Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Newbie NV questions

  • Please log in to reply
61 replies to this topic

#26 Gschnettler

Gschnettler

    Messenger

  • -----
  • topic starter
  • Posts: 404
  • Joined: 14 Jul 2020
  • Loc: Cincinnati Ohio

Posted 07 April 2021 - 01:19 PM

I have Morpheus eyepieces and I have to use them in 1.25” mode in my Dob. If I try to use them as 2” then I don’t have enough backfocus. Does that indicate that I’ll likely need to use the PVS-7 as a 1.25” as well?

Also, is the binocular view considered to be a good thing for astronomical use?

#27 Gschnettler

Gschnettler

    Messenger

  • -----
  • topic starter
  • Posts: 404
  • Joined: 14 Jul 2020
  • Loc: Cincinnati Ohio

Posted 07 April 2021 - 01:24 PM

Also...what is PVS-7? Is that a standard that the military defined and then multiple companies can manufacture it? Or is it a product from a specific company?

Also, can you upgrade it by swapping out the tube...for example from green to white? Or maybe a tube with more sensitivity?

#28 Gschnettler

Gschnettler

    Messenger

  • -----
  • topic starter
  • Posts: 404
  • Joined: 14 Jul 2020
  • Loc: Cincinnati Ohio

Posted 07 April 2021 - 01:51 PM

One more question. I have read that night vision devices help you see even in light polluted areas. Does that apply even if the light pollution is coming from LED bulbs?

#29 Jeff Morgan

Jeff Morgan

    Voyager 1

  • *****
  • Posts: 13,439
  • Joined: 28 Sep 2003
  • Loc: Prescott, AZ

Posted 07 April 2021 - 07:32 PM

1) Going 2" (using the second c-mount adapter) allows you to insert the PVS-7 deeper into the focuser, if that is necessary for you to achieve focus.  Adding a 1.25" adapter to the c-mount adapter pushes you further out.  

 

That in and of itself is a great reason.

 

Another great reason is the Antares 2" focal reducer (0.7x). Great piece of NV gear!

 

Eventually operational flexibility will push you into both sizes - adapters and filters. (BTW, the ScopeStuff 2" C-mount adapter is threaded for both sizes.)

 

It's really worth the extra $25 to get the 1.25" format c-mount adapter. Both for Barlow/Powermate use and the occasional scope that only has a 1.25" focuser.

 

The duplicating of filters stings the wallet a bit more, but the flexibility will be appreciated long after the sting to the wallet has faded.



#30 a__l

a__l

    Gemini

  • -----
  • Posts: 3,168
  • Joined: 24 Nov 2007

Posted 07 April 2021 - 11:01 PM

One more question. I have read that night vision devices help you see even in light polluted areas. Does that apply even if the light pollution is coming from LED bulbs?

You will have lens flares  (and/or filters). You have a rising background of light pollution. Therefore, the general rule applies everywhere. The less light pollution the better. There is an improvement with the use of filters, but miracles do not happen.


Edited by a__l, 07 April 2021 - 11:04 PM.


#31 a__l

a__l

    Gemini

  • -----
  • Posts: 3,168
  • Joined: 24 Nov 2007

Posted 07 April 2021 - 11:15 PM

I have Morpheus eyepieces and I have to use them in 1.25” mode in my Dob. If I try to use them as 2” then I don’t have enough backfocus. Does that indicate that I’ll likely need to use the PVS-7 as a 1.25” as well?

 

In general, this is the wrong approach. You need the fastest optics possible for your Dob.
The field of view of an NV lens is usually limited to 40 degrees. You need to use afocal TV67 (maximum focal length, maximum field and result fast maximum). This is standard 2".


Edited by a__l, 07 April 2021 - 11:22 PM.


#32 shohin

shohin

    Vostok 1

  • *****
  • Posts: 191
  • Joined: 06 Oct 2016
  • Loc: Socal

Posted 08 April 2021 - 03:14 AM

I have Morpheus eyepieces and I have to use them in 1.25” mode in my Dob. If I try to use them as 2” then I don’t have enough backfocus. Does that indicate that I’ll likely need to use the PVS-7 as a 1.25” as well?

Also, is the binocular view considered to be a good thing for astronomical use?

To clarify, there are two ways of configuring the PVS-7 for a 2" focuser.

 

1) Use the second PVS-7 to c-mount adapter and insert up to the third ledge.  This gives you the deepest mount.

 

2) Use either of the PVS-7 to c-mount adapters, plus a Scopestuff c-mount to 2" eyepiece barrel adapter.  This pushes you further out.  http://www.scopestuff.com/ss_c2bf.htm

 

To configure for 1.25" focuser you can use either of the PVS-7 to c-mount adapters, plus a c-mount to 1.25" eyepiece barrel adapter.

