79 replies to this topic

[C.Hay]

OK, thanks. Wolf 3s is green phosphor? Will the Wolf 3s work in prime focus mode with a c-mount to 1.25 inch adapter (+all the needed filters)?

Yes, green. So is the Zeiss. I and all the other observers I know who use it don't find the green intrusive at all. In fact, we find one forgets it after twenty seconds and also doesn't have a coloured memory of the image.

 

Works fine in prime focus, just like an OVNI - screw off the lens, put on 1,25 inch adapter such as the one made by Baader. This is totally unproblematic with the Wolf 3. With the Zeiss device, with its recessed mount, you need an adapter that is slightly longer than the Baader one and doesn't have a collar around the male C-mount thread, this one for instance from TS: https://www.teleskop...uf-C-Mount.html

 

Whether H-alpha filters will then do you any good depends on how fast you can make your system. f/4 and slower increasingly kills the nebulae. Globs and galaxies (at least the parts emitting in red/infrared; Gen2+ has low performance in the blue) remain good.

 

A warning: Try before you buy. These are second-hand devices that can be 15 years old or more. Sellers are often inheritors who don't know anything about them and can't gauge whether they show a good image of the sky - especially not what happens with an H-alpha filter. If you have a return option, fine. But if not, I'd insist on trying it out under the night sky and putting an H-alpha filter on. When last on the market, a Wolf 3 with lens cost about 3400 Euros. A normal price nowadays would be around 800.

 

CS, Christopher

Edited by C.Hay, 22 June 2023 - 07:39 AM.

[Joko]

just like an OVNI

 

Thank you for trying to compare your device to an OVNI-M but it would be helpful to explain that there are major differences.

I'm not going to list all of them nor everything that can be done with an OVNI that can't be done with your device because that would sound like an advertisement.

But one of them is TFOV. Up to 90° with an OVNI and something like 16° with the Zeiss and 21° with the Wolf 3.

 

It's definitely not like an OVNI.

 

And we've already come across counterfeit products on British and Chinese websites. Of course, none of their products were even close to ours.

 

No, no, OVNI states very clearly that they are a French company, very good.

OK, so prices are as listed on the website (plus shipping obviously)?

So if I decide I want it, do I contact them, or you?

By e-mail, from the website or from the official Facebook group/page. I'm pleased to help you make the right decision.

Edited by Joko, 22 June 2023 - 08:39 AM.

[Uwe Pilz]

> Up to 90° with an OVNI and something like 16° with the Zeiss and 21° with the Wolf 3.

 

The Wolf-3 accepts other C mount lenses, so you may change the magnification and therewith the true FOV. For the Zeiss, you are right.

[Armanos]

Yes, green. So is the Zeiss. I and all the other observers I know who use it don't find the green intrusive at all. In fact, we find one forgets it after twenty seconds and also doesn't have a coloured memory of the image.

 

Works fine in prime focus, just like an OVNI - screw off the lens, put on 1,25 inch adapter such as the one made by Baader. This is totally unproblematic with the Wolf 3. With the Zeiss device, with its recessed mount, you need an adapter that is slightly longer than the Baader one and doesn't have a collar around the male C-mount thread, this one for instance from TS: https://www.teleskop...uf-C-Mount.html

 

Whether H-alpha filters will then do you any good depends on how fast you can make your system. f/4 and slower increasingly kills the nebulae. Globs and galaxies (at least the parts emitting in red/infrared; Gen2+ has low performance in the blue) remain good.

 

A warning: Try before you buy. These are second-hand devices that can be 15 years old or more. Sellers are often inheritors who don't know anything about them and can't gauge whether they show a good image of the sky - especially not what happens with an H-alpha filter. If you have a return option, fine. But if not, I'd insist on trying it out under the night sky and putting an H-alpha filter on. When last on the market, a Wolf 3 with lens cost about 3400 Euros. A normal price nowadays would be around 800.

 

CS, Christopher

OK. Does the Wolf 3s have a manual gain functionality? How large is the AFOV, when you look into the eyepiece?

[Uwe Pilz]

The wolf comes with a 50 mm lens and has a 25 mm eyepiece, as usual. That is a magnification of 2x and an FOV of slightly more than 20 deg.

