Using Night Vision monoculars with a full moon

[GavStar]

So it’s nice and clear here but lit up majestically by the full moon (very strong shadows showing on the ground)

I’m using my 100mm refractor and have done some short comparisons of NV vs no NV. 

First up my current goto object, the horsehead. Not as obvious as it has been before but still there with a 7nm h alpha filter as shown in the iPhone photo below. Obviously nothing with a standard eyepiece.

Then I went onto m81 and m82. With a standard eyepiece they were a real struggle to make out, almost invisible. With NV very clear using a baader 685 filter as shown below. So NV does improve galaxies significantly.

Next up was the double cluster. NV showed more stars but the standard eyepiece was giving a more attractive view since plenty of stars were shown and the star shapes were much tighter. 

So I won’t be selling off my standard eyepieces yet!

 

[MarsG76]

Oh man.. now I want a night vision monocular...

 

[RobertI]

Very good results! Sorry if I missed your original posts, can you say what NV monocular you were using and how you attached it to the scope?

[alanjgreen]

Gavstar,

Good effort to get some pictures. Questions...

Is that the most magnification you can get out of the NV? 

- obviously it's ok for nebulas but compared to a big dob the galaxies would be too small for me 

So, can you get m81 to fill or even half the FOV size?

Alan

[Paul73]

The HH with an iPhone! With a full moon!! With 100mm!!! I haven’t realised that the difference would be of that magnitude.

Outragous. Well worth the £££££.

Presumably, you can pop one of these NV jobbies in any scope. So in a 16” Dob.......

Paul

[Paz]

 

3 hours ago, MarsG76 said:

Oh man.. now I want a night vision monocular...

 

Me first!

Will NV fever become the new aperture fever?

[Stu]

More great results Gavin, quite amazing that you can get the Horsehead even with a full moon, and in such a small scope too.

To Alan's point, for small objects it's not a replacement for a big dob, but clearly you wouldn't see the Horsey in a big dob under a full moon, so it has its place. As Paul says, imagine what would happen if you stuck it in the dob, and not a 100mm frac!

[GavStar]

Robert, here’s a link which gives details of my night vision set up.

Alan, you can use more magnification, just change the eyepiece to say a 18mm rather than the 55mm plossl I was using. However this reduces the contrast. I should have tried this out last night - will do next time to see the impact it has.

Paul, yes I’d like to use this on a big dob in at a dark site...

[MarsG76]

2 hours ago, Paz said:

 

Me first!

Will NV fever become the new aperture fever?

might just as well be the new fever.. but using electronic for viewing, is it really the same thing.. but who cares.. GIMME!!!!

[alanjgreen]

3 hours ago, Stu said:

More great results Gavin, quite amazing that you can get the Horsehead even with a full moon, and in such a small scope too.

To Alan's point, for small objects it's not a replacement for a big dob, but clearly you wouldn't see the Horsey in a big dob under a full moon, so it has its place. As Paul says, imagine what would happen if you stuck it in the dob, and not a 100mm frac!

But the max 40 degree FOV would make it impossible to use really. Think of all that nudging. If you are also stuck with a 55mm plossl then I would also seem to not be able to get very close up. Dob with tracking would be mandatory if you want to spend any time observing and not spend all the time chasing!

There seems to be some ideal sweet spot scope and I am trying to work out what it is.

Sounds like a good match to my old cpc1100 maybe? (Plenty of aperture, tracking and an 18mm EP would give decent magnification)

 

[alanjgreen]

2 hours ago, GavStar said:

Alan, you can use more magnification, just change the eyepiece to say a 18mm rather than the 55mm plossl I was using. However this reduces the contrast. I should have tried this out last night - will do next time to see the impact it has.

Paul, yes I’d like to use this on a big dob in at a dark site...

Thanks. How do you calc the magnification for the 55 and 18mm?

is it still scope focal divided by EP focal or now something else?

[scarp15]

Interesting read in comparing this emerging technology with eyepiece observing and highlighting strengths and weaknesses for both approaches. For some, this may become a new facet for observing.

My own perspective and having read the Cloudy Nights debate, is that it just seems to be a bit too casual in comparison with the traditional interpretation for observing, in gaining a sensation - collecting photons that connect directly, responding to light entering the rods and cones in your retina. In this analysis, accepting therefore weaknesses and limitations through visual sensitivity and that there will be some things however hard you try you may not get to see, except in images. Would I be interested to assume that I could observe the Horse Head Nebula from home and even through a full moon phase, personally no. In my backyard I like to observe the moon and whatever else is possible, for anything else, I am passionate for venturing to dark sky locations and accepting the visual outcome. For those that are excited by this technology and can afford to invest in it, yeah it will have its place, borrowing slightly an analogy from Cloudy Nights, do you prefer mountain biking or motocross.  