 

I don't know enough about Morpheus vs. c-mount focal planes to be able to reliably tell you which configurations will work for your dob.  My semi-uneducated guess would be 2" method #2, or 1.25".  If you wanted to cover all your bases you could buy the second PVS-7 to c-mount adapter, and both the 1.25" and 2" eyepiece barrel adapters.  Not the cheapest route (because of that superfluous commercial c-mount lens that comes with the second adapter) but would give you the most flexibility in mounting up your PVS-7 to different OTAs.

 

Also...what is PVS-7? Is that a standard that the military defined and then multiple companies can manufacture it? Or is it a product from a specific company?

Also, can you upgrade it by swapping out the tube...for example from green to white? Or maybe a tube with more sensitivity?

I'm not sure how many companies exist that actually manufacture the individual bits 'n' pieces, but there are multiple value added retailers that assemble the pieces and sell the complete units.

 

Yes you can upgrade the tube.  Remove the nosepiece/lens and the tube comes right out.



#33 bobhen

bobhen

    Fly Me to the Moon

  • *****
  • Posts: 5,388
  • Joined: 25 Jun 2005

Posted 08 April 2021 - 05:46 AM

There is an improvement with the use of filters, but miracles do not happen.

Night Vision is absolutely a techno-miracle.

 

I live in an extremely light polluted location just outside of Philadelphia with all types of light pollution; from strong local lights to the multiple light sources from a large city like Philadelphia to urban sprawl to one of the largest malls on the east coast just 3 miles away. That I can "easily" see the Horsehead Nebula and even spot the brighter sections of Barnard’s Loop is only possible through the “miracle” of image amplification provided by an image intensifier, without which these and many other objects would not be observable.

 

Bob


  • Jeff Morgan likes this

#34 Jeff Morgan

Jeff Morgan

    Voyager 1

  • *****
  • Posts: 13,439
  • Joined: 28 Sep 2003
  • Loc: Prescott, AZ

Posted 08 April 2021 - 03:14 PM

Night Vision is absolutely a techno-miracle.

 

I live in an extremely light polluted location just outside of Philadelphia with all types of light pollution; from strong local lights to the multiple light sources from a large city like Philadelphia to urban sprawl to one of the largest malls on the east coast just 3 miles away. That I can "easily" see the Horsehead Nebula and even spot the brighter sections of Barnard’s Loop is only possible through the “miracle” of image amplification provided by an image intensifier, without which these and many other objects would not be observable.

 

Bob

 

waytogo.gif Absolutely.

 

The best performance - with any of our astro gear - is to get to a dark sky. That will always be true.

 

But with the relentless spread of light pollution, one has to go farther and farther from home, which translates directly into fewer and fewer opportunities to observe.

 

Even for the retiree, that is a formidable obstacle. For the rest of us with work, family, and (non-astro) friends, forget about it.

 

On the other forums, the Traditionalists say the answer to fight light pollution is "more aperture". That is the perhaps the most bone-headed advice given out on this website. Light pollution effectively neuters those big mirrors, leaving the base problem unsolved.

 

OTOH, electronic astronomy allows productive and satisfying astronomy from home allowing one to do more astronomy. If the reader has any doubts on this, look at the explosive growth of CCD/CMOS imaging.

 

Pure visual DSO observers with conventional eyepieces are steadily becoming dinosaurs.

 

And if you are reading this to learn more about NV and shocked at the price - have you priced out a full CMOS imaging rig yet?


  • Bill Jensen likes this

#35 a__l

a__l

    Gemini

  • -----
  • Posts: 3,168
  • Joined: 24 Nov 2007

Posted 08 April 2021 - 06:51 PM

Night Vision is absolutely a techno-miracle.

 

I live in an extremely light polluted location just outside of Philadelphia with all types of light pollution; from strong local lights to the multiple light sources from a large city like Philadelphia to urban sprawl to one of the largest malls on the east coast just 3 miles away. That I can "easily" see the Horsehead Nebula and even spot the brighter sections of Barnard’s Loop is only possible through the “miracle” of image amplification provided by an image intensifier, without which these and many other objects would not be observable.

 

Bob

With the H-alfa installed, the glare from the flashlights penetrates any slot. For example, in the slot paracorr-2, when the head is extended. Doesn't help shroud telecope etc. Comparison of Barnard's loop with dark skies in my Fujinon (3x) or the loop or snippets(these are hard to see).
What is meant by "light polluted areas"?



