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Future NV Setup...

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#76 BJS

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Posted 21 May 2019 - 01:47 PM

Stargazer:

What about ebi,halo, etc?

#77 Vondragonnoggin

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Posted 21 May 2019 - 01:55 PM

Stargazer:

What about ebi,halo, etc?

Minimum specs for Omni VII:

 

Resolution - 64 lp/mm

S/N - 28

Photocathode Sensitivity - 2200

Halo - .7

EBI - 3

Gain - 50,000 - 80,000

 

If a Tube is untested but Omni VII contract, it will have at least these minimums.


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#78 havasman

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Posted 28 May 2019 - 05:07 PM

Funds are dispatched and I expect to have the system John has put together in this forum string, which I have followed closely since inception, in-hand in a couple of weeks. grin.gif

 

Several factors work together to make NV a good option for me just now. What has held me back has been resolved by the fine system integration work you experts have done via this forum string. So I add my sincere thanks for your work to John's. System integration has been lacking for NV and the resulting confusion seems to me to keep lots of folks from jumping in; certainly did for me. I expect early confusion with the start-up and you'll likely get to field some Q's from me if you will. But the completeness of the package and proven capability may minimize even my confusion.

 

Here we go!


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#79 Doug Culbertson

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Posted 28 May 2019 - 06:14 PM

Welcome aboard, Dick! Be prepared to be gobsmacked. FWIW, you’ll be wanting to do some prime focus observing with the Mod-3 and Ha filter in that Starmaster. Mine easily reaches focus with my Mod-3c and Antares .7x reducer. 


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#80 havasman

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Posted 10 June 2019 - 01:19 PM

I was unable to get an image via the GSO mirror diagonal and, with A-T extenders got the proof of concept success by going straight through - A.K.A. the neck breaker.

 

But I found the APM prism diagonal has enough shorter light path to allow the system to work well, with maybe 5 or 6mm of travel left. Nothing allows the 0.5 FR in the mix. So it's likely going to see a new focuser.



#81 Vondragonnoggin

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Posted 10 June 2019 - 02:53 PM

I was unable to get an image via the GSO mirror diagonal and, with A-T extenders got the proof of concept success by going straight through - A.K.A. the neck breaker.

 

But I found the APM prism diagonal has enough shorter light path to allow the system to work well, with maybe 5 or 6mm of travel left. Nothing allows the 0.5 FR in the mix. So it's likely going to see a new focuser.

I use a GSO linear bearing with 120ST stock collar on mine. It’s the 96mm version that fits stock collar. They also have a low profile adapter and 86mm version to fit adapter at ScopeStuff, but shortens scope length quite a bit and would require extensions to use with a diagonal. The stock collar/GSO focuser is just like regular eyepiece use. No configuration besides straight through would allow for .5x focal reducer use where the FR normally goes. The .5x reducer screws on the nosepiece of my NVD and then put in diagonal like regular eyepiece. You can put a filter on the reducer also or screw the filter on the diagonal. It’s not a full .5x reduction. On the nosepiece it gives me .7x actual reduction.

 

With 2” reducer and 2” short nosepiece I have about 2mm to spare on infinity focus before bottoming out.


Edited by Vondragonnoggin, 10 June 2019 - 02:57 PM.


#82 havasman

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Posted 29 June 2019 - 03:44 PM

I got out about midnight last night for a first GOOD session with this NV kit. The Milky Way passed meridian during the session and except for the lack of darkness conditions were OK, still and clear with mosquitoes making the only clouds until @ 3am. I used the 6nm Ha filter w/o reducer as I still have the stock focuser and APM prism diagonal that enabled focus. I'm working with Jim at Scopestuff to get the right focuser in place to use a reducer later. Over a 3 hour period observations from my very light polluted white zone driveway site included:

  • M8 - chosen 1st for familiarity and bright stars to achieve focus it showed very good extension and brightness, little interior detail, overall quite large in field
  • M20 - sm, brt main body, dark lanes in center, faint extensions NE
  • M16 - ~lg, brt, outline shape ~clear, little interior detail
  • NGC7000 - huge! ~brt, mostly amorphous
  • NGC6888 - crisp and bright outline only, thin shell for almost the entire egg shaped outline, clear and pretty
  • M27 - ~brt, apple core shape apparent
  • M57 - sm, V brt thin ring with quite a bit of shimmer

But then it got really good and I started to see what it is folks rave about. I went to the Sadr area to see what I could see. These were pretty cool.