 

There is no manual gain control so you have to live with the automatic.

[C.Hay]

Dear me, Joko, I really wasn't implying that these devices are the same as an OVNI. The only similarity I was seeking to clarify is that the lens is interchangeable on the Wolf. And please don't get me wrong, I'm not arguing against an OVNI. I'm merely pointing out that there are options for those on a tighter budget.

 

Joko and Uwe, I must correct you both about TFOV. The Zeiss has 8.3° at 5.6x and no further options. The Wolf 3 has 41° at 1x, 21° at 2x and so on.

 

Joko, you mention up to 90° with an OVNI. Is this acheived by reducing magnification below 1x? I am not doubting, but truly curious, as I have a friend who is very interested in procuring an OVNI.

 

Regards, Christopher

Edited by C.Hay, 23 June 2023 - 09:13 AM.

[sixela]

Is this acheived by reducing magnification below 1x?

 

Yes. C-mount objectives exist in focal lengths well below 25mm.

[Armanos]

Dear me, Joko, I really wasn't implying that these devices are the same as an OVNI. The only similarity I was seeking to clarify is that the lens is interchangeable on the Wolf. And please don't get me wrong, I'm not arguing against an OVNI. I'm merely pointing out that there are options for those on a tighter budget.

 

Joko and Uwe, I must correct you both about TFOV. The Zeiss has 8.3° at 5.6x and no further options. The Wolf 3 has 41° at 1x, 21° at 2x and so on.

 

Joko, you mention up to 90° with an OVNI. Is this acheived by reducing magnification below 1x? I am not doubting, but truly curious, as I have a friend who is very interested in procuring an OVNI.

 

Regards, Christopher

OK, thanks. But what is the APPARENT FOV, like what you see when you look into the eyepiece? Standard 50-60°? Maybe 40°?

What is the eye relief, like how close to the eye you need to place the eyepiece?

And what about the distortion of the image? Any barrel distortion? Pincushion? Any vignetting (darkening on the edge)? How flat is the field of view, any blurred edges?

Edited by Armanos, 23 June 2023 - 04:12 PM.

[sixela]

40°, unless you plan to customize the eyepiece side of the NVD device (which is harder than you think, because you need to precisely match the field curvature of the original eyepiece, precisely because it is desgined to avoid field curvature; how precise it has to be depends on your own eye's capacity to accommodate for focus changes.) So you'll get a true FOV of 90° at slightly less than 0.5x.

 

There are some 50° AFOV eyepieces that you can buy, these would likely work if you can make them fit (and get the distance right). Not sure if Joko has ever tried these alternatives.

 

Eye relief is somewhat tight for glasses users on an OMNI-V. A friend needs to flip the eyeguard and press his glasses onto the (rather thick) flipped eyeguard; I'd estimate the usable eye relief is roughly 14mm (with the design eye relief at 18mm). You can gain some extra usable eye relief by putting an eyeguard on it from a cheap Plössl and flipping that down. I don't wear glasses and then you need to get the eye snug into the winged eyeguard.

A PVS-14 has slightly more eye relief, and I assume the OVNI-B also has more.

 

Those things are designed to pretty distortion free, and make a conscious choice to go for the circle condition (i.e. just enough pincushion distortion to compensate for the eye's usual barrel distortion, which also entails some angular magnification distortion at the edge). I find that it really isn't an issue (at 40° AFOV). It tends to depend on the objective a lot more, and if you use C-mount lenses (or even MFT or DSLR lenses) anything goes.

Edited by sixela, 23 June 2023 - 04:43 PM.

[Armanos]

Thanks, my bad, I should have calculated the AFOV from the FOV data (21°). 42° is a little tight, ain't it?

You are right about the field curvature, distortion, at this AFOV they are not an issue.

Eye relief is problematic for me (deep set eyes), I usually remove all the rubbers from my binoculars and eyepieces. But 14 mm is manageable.

I hope Christopher will chip in on the eye relief of his Wolf 3s.

Edited by Armanos, 23 June 2023 - 05:34 PM.

[sixela]

Then you might want to swap the eyeguard with that of a cheap €15 Plössl instead (bonus: you don't have to constantly orient the eyeguard differently when switching eyes or reinstalling it in the focuser).

Removing it completely is something I would not do without covering the top with something, especially if you plan to let someone with glasses use it (although I've seen people use thin felt on eyepieces for similar things). If you remove the original eyeguard the top is bare metal around the glass.

Edited by sixela, 23 June 2023 - 06:52 PM.

[Gavster]

 

 

Eye relief is somewhat tight for glasses users on an OMNI-V. A friend needs to flip the eyeguard and press his glasses onto the (rather thick) flipped eyeguard; I'd estimate the usable eye relief is roughly 14mm (with the design eye relief at 18mm). You can gain some extra usable eye relief by putting an eyeguard on it from a cheap Plössl and flipping that down. I don't wear glasses and then you need to get the eye snug into the winged eyeguard.

A PVS-14 has slightly more eye relief, and I assume the OVNI-B also has more.

 

 

The pvs-14 has 25mm eye relief vs 18mm for the ovni-m. In my actual experience of using both devices, the difference is more than slight. I found the pvs-14 noticeably more comfortable to observe with. But it’s obviously personal preference.

Edited by Gavster, 24 June 2023 - 12:25 AM.

[sixela]

I don’t wear glasses and personally find the 16mm Nagler T5 comfortable, and had to install an eyeguard extender to make the Apollo 11 comfortable, so I can see how our preferences would be different.

My friend (with glasses) was able to use the OVNI-M but hasn’t compared it with a PVS-14; I was just reporting his experience.

Edited by sixela, 24 June 2023 - 01:36 AM.

[Joko]

Dear me, Joko, I really wasn't implying that these devices are the same as an OVNI. The only similarity I was seeking to clarify is that the lens is interchangeable on the Wolf. And please don't get me wrong, I'm not arguing against an OVNI. I'm merely pointing out that there are options for those on a tighter budget.

 

Joko and Uwe, I must correct you both about TFOV. The Zeiss has 8.3° at 5.6x and no further options. The Wolf 3 has 41° at 1x, 21° at 2x and so on.

 

Joko, you mention up to 90° with an OVNI. Is this acheived by reducing magnification below 1x? I am not doubting, but truly curious, as I have a friend who is very interested in procuring an OVNI.

 

Regards, Christopher

Hi Christopher,
Don't worry, there may be confusion on my part too by reading your post too quickly.

 

The maximum of 8.3° with your NV device is very very narrow but the most important thing is that you like your NV device.

 

To answer your question about the OVNI-M, you can go up to 90 degrees using a short focal length lens of less than 26mm. Yes, this will reduce the magnification but that's not a problem as I would mainly recommend this configuration for 3 types of NV applications :

• space domain awareness to detect and observe space debris / satellites. This is one of the professional uses of our NV eyepieces.
• meteors observation for amateur NV users.
• TLE observation like sprites, jets and others TLE. Something I've never done but hope to one day 😃 Cnoct on this forum is the world's NV expert of these phenomenas. Some of his videos are breathtaking. For example : www.youtube.com/watch?v=QeFQCg_Mma8

Edited by Joko, 24 June 2023 - 03:22 AM.

[C.Hay]

Joko, thanks for the roundup of 90° uses, very interesting! What does TLE stand for?

 

Armanos, I use glasses to observe and find the eye relief on the Wolf 3s with folded-down eyecups pleasant. I've tried three specimens, they all behave the same in this regard. I wear thin glasses and don't have very deeply recessed eyes. If you're observing without glasses it should work fine.

 

Christopher

[Joko]

Joko, thanks for the roundup of 90° uses, very interesting! What does TLE stand for?

TLE stands for Transient Luminous Event.
More info here : https://en.m.wikiped...heric_lightning

[Armanos]

Thanks everyone. I made an impulse buy - the Bushnell Wolf 3s device. The deal is not over yet, I hope I will not receive a total lemon. It was from a reputable hunting store. Wasn't cheap, btw.

[WheezyGod]

Thanks everyone. I made an impulse buy - the Bushnell Wolf 3s device. The deal is not over yet, I hope I will not receive a total lemon. It was from a reputable hunting store. Wasn't cheap, btw.

Did you get any say about specs and/or spots?

[Armanos]

No. I am afraid the guy would not tell, he is an armorer. I said it was a total impulse. But if it's really bad I am sure I can return it.

[Joko]

Did you get any say about specs and/or spots?

Old GEN2 technology has low specs and are rarely supplied with specs sheet.
Best specs for these tubes are around : FOM 800, gain 10000, photocathode sensitivity 600, Resolution 40, SNR 20, EBI 2...

Which is extremely far from the devices used by NV astronomers on this forum.

Edited by Joko, 25 June 2023 - 04:31 AM.

[25585]

As for optical, I would need long effective eye relief from whatever is the topmost layer on a NV device. That is always #1 for me, as I wear glasses.

 

Are there any eyepieces, apart from Tele Vue, that work for afocal with NV devices?

[sixela]

The output and input sides are completely decoupled with an NVD. The eye relief (if you want to see the whole fibre optics network output, i.e. field of view of the NVD) is entirely set by the eyepiece behind the NVD tube.

 

Gavster says that the eye relief of a PVS-14 vs. an OVNI-M is 25mm vs. 18. Knowing what eyepieces you find troublesome (even "high eye relief" ones) I'd bet you'd find a PVS-14 more comfortable.

 

You should ask Joko, but chances are that you'd find the OVNI-B with shorter eyecups more comfortable than an OVNI-M, and that if you got a device from him that would be the more obvious choice. He can probably chime in and tell you the eye relief of the OVNI-B eyepieces and how much useful eye relief you can get using really minimal eyeguards. It's a bit tricky because the eye relief specs of the normal PVS-7 was also only 15mm...

Edited by sixela, 25 June 2023 - 08:21 AM.

[C.Hay]

Thanks everyone. I made an impulse buy - the Bushnell Wolf 3s device. The deal is not over yet, I hope I will not receive a total lemon. It was from a reputable hunting store. Wasn't cheap, btw.

Oho, I guess that was prompted by my advice, so I do hope it works out for you. Which lens is supplied with it? If you're aiming to use it handheld, I'd warmly recommend going to at least a 50mm lens, which gives 2x, and preferably trying out a 75mm lens as well, which gives 3x. Every such step in magnification makes a major difference in what you'll see. And take care to go for lenses of f/1.4 or faster.

 

If you're interested in handheld, widefield observation of H-alpha nebulae, you may profit from preshifted filters. Front-mounted is the way to go, as there isn't enough room between lens and device. I've produced a series of filter reviews comparing different bandwidths and preshifted against non-preshifted filters for 1x, 2x, 3x and 5x here:

https://www.cloudyni...ge-true-fields/

 

CS, Christopher

[Armanos]

It was in part prompted by you, but also by other considerations (budget). As I said the deal is not over, I am not sure I will even get it - it depends on how export/import goes, bad things can happen there..

It has the standard 50 mm lens, but it is slightly different from yours (it has made in japan on it); the device is also slightly different from yours, it has a different rubber armoring, logo, and the eyeguard (shorter). There seems to be three types of this device, not sure what that means. If and when I get it, I may peak inside to see what amplifier tube it has.

[Armanos]

Oho, I guess that was prompted by my advice, so I do hope it works out for you. Which lens is supplied with it? If you're aiming to use it handheld, I'd warmly recommend going to at least a 50mm lens, which gives 2x, and preferably trying out a 75mm lens as well, which gives 3x. Every such step in magnification makes a major difference in what you'll see. And take care to go for lenses of f/1.4 or faster.

 

If you're interested in handheld, widefield observation of H-alpha nebulae, you may profit from preshifted filters. Front-mounted is the way to go, as there isn't enough room between lens and device. I've produced a series of filter reviews comparing different bandwidths and preshifted against non-preshifted filters for 1x, 2x, 3x and 5x here:

https://www.cloudyni...ge-true-fields/

 

CS, Christopher

Thanks, I read your study on filters.

I intend to do handheld viewing, as well as prime focus in a f/5 refractor.

What are the best general filters to get? H-alpha is obvious, but wouldn't an UHC filter be better?

UHC has both O-III and H-alpha bands.

Edited by Armanos, 26 June 2023 - 01:23 AM.