#36 Dale Eason

Dale Eason

    Surveyor 1

  • *****
  • Posts: 1,988
  • Joined: 24 Nov 2009
  • Loc: Roseville,Mn.

Posted 08 April 2021 - 08:02 PM

What is meant by "light polluted areas"?

How can you ask that?  He already defined his location and the type of lighting very well in the first part of the message.  Here in the US being in or nearby a large city gives you close to the Bortle 8 or 9 zone or 7 at best.  For me I'm in a Bortle 8 zone SQM reading in the 18's and I get results similar to what he gets with the NV and I too call it a miracle.   It was something I never expected to see from my house.  For me with the HA 3.5 narrow band filter I even see Barnard's loop easily at 3X.

 

Dale



#37 a__l

a__l

    Gemini

  • -----
  • Posts: 3,168
  • Joined: 24 Nov 2007

Posted 08 April 2021 - 09:44 PM

One more question. I have read that night vision devices help you see even in light polluted areas. Does that apply even if the light pollution is coming from LED bulbs?

 

 

How can you ask that?  He already defined his location and the type of lighting very well in the first part of the message. 

Cincinnati? City center? Or how much from the center? Ohio? Where? I do not know this area and I am located many thousands of kilometers from it.


Edited by a__l, 08 April 2021 - 10:01 PM.


#38 Gschnettler

Gschnettler

    Messenger

  • -----
  • topic starter
  • Posts: 404
  • Joined: 14 Jul 2020
  • Loc: Cincinnati Ohio

Posted 08 April 2021 - 09:49 PM

I live pretty close to the city center. About 5 miles from downtown. Surrounded by houses and businesses in all directions. It’s really hard to find anywhere nearby that doesn’t have bright lights.

#39 a__l

a__l

    Gemini

  • -----
  • Posts: 3,168
  • Joined: 24 Nov 2007

Posted 08 April 2021 - 09:56 PM

I can only see part of the loop at the site in the center of my city (3x). When I look in my 18" I see almost nothing with the h-Alfa, only the glare from the flashlights. But I can see the planets well in my updated Zambuto (no NV).



#40 Dale Eason

Dale Eason

    Surveyor 1

  • *****
  • Posts: 1,988
  • Joined: 24 Nov 2009
  • Loc: Roseville,Mn.

Posted 09 April 2021 - 12:08 AM

Cincinnati? City center? Or how much from the center? Ohio? Where? I do not know this area and I am located many thousands of kilometers from it.

In the above conversation that you quoted (#35) he (bobhen) stated  "I live in an extremely light polluted location just outside of Philadelphia".

 

From the internet you can find his or anyone's approximate light pollution see  https://www.lightpollutionmap.info/

 

Dale


Edited by Dale Eason, 09 April 2021 - 12:11 AM.


#41 a__l

a__l

    Gemini

  • -----
  • Posts: 3,168
  • Joined: 24 Nov 2007

Posted 09 April 2021 - 12:57 AM

Here are cross references. I answered the OP's question. bobhen replied to my post. I continued the discussion in the sense of the OP's answer.

CN does not include cross-references, unlike other forums.

And I turned out to be right, since the OP is asking about the visibility actually inside the city.


Edited by a__l, 09 April 2021 - 01:01 AM.


#42 Dale Eason

Dale Eason

    Surveyor 1

  • *****
  • Posts: 1,988
  • Joined: 24 Nov 2009
  • Loc: Roseville,Mn.

Posted 09 April 2021 - 01:52 AM

So just in case it got lost in the confusion of a__i's posts.   Yes NV with the right filters will show you amazing things not thought possible in years past in the current light pollution typical of your location.


  • Jeff Morgan, bobhen and Gavster like this

#43 maxmir

maxmir

    Viking 1

  • ***--
  • Posts: 599
  • Joined: 03 Oct 2005

Posted 09 April 2021 - 08:49 AM

Dale,

 

You said that you built your own Mod-3C. Where did you buy the housing ?

 

Max



#44 bobhen

bobhen

    Fly Me to the Moon

  • *****
  • Posts: 5,388
  • Joined: 25 Jun 2005

Posted 09 April 2021 - 09:22 AM

What is meant by "light polluted areas"?

I live in a Bortle 8 zone. The only location worse would be observing from the actual center of Philadelphia. 

 

That I can see the N. American Nebula, the Monkey Head Nebula, the California Nebula, the dark gas nebulas that abound in Cygnus and Sagittarius and resolve small globular cluster that were previously just smudges along with many other previously unobservable objects is all due to Night Vision. Believe me I know, because I've lived and observed here for 35-years and with telescopes ranging from 3 to 15-inches.

