nicely and I appreciate all the pro tips everyone! 

 

Sounds like I should elbow the filterwheel idea as expensive overkill and to avoid back travel focuser problems because I will want a good 0.5 reducer on whichever scope I choose in the end.

 

Sounds like the Orion 120mm F-5 is still the budget scope to beat.  Any other refractors folks would recommend new or used?  I think I will hold off on upgrading the focuser right away as long as it is workable at least.

 

How about this as the revised overall setup and parts list?

 

Orion 120mm F-5 Scope and Mounting Hardware

Orion VersaGo II Alt Az Mount (seems sturdy enough?)

2" Antares 0.5x Focal Reducer (speed and brighten things up)

1.25" 2" Scopestuff GSO 99% Diagonal

ScopeStuff 2" C-mount Adapter (allows 1.25" filters to be screwed on)

2 filters to start with: 3nm Ha and 640nm Long Pass (which makers do folks like?)

Mod 3 intensifier


Edited by stargazer434, 21 February 2019 - 06:49 PM.

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#22 Vondragonnoggin

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Posted 21 February 2019 - 06:32 PM

This continues to snowball nicely and I appreciate all the pro tips everyone! 

 

Sounds like I should elbow the filterwheel idea as expensive overkill and to avoid back travel focuser problems because I will want a good 0.5 reducer on whichever scope I choose in the end.

 

Sounds like the Orion 120mm F-5 is still the budget scope to beat.  Any other refractors folks would recommend new or used?  I think I will hold off on upgrading the focuser right away as long as it is workable at least.

 

How about this as the revised overall setup and parts list?

 

Orion 120mm F-5 Scope and Mounting Hardware

Orion VersaGo II Alt Az Mount (seems sturdy enough?)

2" Antares 0.5x Focal Reducer (speed and brighten things up)

1.25" Scopestuff GSO 99% Diagonal

ScopeStuff 2" C-mount Adapter (allows 1.25" filters to be screwed on)

2 filters to start with: 3nm Ha and 640nm Long Pass (which makers do folks like?)

Mod 3 intensifier

You’ll need a 2” diagonal for the 2” nosepiece from ScopeStuff 

 

Probably wont find a 3nm Ha thats mounted. I have an Omega 3nm but he stopped making the 3nm recently and makes a 4.5nm as lowest. Most people like a 5nm Astrodon or 7nm Baader or even a 6nm Astronomik. The narrower the notch, the more contrast it brings but when you are looking at max 2nm difference between 7nm and 5nm the contrast boost of the 5nm won’t be much over the 7nm. Pretty sure you would notice it though. At that point I think it’s what fits your budget. Astrodon probably the most expensive of the three. I would happily use any of those. I have a Baader 7nm myself and got it before finding the 3nm. Tons of detail with 7nm. Again, pick what fits your budget and then just enjoy it. All good filters.

 

My 640nm is the Lumicon Night Sky H-Alpha filter. Advertised as an Ha filter but really a longpass 640nm according to filter curves. Maybe someone else knows of another around that wavelength as an alternative to buy. I think Mazerski mentioned he had a 642nm, so ask him about it.

 

The rest looks good. If you don’t come to focus with the 2” .5x reducer, think about that GSO upgrade. As you can see from the picture I linked to, it substantially shortens the scope and will give you enough backfocus to use the reducer with room to spare. VersaGo II should be fine, but probably most comfortable with a good adjustable height chair. YMMV

 

Edit - I use 2” filters so maybe Astrodon has a 3nm in 1.25” format mounted. Do not get a Baader high speed filter at 3.5nm. Unless you are using it after a super fast objective like in the F/1.2 range, the high speed filters have been tested as not so great with NV use. Astrodon regular 3nm would be fine. They are pretty expensive so if you’d prefer to go with 5, 6, or 7nm from various manufacturers listed, then just grab what fits the budget. I think 5, 6, and 7nm probably the most used by forum members here. 

 

Any fairly fast refractor is a good place to start. I think things start opening up for being good as grab n go and for enough light gathering to catch large structures and get the most from Richfield viewing at anywhere from 72mm to 120mm

 

My 6” refractor has beautiful views but it is a litttle beast in weight and takes a good hour for cooldown 

 

If you went for an apochromatic fast refractor, you would have a nice all around viewing scope for NV and regular eyepiece use. The 120ST is fun with regular eyepieces for low and medium powers on DSO’s but would not be a scope of choice for me for planets. I have an MCT for planets though so I bought the 120ST with intent on using for NV Richfield viewing. Sometimes barlow the NV device for globs and PN’s too.


Edited by Vondragonnoggin, 21 February 2019 - 06:49 PM.

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#23 Doug Culbertson

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Posted 21 February 2019 - 06:38 PM

Just my $.02

While you’re getting the 2” .5x reducer you might as well get the .7x as well. I use both, though I use the .7x more. IMO, 3nm is pretty narrow. Depending upon the night, I actually tend to use my 12nm more often than my 6nm, but I’ve never wished for any narrower than the 6nm. FWIW, both of mine are Astronomik filters.

When I had an Orion 120ST the VersaGo II was a perfect match. Put out a wanted ad for the scope, unless you are in a hurry. I got mine within a week of posting an ad, and it came with a better focuser, tube rings and a dovetail for the price of a new one without anything.

Unless I am missing something, you should probably get a 2” diagonal instead of the 1.25” if you are going to use the ScopeStuff c-mount/2” adapter. The 2” adapter isn’t going to work with a 1.25” diagonal.

#24 Vondragonnoggin

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Posted 21 February 2019 - 07:11 PM

IMO, 3nm is pretty narrow. Depending upon the night, I actually tend to use my 12nm more often than my 6nm, but I’ve never wished for any narrower than the 6nm. FWIW, both of mine are Astronomik filters.

I guess everyone has different tastes. Never seen another 3nm filter user on here so don’t know who might like it or not. It’s my preference in light pollution and particularly when the moon is up.

 

I think the 5, 6, or 7nm is fine for narrowest Ha for most people and that’s why I mentioned it.

 

shrug.gif

 

It it was just by chance too on the 3nm because Omega filters had the 2” 3nm for $140

I couldn’t resist after paying nearly $400 for a 2” Baader 7nm. It turned out to be my favorite.

 

its definitely a contrast boost, but more like the descriptions of contrast boost between 5nm and 7nm that Shams42 and GeezerGazer wrote about in their article. Not in your face, but it’s there. Particularly under full moon.

 

 


Edited by Vondragonnoggin, 21 February 2019 - 07:26 PM.


#25 Vondragonnoggin

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Posted 21 February 2019 - 08:20 PM

Maybe some important things to consider when debating how narrow to go in your Ha notch is discussed in the following thread which talks about falloff Of filter notch, bandwidth shift and shows som photographic examples of it as well as the contrast boost between narrower 5nm and a 12nm:

 

https://www.cloudyni...-filters/page-3

 

There are some rewards and some penalties for going narrower. Good info in that thread.

 

This difference in falloff as well as differences in contrast are reasons why I have not sold my 7nm, 12nm, or even 35nm Ha filters

 

Just as use with my mak 150 at F/7 to F/12 is a reason I have not sold my 610nm. In the long focal length use of the mak, I prefer to let more light in for clusters and globs while still blocking some light pollution where in the smaller and faster 120ST I find the 640nm more desirable for a longpass.

 

A lot can depend on site you are at and amount of lp, which scope focal length and what aperture you have. Definitely a varied use of equipment here.


Edited by Vondragonnoggin, 21 February 2019 - 08:30 PM.



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