  • IC1311 - never saw this before with any of my gear, elongated flared ~brt nebulosity, apparent in the field
  • IC1318 - never saw this either except in other's pics, several large patches of apparent nebulosity, ~brt & apparent

Also saw the brightest part of IC4592 nearest the star. 

 

Next night with any chance for observing is forecast for next Tuesday and I want to work out what the size of the field I'm seeing is and give the bandpass filter a look too. But this was a good session.



#83 Mazerski

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Posted 29 June 2019 - 04:28 PM

Good to hear of your success. You mention M8, 20 and 16 but neglected to mention the best one - M17 (near the Eagle).

Did you fail to write it down or not aware of it? It’s big and bright.

 

Do you have an 685 or 642IR? You need to check out M22, 28, 4, 80... lots of globs visible now.


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#84 Jeff Morgan

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Posted 30 June 2019 - 01:53 AM

Next night with any chance for observing is forecast for next Tuesday and I want to work out what the size of the field I'm seeing is and give the bandpass filter a look too. But this was a good session.

 

Congrats on a good session!

 

IMHO, for the NV astronomer Cygnus suddenly vaults to the best constellation in the sky - despite it's lack of globular clusters. Come to think of it, the open clusters there aren't even that great. But the nebula ... wow! More square arc minutes of bright (really bright) nebula than any two (or three) other constellations in the sky combined.


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#85 havasman

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Posted 30 June 2019 - 03:13 AM

Good to hear of your success. You mention M8, 20 and 16 but neglected to mention the best one - M17 (near the Eagle).

Did you fail to write it down or not aware of it? It’s big and bright.

 

Do you have an 685 or 642IR? You need to check out M22, 28, 4, 80... lots of globs visible now.

Nah, I just skipped over it in making the post from my notes. And best is kinda arbitrary. The best last night were the ones I'd never seen before with any of my gear as they showed me some of the potential of the NV system.

 

M17 was bright overall with the main body very bright and good extension showed below and behind the "swan" feature with a separated nebulosity out in front of the big bird. Some, but not much, internal detail was visible particularly in the extensions.

 

The big bright nebulae are uniformly better to my eye from a dark site with the 16" or 10" and an appropriate narrowband filter and eyepiece.

 

The passband filter is a 642 and when I used it to see M4 it was pretty good. I was able to make out hints of the N-S bar of stars running through it but not to resolve individual stars on the core or extended halo as points at all. But I'm just getting the hang of this electronic thing.



#86 Eddgie

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Posted 30 June 2019 - 07:17 AM

Good report.

 

 

 

The big bright nebulae are uniformly better to my eye from a dark site with the 16" or 10" and an appropriate narrowband filter and eyepiece.

 

 

Well, remember, you are in a white zone. While your band pass filter does reduce the amount of off band light, it does not eliminate it.  Typical leak is 2% to 4% and while that does not sound like a lot, you have to consider that it is 2% to 4% of all of the light out if band from about 500nm to 875nm.  While at no single point along the spectrum do you get more than 2% or 3%, but the total amount of background glow is considerable. 

 

Also, probably a lot of absorption where you live.   Even in Austin, on a hot, muggy day, transparency plunges.   Did you shoot an SQM reading?   

 

Also, on a hot night, the EBI will be high though I know it got to 70 last night in Austin (rained) so maybe you had cooler than this.