 

Bob


  • 1E1HFPPE likes this

#45 Dale Eason

Dale Eason

    Surveyor 1

  • *****
  • Posts: 1,988
  • Joined: 24 Nov 2009
  • Loc: Roseville,Mn.

Posted 09 April 2021 - 10:40 AM

Dale,

 

You said that you built your own Mod-3C. Where did you buy the housing ?

 

Max

Sorry I did not say built my own but instead said assembled, meaning I bought the Mod3c and all adapters instead of buying a complete Tele Vue solution.



#46 Gschnettler

Gschnettler

    Messenger

  • -----
  • topic starter
  • Posts: 404
  • Joined: 14 Jul 2020
  • Loc: Cincinnati Ohio

Posted 26 April 2021 - 06:53 PM

Hi again. So I have my PVS-7 but I’m not sure what to do next. Do you think I should:

A) get a c-mount adapter and a 1.25” adapter and put it in a telescope?

B) get a 1.2” to 1.25” adapter and an NV filter?

C) get some adapters so that I can connect it to a variety of Nikon lenses?

Note that I live in the city...Bortle 7 or 8...tons of light pollution.

I assume that I want to eventually do A,B and C. But I’d like to take it one step at a time and enjoy the gradual buildup in capabilities.

#47 Dale Eason

Dale Eason

    Surveyor 1

  • *****
  • Posts: 1,988
  • Joined: 24 Nov 2009
  • Loc: Roseville,Mn.

Posted 26 April 2021 - 07:56 PM

In heavy light pollution you need filters for each configuration.   So start with either a HA narrow band of 6nm or so to see emission nebulae.  A long IR pass like a 685 filter to see star clusters and galaxies but those require more power so a telescope is handy but not just any telescope.   One that is fast enough to use with the filtering loss of light.

 

Then if you already have Nikon lenses get the adapters you need to attach those lenses and adapters to attach the filters to the lenses.   So that means 2 inch filters.

 

However you are going to want to use a telescope as well.   So just do what is necessary to get all configurations working.   Pick one if you have to but just do it.   You will be glad you did I'm sure.

 

In light pollution an NV without filters is an interesting toy.   With filters it becomes an amazing journey of new discoveries.

 

Dale


  • 1E1HFPPE likes this

#48 Mazerski

Mazerski

    Viking 1

  • *****
  • Posts: 638
  • Joined: 13 Nov 2013

Posted 26 April 2021 - 10:56 PM

Based on your Qs:

 

A) Yes, get the c-mount nosepiece and a ScopeStuff C-mount to 1.25" adapter and a 1.25" Baader 685nm IR and Astronomik 6nm CCD Ha filter. Then you can use in your scope. Photo #1.

 

B) If you get the ring adapter, screw in the IR or Ha filter and you get 1x. That's it. Others may have instructed you if you keep the "stock" nosepiece / objective, you can use afocal with adapter(s).

 

C) Adapters for lens = yes. I do this but use 1.25" filters. Nikon F to C adapter with Nikon non-Ai lens. Photo #2 and #3.

Attached Thumbnails

  • Capture.JPG
  • NV_11.JPG
  • PVS7.JPG


#49 Gschnettler

Gschnettler

    Messenger

  • -----
  • topic starter
  • Posts: 404
  • Joined: 14 Jul 2020
  • Loc: Cincinnati Ohio

Posted 27 April 2021 - 08:46 AM

Thanks for all of the info. I think I’m pretty close to understanding it. One more thing though...what do the numbers mean for the filters?

Does 685nm mean that it shows light 685nm and lower?

What does a 7nm filter mean then? Certainly it’s not for light waves 7nm and below. Ha is at 656nm. Does the 7nm mean +/- 3.5nm from 656?

Edited by Gschnettler, 27 April 2021 - 08:46 AM.


#50 maxmir

maxmir

    Viking 1

  • ***--
  • Posts: 599
  • Joined: 03 Oct 2005

Posted 27 April 2021 - 01:58 PM

Thanks for all of the info. I think I’m pretty close to understanding it. One more thing though...what do the numbers mean for the filters?

Does 685nm mean that it shows light 685nm and lower?

What does a 7nm filter mean then? Certainly it’s not for light waves 7nm and below. Ha is at 656nm. Does the 7nm mean +/- 3.5nm from 656?

Does 685nm mean that it shows light 685nm and lower?  : Yes these are called low pass filters.

 

Does the 7nm mean +/- 3.5nm from 656?  : That's right these are narrow bandwidth filters around the spectral line. 7nm is the bandwidth.


  • 1E1HFPPE likes this


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics