Galaxies, Cygnus and Sagittarius (night vision)

[Saganite]

On 05/05/2019 at 09:28, tooth_dr said:

Wow! What a session. 

What Adam said with bells on !!

Particularly loved M51.

Edited May 9, 2019 by Saganite

[Stu]

3 hours ago, RobertI said:

One question, why is it that NV does not help on reflection nebs, I would have thought it should work on any faint object?

A couple of reasons that I can think of. Firstly NV response is better at the red end of the spectrum so it tends not to pick up the blue reflection nebulae.

Second point it's that NV works at it's best when filtering heavily on Ha frequencies. It has good response in these frequencies, but also the filtering removes most/all of the unwanted light (LP) before amplification, then amplifies the light from the target. This greatly enhances the contrast and makes these virtually invisible plainly visible.

[RobertI]

1 hour ago, Stu said:

A couple of reasons that I can think of. Firstly NV response is better at the red end of the spectrum so it tends not to pick up the blue reflection nebulae.

Second point it's that NV works at it's best when filtering heavily on Ha frequencies. It has good response in these frequencies, but also the filtering removes most/all of the unwanted light (LP) before amplification, then amplifies the light from the target. This greatly enhances the contrast and makes these virtually invisible plainly visible.

Thanks Stu. So is NV worse for reflection nebulae than for say galaxies and globs? I am guessing that galaxies and globs are significantly redder than reflection nebs so  would look better?

[DirkSteele]

I need to stop reading these posts Gavin!  I am going to end up buying one of these NVs.  And I have a C11.....

[GavStar]

1 hour ago, DirkSteele said:

I need to stop reading these posts Gavin!  I am going to end up buying one of these NVs.  And I have a C11.....

Well Matthew, I won’t be making any more posts since I’m now not allowed to post my reports in the visual observing sections (which is where I’ve been posting them for the last 18 months and where I originally posted this report).

But I hope you do try night vision. It was fun when we had a go at Regent’s Park a few months back and great from my London back garden but it’s truly amazing from dark (sqm 21+) sites....

Edited May 9, 2019 by GavStar

[Highburymark]

6 hours ago, RobertI said:

Just read the Astronomy Now article, and a cracking read it is too, and a very clear summary of how NV works. 

One question, why is it that NV does not help on reflection nebs, I would have thought it should work on any faint object?

One thing that was interesting from the article, was that if the  cost of the NV tube wasnt enough, it seems that even eyepieces need to be premium (due to limited number of manufacturers offering the right connectors), then the focusser has to be premium to hold all that weight safely, and presumably the tripod, mount and saddle need to be very solid to stop all that equipment crashing to the ground. As with imaging, it was probably a financially painful learning experience for you both!? Thanks for going through that pain for us! Ironically it seems that the scope doesn't need to be premium for best NV results, kind of the opposte of imaging, and also visual to an extent?

Anyway thanks again for a great article.

Thanks Rob - glad you liked the article. You're absolutely right about the added expense - filters (check the price of a 5nm ha Astrodon or Chroma), TeleVue eyepieces etc. But it needn't cost a fortune - can use Baader filters and Hyperion eyepieces too (and TV plossls), not just Panoptics. Basically any EP that takes dioptrx. Also NV works really well with small scopes too so don't need a heavy mount. Decent focuser is important to carry the monocular and eyepiece though. And go-to is helpful too - SW AZGTi works well as simple alt az set up with a camera tripod.

Edited May 9, 2019 by Highburymark

[RobertI]

1 hour ago, GavStar said:

Well Matthew, I won’t be making any more posts since I’m now not allowed to post my reports in the visual observing sections

I probably haven’t kept up with recent events, but I thought it was deemed ok by the mods? 

[GavStar]

6 minutes ago, RobertI said:

I probably haven’t kept up with recent events, but I thought it was deemed ok by the mods? 

I thought so too Robert, hence I posted this report in the visual deep sky observing section. However after a day it was moved by a mod to the EEVA section and I was informed by pm not to post in the visual observing sections from now on.

[Stu]

4 hours ago, RobertI said:

Thanks Stu. So is NV worse for reflection nebulae than for say galaxies and globs? I am guessing that galaxies and globs are significantly redder than reflection nebs so  would look better?

Well I think reflection nebulae tend towards the blue end so are not picked up so well. Galaxies are generally broadband and can have Ha regions in them so tend to be better than reflection nebs. Globs do show a good improvement over the view without NV although I probably prefer the stars as viewed without from a purist perspective.

[Littleguy80]

2 hours ago, GavStar said:

I thought so too Robert, hence I posted this report in the visual deep sky observing section. However after a day it was moved by a mod to the EEVA section and I was informed by pm not to post in the visual observing sections from now on.

Excellent report and images, Gavin. I do hope you reconsider. The visibility of NV in SGL will all but disappear if you don’t post any more reports. Why not post a few reports in the EEVA section and see how the numbers compare? That will very quickly show whether the visibility of your reports has dropped or not. It’s a different conversation when you can demonstrate the impact of a decision. Who knows, you may even find there’s little or no effect. 

[R26 oldtimer]

Excellent report GavStar. And one I wouldn't have noticed if burried in the visual observation section. Again congrats and keep up posting!

 

[PeterW]

The human eye has actually greater quantum efficiency than the intensifier (IIRC), but the intensifier has a much wider bandwidth of colours it is sensitive, so you see more. It’s essentially blue blind, the photonis is supposed to be better in this regard, but the judges are still out about reflection detection as some reflection nebulae have a bit of emission in confusing things. There are second hand systems out there that can show much of this stuff... not as well as our illustrious new NV innovators, but plenty cheaper. Gain control is the one thing the new systems have that’s very desirable. As long as you avoid the gen1&2 which don’t offer enough benefit to be worth really using. More spec is more better of course. Many people express an expectation of price drops, but I wouldn’t put money on that happening unless the US dropped its export restrictions and the US manufacturers went nuts expanding their markets. Also the expectation of performance improvements, again there has been very gradual improvements but nothing huge (some mil specs have actually been lessened), like camera sensors we are probably near as good as we’ll see. For those wanting to find stuff in the dark the longer spectral windows of thermal are the place be, rapid spec improvements and price drops.

Peter

 

[Fraunhoffer]

impressive.
Which NV was this?
(sorry if I missed that scanning through the post)

 

[PeterW]

Gavs is either a Photonis Intens or a Harder Gen3, both white phosphor, both high res and with gain control. The harder appears to be a wee bit better on nebulae, but both do a fantastic job.

Peter