 

What can you expect from a dark sky?   I am going to link picture and from a dark sky, I can tell you that I have seen pretty much all of this nebula.  To be fair, it will be much dimmer than shown here, but if you find M29 in this picture, you see that it sit on a small puff of nebula and I have seen that pretty easily.  

https://apod.nasa.go...d/ap170322.html

 

Here is chart with feature names.

 

https://www.google.c...5mfdQnyE_De6lM:

 

So, while NV is pretty good in the city, under dark skies on a cooler night, the amount of nebula you can see is considerably higher (I still think it is staggeringly good from a Bortle 2 sky..  Just incredible).

 

That is why from time to time I urge people on this forum to still get out to dark, clear skies.  Just as with conventional telescopes, there is no substitute for dark skies. Many of these items will appear almost photographic.

 

At the least though, you can now see these objects form the city!

 

(Here is an image of the Lagoon and Trifid.  Most of the nebula in this picture will show in dark skies, but in bright skies, even with heavy filter, you only see the Lagoon and Trifid.  Under dark skies (and even under city skies on a good night with a fast telescope) you can see the extension coming from Lagoon and going to the left in this picture.  At the left of this extension, it is actually a different nebula, and under darker skies, there will be an unbroken bridge connecting them together as shown in the picture.)

 

Happy you are getting some NV time.   Been cloudy as heck 200 mi to the south of you.



#87 havasman

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Posted 30 June 2019 - 01:45 PM

Good report.

 

Well, remember, you are in a white zone. 

Happy you are getting some NV time.   Been cloudy as heck 200 mi to the south of you.

Oh yes, absolutely. The city light dome and local light sources ARE the problem. I had hoped for the technology to present a cure-all for the conditions and it does show bright, extended nebulae very much better than they can be seen from here w/o it. And, from this really poor site, the NV system showed the very faint Cygnus nebula clouds to me for the first time. That was very impressive. The highest SQM-L reading I've taken from here is 17.8. There is NO Milky Way and severely limited star visibility.

 

I have friends in Circle C and hope to get down there for an NV session. Controlled lighting there is very effective. I have observed from their back yard and it's a lot better than from my back yard. I had the NV system at Marble Falls last weekend but all we did was watch deer graze along the lake behind the house as it was fully cloudy.

 

I believe you and agree that dark sky conditions will likely transform these NV observations as they do other observing. I hope to get a dark sky session with the system.



#88 Eddgie

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Posted 30 June 2019 - 05:12 PM

Oh yes, absolutely. The city light dome and local light sources ARE the problem. I had hoped for the technology to present a cure-all for the conditions and it does show bright, extended nebulae very much better than they can be seen from here w/o it. And, from this really poor site, the NV system showed the very faint Cygnus nebula clouds to me for the first time. That was very impressive. The highest SQM-L reading I've taken from here is 17.8. There is NO Milky Way and severely limited star visibility.

 

I have friends in Circle C and hope to get down there for an NV session. Controlled lighting there is very effective. I have observed from their back yard and it's a lot better than from my back yard. I had the NV system at Marble Falls last weekend but all we did was watch deer graze along the lake behind the house as it was fully cloudy.

 

I believe you and agree that dark sky conditions will likely transform these NV observations as they do other observing. I hope to get a dark sky session with the system.

Circle C/Mansfield Dam is not as good as it used to be, but it is a heck of a lot better than a white zone.  

 

My guess is that with a 680nm filter, you will be able to see the Milky Way from your home.  I live in a red zone (orange to white depending on the night) and most nights, I can easily see the Milky Way but once again, while it is as good as naked eye under Bortle 4 skies, seeing the Milky Way using NV from a dark sky is a titanic experience. 

 

I don't think anyone on the forum would suggest that NV will always show you more than you would be able to see with conventional gear under dark skies, but from the city, it can still greatly expand what can be seen.  I mean I can see the Pillars of Creation from my back yard using a 12" dob.  I had never seen them before using anything from anywhere I have ever observed from (though to be fair, I used to rarely get to Bortle 2 skies).

 

If you can get out to Enchanted Rock, it is pretty epic.   Bortle 2, and even naked eye Milky Way is pretty spectacular, but with NV, it is going to be like being in a spaceship. 

 

If you go to Mansfield, let me know and I will try to meet you out there. 


Edited by Eddgie, 30 June 2019 - 05:13 PM.


#89 cnoct

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Posted 01 July 2019 - 05:37 AM

Should anyone in the DFW area want instrument validation of their Isystem, Ident Marking Services over in Rockwall can do just that. They employ equipment and a few persons from the now closed L3 NV plant in Garland, an incredible resource for those in N Texas. Not sure if they still do demo nights but if they do it's great opportunity to check out the latest NV technology or just to see ones preference for green or white phosphor.


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#90 pwang99

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Posted 01 July 2019 - 09:42 AM

Please let me know if you're going to Mansfield. Also, there is a spot I observe from out in Manor that is typically darker than Mansfield.

Also, I've just had 3 GLORIOUS nights of observing in July: Ft. Davis with my 16", and two nights in Bortle 1 in Jackson Hole, WY with my new 10" f/3 (including focal reduction to f/1.9).

I'm going to be writing up the observing reports on the flight back to Austin today. But, I definitely have more to report about NV (broadband and H-a narrowband) vs naked eye, under dark skies, and the merits of aperture and speed.

Edited by pwang99, 01 July 2019 - 12:24 PM.

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#91 Eddgie

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Posted 01 July 2019 - 01:23 PM

Peter, looking forward to your report!   Happy to hear that you got your 10" f/3 mirror.  



#92 Jeff Morgan

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Posted 03 July 2019 - 03:20 PM

Please let me know if you're going to Mansfield. Also, there is a spot I observe from out in Manor that is typically darker than Mansfield.

Also, I've just had 3 GLORIOUS nights of observing in July: Ft. Davis with my 16", and two nights in Bortle 1 in Jackson Hole, WY with my new 10" f/3 (including focal reduction to f/1.9).

I'm going to be writing up the observing reports on the flight back to Austin today. But, I definitely have more to report about NV (broadband and H-a narrowband) vs naked eye, under dark skies, and the merits of aperture and speed.

Awesome!

 

Look forward to hearing about those comparisons.



#93 havasman

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Posted 03 July 2019 - 08:41 PM

Ordered 2-spd, 2" GSO Linear brg focuser that if everything matches the published dimensions and my measurements are good should gain 1.14" shorter light path! That should go a long way toward fixing the mechanical issues.  smile.gif


Edited by havasman, 03 July 2019 - 11:27 PM.


#94 havasman

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Posted 10 July 2019 - 12:05 PM

Well, here's one last report on this project that has now made its goal of creating a working NV system. The GSO linear bearing Crayford focuser (96.6mm flange) from Agena was the last key piece. There is now > 1cm of free travel past focus with 0.7 reducer and Scopestuff diagonal and system function is free of mechanical constraints.

jump.gif

 

I was not about to attack the integration problem on my own and thank all of you sincerely for your good work putting the package together!

 

With the reducer and 6nm filter in place the Sadr region last night pretty much exploded with nebulosity all around, bright, easily seen interconnected nebulosity. Previously limited to using no reducer due to focus travel issues there had only been medium sized patches visible. Other results in different areas were similar. And this is from the Dallas white zone.

 

Thanks again everyone.


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#95 Eddgie

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Posted 10 July 2019 - 02:27 PM

Happy to hear that it is coming together. 

 

There is more than nebula out there, so don't forget to use you bigger scopes.  NV in the city is not really going to be much better than glass from a dark sky, but the point is that you don't have to go to a dark sky to get some decent DSO observing.

 

That being said, when you do get to a dark sky, hold on to your hat...



#96 Vondragonnoggin

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Posted 10 July 2019 - 04:09 PM

NV in the city is not really going to be much better than glass from a dark sky

I would highly disagree with this statement. I’ve seen much more nebulae in red/white zone with 72mm than I ever saw in blue zone with 152mm glass.

 

I’ve never been to black or grey zones so can’t say there, but can’t imagine regular glass in any zone matching my 150mm at F/1.4

 

I’ll definitely agree about NV showing more from darker skies. That same blue zone with NV in my 152mm was pretty amazing. I was at F/4 with the 152mm. If I was to go to the same zone today I would definitely shoot for a faster optic while balancing some image scale. Maybe settle on F/2.8 with 152mm in a blue zone or darker to make the trip worthwhile.


Edited by Vondragonnoggin, 10 July 2019 - 04:28 PM.


#97 Vondragonnoggin

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Posted 10 July 2019 - 04:16 PM

To Havasman - that must be the length difference of the standard GSO vs the linear bearing or the difference between the NVD Micro and Mod 3. I have 2mm left on stock collar with .5x reducer on 96mm linear bearing.

 

That said - the 120ST with .5x reducer on the nosepiece is giving me an actual .7x reduction. The difference at F/1.7 with an afocal setup vs F/3.5 at prime is again drastic. Like going from native F/5 to F/3.5 difference.

 

You lose image scale fairly good (I was at 7.7x) but all kinds of interesting things started becoming visible where they previously weren’t at F/3.5.

 

Something to think about in the future maybe. Considerably less scintillation on my fixed gain device as well. Matched the smoothness on view to turning down gain a hair on my manual gain device.


Edited by Vondragonnoggin, 10 July 2019 - 04:19 PM.

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#98 Eddgie

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Posted 11 July 2019 - 06:30 AM

I would highly disagree with this statement. I’ve seen much more nebulae in red/white zone with 72mm than I ever saw in blue zone with 152mm glass.

 

I’ve never been to black or grey zones so can’t say there, but can’t imagine regular glass in any zone matching my 150mm at F/1.4

 

I’ll definitely agree about NV showing more from darker skies. That same blue zone with NV in my 152mm was pretty amazing. I was at F/4 with the 152mm. If I was to go to the same zone today I would definitely shoot for a faster optic while balancing some image scale. Maybe settle on F/2.8 with 152mm in a blue zone or darker to make the trip worthwhile.

Ok, yes, I overstated.  Nebula is pretty much always better even from the city..  I was thinking more of DSOs where people often report having seen this or the DSO better from dark skies using conventional eyepieces than they do from the city using NV.  Havasman himself gave an example of this.

 

The 6" f/2.8 is pretty glorious under dark skies.  I have seen fields with star counts in the many thousands.  The first time I saw the Ink Spot nebula and the incredibly dense surrounding star field with the 6" f/2.8, I just about fell out of my chair.  The nebula was so pitch black against the ultra-rich background that I thought I was looking at an old Mount Polamar Hale telescope black and white image of it. While we tend to dote on H-a nebula, dark nebula is also I think far better in NV than with naked eye and the Ink Spot is one of the finest due to the density of the surrounding star field.


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#99 moshen

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Posted 17 July 2019 - 02:40 AM

Please let me know if you're going to Mansfield. Also, there is a spot I observe from out in Manor that is typically darker than Mansfield.

Also, I've just had 3 GLORIOUS nights of observing in July: Ft. Davis with my 16", and two nights in Bortle 1 in Jackson Hole, WY with my new 10" f/3 (including focal reduction to f/1.9).

I'm going to be writing up the observing reports on the flight back to Austin today. But, I definitely have more to report about NV (broadband and H-a narrowband) vs naked eye, under dark skies, and the merits of aperture and speed.

 

Peter do you have photos of your 10" f/3? Would love to see how it turned out and still looking forward to hearing your report too!


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#100 PEterW

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Posted 17 July 2019 - 03:16 PM

Yes, I missed the post where that appeared!! What focusser/eyepiece combo are you finish work best?
How does it compare to other stalwarts? Do you use it with boring old glass eyepieces??

Peter


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