GavStar

One of the key benefits of night vision astronomy is the ability to observe many DSOs from a light polluted site which would otherwise be invisible (or virtually invisible ) with normal glass eyepieces.

However, light pollution still has quite an adverse impact on the views with night vision compared to observing from a dark site. I was pretty impressed with the nebulae views I got from London earlier this week. But I still get significantly more enjoyment from night vision when observing at a dark site. 

In June this year, I observed several of the same nebulae from a dark site on the Isle of Wight (sqm 21+) using a reasonably similar setup (effective speed, aperture, image scale).

I attach the London vs Isle of Wight night vision comparison of the North America, Butterfly, Veil, Pac-man, Soul nebulae. Quite a difference I think!!!

1 hour ago, Stu said:

It’s funny, I had a chat on messenger last night with @GavStar about the fact that I said that I’ve never seen the Horsehead nebula in a recent post.

Of course I HAVE seen the Horsehead a few times through Gavin’s NV gear and it is amazing to see. I guess though that there is a ‘rite of passage’ which is about having the right kit, location, conditions and skill to see these targets visually because it is tough even with an Hb filter. With NV it is just ‘there’, so I did also say to Gavin that NV was cheating 🤣🤣, but despite this being a dagger to his NV heart I hope we are still friends 😆😉🤣.

 

Nope you’re off the Christmas card list now @Stu 🤣🤣

18 minutes ago, Stu said:

You made the most of the clear night Gavin 👍. The forecast was wrong here so I wasn’t expecting it to be clear.

A very capable setup despite being so ‘grab and go’, although amazing to see the different image scale between this and your C11 and 16”.

Thanks Stu. As you know I was going purchase a Sharpstar 13028 as a larger aperture grab and go. But after last night I think I’m going to stick with the easy setup, pinpoint stars and lovely flat field of the fsq85 (night vision is notorious for exaggerating any fc exhibited by the scope).

And you’re right, the fsq85 and c11/16 inch dob work in great partnership for big and small objects respectively…

It was a lovely clear night sky in London tonight and also no moon so I thought it was about time for a decent night vision astronomy session.

I went for my grab and go setup, ie az gti mount and Takahashi fsq85. First up was a bit of experimenting with my Televue 67mm and reducers and also my Televue 55mm in afocal mode with my pvs-14. Given the light pollution I only used my chroma 3nm ha filter. The reducers gave relatively disappointing star shapes tonight so I quickly just focussed on the eyepieces only. The 67mm is nice with good stars to the edge but it does suffer from some vignetting - not really noticeable for visual but quite obvious when I take some phone pics through it. The 55mm didn’t have the vignetting but the edge stars were pretty yucky (lines not points!).

I then dusted off my Televue panoptic 41mm to compare with my experiences with the 67mm and 55mm. Although a bit dimmer, the 41mm didn’t vignette and also had nice sharp round stars right to the edge. As a result it stayed in the focuser for the rest of the session. I started with Cygnus (North America, Veil and Butterfly) and then gradually made my way across the rest of the sky taking in the Pac-man, Heart, Soul, California, Monkeyhead, Rosette and then finally the Flame/Horsehead. Phone pics attached and bearing in mind this is from an sqm 18 (light polluted) London back garden, I really want to get this setup to a dark site soon. The fov of around 4 degrees frames many showpiece nebulae very nicely.

I think November is one of the best times to observe with night vision - there are loads of showpiece nebulae all over the sky - and nebulae are what night vision really excels at. I’d definitely recommend grabbing your nv kit and scope at the next clear night to do a “Grand nebulae tour”.

2 hours ago, joko said:

What do you mean by "something else is making a bigger difference…" Because there is something else you do not explain, the PVS-14 is just the housing, you have an OVNI Night Vision Astronomy grade tube designed for astronomy in your PVS-14.

And knowing you have an OVNI Night Vision Astronomy grade intensifier tube in your best PVS-14 housing, tube that i supplied to you, it means you have the same tube performance in your OVNI-M. And there are absolutely no other parts between the tubes and the SLR/Camera lens. So the only difference is this SLR/camera lens. Nothing else can explain the difference you get.

As you explain, there are a lot of positive comments on CN, (i never read any negative) so there are obviously something that makes the difference. For sure, it is the lens.

I already tried a lens at f/2 and the view was really bad, close from your Fujinon f/1.8. And it was incomparably better with the Cosmicar f/1.4 (close to your f/1.5 lens). Like most OVNI users have.

So the difference is due to the lens and nothing else.

 

What I mean is that the difference in f ratio between the lens of f1.5 and f1.8 is not the key reason for the major differences I am seeing when observing nebulae. C mount lens like the fujinon and cosmicar are not designed for use with an nv monocular - it’s just that they have a c mount thread and so can be attached straightforwardly. The afocal 3x lens is specifically designed for use with a pvs14 - I think this a key reason why I am getting better results with it (using either my actinblack pvs14 or my Carson/ovni pvs14) than than ovni with fujinon lens.

1 hour ago, joko said:

I would like to clarify one very important point that was not explained in the review. The PVS-14 is just the "housing". The intensifier tube in the PVS-14 is an OVNI Night Vision "Astronomy grade" tube specially designed for astronomy. 

Around 80% of the price of a Night Vision Device is dependant of the tube.

There is some confusion here. To confirm I have two pvs-14 monoculars. One is a complete setup (ie pvs-14 body and harder nv tube) purchased from actinblack, the other is one I built using a harder tube purchased from ovni and a pvs14 Carson milspec body/lens kit purchased from nighttec in Germany. 

The astronomy now review comparison was done before I received the Carson pvs14 kit and so the comparison was done between the actinblack pvs14 and the ovni-m.

The full review is now available online here

https://astronomynow.com/2021/07/29/reviewed-ovni-m-fom-2600-night-vision-eyepiece/

1 hour ago, joko said:

Fujinon is f1.8 while most OVNI-M users have Cosmicar 75mm f/1.4 and emission nebulae are amazing with h-alpha filter.

I never heard any negative feedback with the Cosmicar lens. All feedbacks are positive like those you read on CN.

Only about half an f stop difference between the Fujinon and the Cosmicar so wouldn’t be much of an impact. The 3x afocal lens is f1.5 and the difference I observed visually on emission nebulae with ha filter between the fujinon and afocal lens was more like 3-4 f stops rather than half, something else is making a bigger difference…

Good catch! I must try out m57 with some decent aperture and scale sometime!!

3 hours ago, stnagy said:

Interesting. I haven't tried the specialist 3x afocal lens. It sounds like it is worth a try. Do you mind me asking where did you get yours? How do you use it with a filter? 

Since I’m based in the UK I got from actinblack in Luxembourg. However if you are in the USA they are more freely available and there are multiple versions some of which are better then others.

I used this adapter to put the 1.25 filter between the pvs14 and 3x afocal lens. There is material vignetting due to the adapter etc but the centre 70 percent or so is excellent…

https://rafcamera.com/adapter-envis-3x-to-pvs-14?amp=1

3 hours ago, vineyard said:

That's a great idea @Martin Meredith - many parts of the world with rolling powercuts get that already & civilisation doesn't collapse.

Its dangerously addictive b/c now I'm imagining what a headset with binocular NV in a proper dark sky zone would be like!😂 

Binocular nv is very cool - I think the jump up from mono to bino nv is noticeably bigger than the jump from mono to bino with normal glass. Bino is definitely my preferred way of nv observing but quite tricky to get aperture with this so I stay at 1x with the monoculars or 10x with the big binoculars as per these threads. It does start to get a but expensive though…

48 minutes ago, stnagy said:

Is it the computar f2.8 lens? If so, it's gathering about 1/4 the light intensity of a specialist 3x afocal lens (at f1.5), which might be why you're getting those results. 

It’s the 75mm f1.8 fujinon c mount, so a bit slower than the f1.5 but not much. The difference was pretty embarrassing for the fujinon though…

@vineyard

1) Excellent re the tinkering. I think it’s very worthwhile since I read stuff like the 6-12 nm ha filters being best but after trying a 12,7,6,5 and 3nm filter it’s clear that for me the 3 is the best to bring out the most nebulosity with nv. So definitely keep on experimenting to work out what it best for your personal preferences.

2) here’s a cn link that may help you?

https://www.cloudynights.com/topic/730773-why-doesnt-a-camera-lens-work-a-focally/

3) Finally, (and probably least important), I’ve been able to try a camera lens and 75mm c mount lens in prime mode with my ovni-m. Both approaches disappointed me particularly on emission nebulae where with an ha filter both lens really struggle to show the nebulosity compared with my specialist 3x afocal nv lens. So I’ve stopped messing around with the camera lens as I’m happy with my afocal 3x lens setup. It perplexes me quite a bit about the positive comments made on cn re using camera lens/c mount lens with ha filters and nv as I just couldn’t get them to work at all well…

6 hours ago, Stu said:

The reducer/flattener takes it to f4.8, presumably getting rid of the curvature too.

The reducer/flattener requires 55mm spacing to the focal plane which means it can’t be used for visual purposes with a 2 inch diagonal (much longer distance would be needed). With my fsq85 as long as you can focus it, due to the design the lens spacing is always correct (without a reducer) meaning it is an excellent fast flat field scope for visual like your Genesis. I use reducers for visual with my c11 but they have much longer spacing distance.

2 minutes ago, Deadlake said:

So on planets I’d imagine your EdgeHD 11 would be better then all your APO’s or does seeing get in the way? 😃

Interestingly not, for planetary I much prefer my bigger refractors to my c11, the views are crisper. Maybe seeing (or lack of it) is a factor.

10 minutes ago, Highburymark said:

Am I missing something? All the table above suggests is you have to buy a 6” or larger apo to get a 9/10 rating. Ratings are almost completely related to aperture. It’s meaningless.

That’s works for me 😀

Actually my experience with a range of refractors is that aperture really is key when you get to a certain level of quality….

59 minutes ago, Deadlake said:

I wonder how competitive it would be with a FSQ-85 when being used with NV. I think the FSQ-85 F5.5 versus F6 would give better results when used in low SQM area for HA nebula, however where not so much gain needs to be deployed maybe a lot closer. But given the price good compromise  for a lot of people...

Field curvature. Plus with nv you want fast speeds at dark sites as well as lp sites.

Here is a link to a blog I wrote for Televue which describes how you can use a night vision device for astronomy

https://televue.com/televueopticstalk/2019/02/27/night-vision-in-the-uk-seize-the-night/#.YWhWw6TTUWM

Moi? 😉

Very pleased that you are happy with the pvs-14 @vineyard

Enjoy the night vision journey - it’s very cool 😀

And Orion with a certain horsey is now appearing in the early hours. Plus the Rosette which I think is my favourite nebulae - just a fabulous looking thing

Here’s another experiment with a higher frame rate than the ones I did before. This time is was the iconic horsehead which is now making an appearance in the early hours.

I’m a bit of a refractor fan having 40mm, 60mm, 76mm, 85mm, 92mm, 130mm and 160mm fracs.

As a general “cover all bases well” (lunar, planetary and DSOs) my preference is my AP130GTX which at f6.3 is still easy to lift, mount, transport etc. Obviously it still has limited aperture compared to a big dob but for me it’s the best compromise for a refractor. (In practice I would also want a 10-12 inch reflector of some description for galaxies, smaller nebulae etc). 
 

As a grab and go, I’ve found 100mm fracs (I’ve previously had a Tak fc100df and fc100dl) a bit too on the long side, particularly if I want to take it on a plane. So my preference for this role is an 85mm to 95mm. I did have all of the Baader 95mm tc, AP Stowaway 92mm, Tak Fsq85 and tv85 at the same time and enjoyed using them all and comparing them side by side. However, I knew that I was duplicating myself a lot at this aperture so made the decision to reduce the number.

The fsq85 was the last one I bought and it’s flatfield and fast f5.3 pairs with night vision use fantastically - it’s also really nice for planetary even with the limited aperture. So this is my preferred scope for overseas trips. 

The tv85 was my first refractor and I really liked it but it just wasn’t up to the quality of the others, so I sold it.

Finally, I decided I would pick between the stowaway or the Baader. I sometimes find over time my opinion changes with more use, and this happened with the Baader. Initial impressions were very positive and maybe there was a tiny tiny edge on lunar observing to the AP. But the Baader being f5.9 and having a shorter focal length did show more field curvature than the AP (both with and without Nv). The feathertouch focuser of the Stowaway is imo superior to the Baader focuser and generally I preferred the build quality of the stowaway. When I reflected on my observing sessions with each scope I just found that I had more fun with the Stowaway than the Baader. So I sold the Baader.

The fsq85 and Stowaway are the best scopes at this travel/grab and go aperture for me but obviously it’s just my personal opinion. Also I only do visual not AP (apart from some phone pics!). They are both keepers!

A bit of thread resurrection (only 4 years 😃) but my first light comments regarding the AP130GTX focuser not being as good as a feathertouch have continued to bug me - until today!

The AP130GTX has become my favourite “all rounder” scope. Quite easy to mount, pretty light, short with a decent amount of aperture for a refractor. It can give fantastic planetary and lunar views but is also great for DSOs (with or without nv).

However the stickiness of the focuser has always been a bit of an annoyance to me and, in fact, reduced my enjoyment of this scope. 
A few weeks ago, I finally contacted Astro physics direct in the USA about it. After an exchange of emails the technical guy assured me that my focuser seemed fine. However, another employee followed up my query and said that they could provide another focuser if I wished. Since I am delighted by every other aspect of this scope, I decided to bite the bullet and purchase a new focuser. 
It arrived today and very pleasingly is buttery smooth like my feathertouches on my other scopes. It took me about 2 minutes to install it and I’m very happy. After over 4 years, finally this scope has the focuser it deserves!!! And it just shows that sometimes I need to trust my instincts that something is just not right...

I had my ovni-m night vision for six months now and have written a detailed 5 page review of it for Astronomy Now magazine. 
 

Here’s a link where a digital copy can be ordered.

https://shop.astronomynow.com/product/an-June-2021/
 

And some “sneak peek” shots of the actual article taken from the astronomy now website.

1 hour ago, Deadlake said:

Excellent pictures as usual @GavStar. Buried in EEVA I didn’t see them till today. Obviously some discussion before I joined but why not post in DSO section where more accessible? The intensifier is just like an eye piece in use, i.e. it walks talks and quacks like one. Putting NV in EEVA is a classification similar to making all pics taken with an OIII filter in a separate section, it’s just another tool for visual observation. NV is different to EEVA as not stacking taking place.

Rant over.

@GavStar Where did you observe, London?

How so you feel the viewing would be using your FSQ-85 versus the AP stowaway I guess you used here?

Do you feel the slower speed of the AP was lead to more frequency shift in the image?

All the best

Martin

 

Martin, 

I guess you haven’t read this (pretty long!) thread? I think it answers your question about why I posted these nv videos in this section 😀. Basically sgl does not allow nv posts in the observing section even if it is properly signposted. Any nv posts in the observing sections are moved to eeva by the mods.

The first videos were from pretty dark skies in Isle of Wight, and the second set in the subsequent post were from London.

With the 67mm eyepiece the stowaway is operating at f2.6 so pretty fast and it does give very nice views with pretty minimal fc. My Baader 95mm didn’t work with nv as well for reasons I’m not sure about hence I decided to sell it and keep the stowaway. However for normal visual the Baader was great, with no discernible difference in quality of views to the Stowaway.

My Fsq85 operates at f2 with the 67mm so gives nearly twice as bright a view as the stowaway with nv. This means I can turn the gain down a bit more to reduce noise/scintillation even further, so maybe get a bit better live views and hence video recordings. The iPhone is pretty poor at recording the live views even with a 1 second exposure time and the actual live views in the eyepiece are more detailed, completely stable and very natural.

As Peter says I was using a very narrow 3nm ha filter to maximise the contrast of the nebulae and make it bright through the eyepiece. Nebulae are much trickier to capture as a video than globs/galaxies etc since the narrow ha filter results in more scintillation and light starvation which is a challenging situation for the iPhone camera. I have done 30fps videos of globs and brighter galaxies with night vision reasonably easily from very light polluted sites, as per below (the phone camera exaggerates the scintillation- in practice the gain can be adjusted on the nv monocular to effectively remove the scintillation visible)

I’ve own both the padded soft round and padded soft rectangular bags. I much prefer the round cylindrical style - easier to manoeuvre and much less bulky.

I’d suggest something like this

https://www.teleskop-express.de/shop/product_info.php/info/p7263_TS-Optics-padded-transport-bag-for-telescope-tubes-up-to-79-cm-length---35-cm-OD.html