[GavStar]

56 minutes ago, alanjgreen said:

But the max 40 degree FOV would make it impossible to use really. Think of all that nudging. If you are also stuck with a 55mm plossl then I would also seem to not be able to get very close up. Dob with tracking would be mandatory if you want to spend any time observing and not spend all the time chasing!

There seems to be some ideal sweet spot scope and I am trying to work out what it is.

Sounds like a good match to my old cpc1100 maybe? (Plenty of aperture, tracking and an 18mm EP would give decent magnification)

 

Alan

This link gives details of someone using a 20 inch dob with NV optics together with pictures showing comparisons of different magnifications. Short focal length seems to be key for NV and therefore scts generally aren’t used in USA with NV.

http://www.loptics.com/articles/nightvision/nightvision.html

[GavStar]

52 minutes ago, alanjgreen said:

Thanks. How do you calc the magnification for the 55 and 18mm?

is it still scope focal divided by EP focal or now something else?

Just scope focal length divided by ep focal length. So I was using a 740 focal length scope with 55mm giving 13x and 18 would give 41x

[Stu]

1 hour ago, alanjgreen said:

Sounds like a good match to my old cpc1100 maybe? (Plenty of aperture, tracking and an 18mm EP would give decent magnification)

From my understanding, a fast focal ratio is beneficial for NV observing; it is best though of along the lines of imaging from that perspective. In the TEC160 with the 55mm Plossl I think it is working at around f3.5, so a fast Newt would probably be better.

[YKSE]

Very nice report, Garvin

Have you tried the 3x intensifier?

[Paul73]

Ok. I am a complete Luddite, and regard the answer to most observing issues to be ‘buy a bigger mirror’, but couldn’t this could transform travel setups???

Paul

ps. The snaps / short exposure pics are incredible.

[alanjgreen]

2 hours ago, GavStar said:

Alan

This link gives details of someone using a 20 inch dob with NV optics together with pictures showing comparisons of different magnifications. Short focal length seems to be key for NV and therefore scts generally aren’t used in USA with NV.

http://www.loptics.com/articles/nightvision/nightvision.html

Thanks. But am I right that I would only get 40 degree FOV? I would think that this limits the magnification that I would use to avoid nudging hell (as it's a manual dob).

i have discovered that galaxies look great at x250 in the big dob. But with a tiny FOV this level of magnification is only really useful with tracking.

[GavStar]

Yes only 40 degree fov Alan which is dictated by the fov of the image intensifier tube. I think generally NV is generally used for big objects rather than high magnification. But I will have a go at using higher magnification on m81. I think I will struggle at 250x though ?

[GavStar]

1 hour ago, YKSE said:

Very nice report, Garvin

Have you tried the 3x intensifier?

Yes I’ve tried the 3x magnifier. But I think this would be better at darker sites for sweeping large nebulae. Also it does vignette at the edge when using filters (which are a necessity for nv)

So far, attaching the NV to a telescope has been the best outcome for me at light polluted sites.

[GavStar]

1 hour ago, Paul73 said:

Ok. I am a complete Luddite, and regard the answer to most observing issues to be ‘buy a bigger mirror’, but couldn’t this could transform travel setups???

Paul

ps. The snaps / short exposure pics are incredible.

My exact thoughts Paul. I’m hoping to travel to Tenerife later this year and I will only be able to take my tv85 with me. With the NV setup i will expand my viewing options considerably.

[alanjgreen]

2 hours ago, Stu said:

From my understanding, a fast focal ratio is beneficial for NV observing; it is best though of along the lines of imaging from that perspective. In the TEC160 with the 55mm Plossl I think it is working at around f3.5, so a fast Newt would probably be better.

I have had a play with FOV using sky safari. I setup several EPs at 55mm, 24mm, 13mm and 10mm with a 40 degree FOV. Then I got it to display the FOV circles based on my dob (with paracorr) focal length of 2089mm. 

- galaxies were fitting nicely into the 24 (I have a pan24) and the smaller ones were ok in the 13mm but the 10mm looks too small to hold objects in the FOV for long.

- I could just about get the Flame into the 24mm 40 degree fov. No alnitak or horse Head!

I had to add a 55mm 40 degree FOV eyepiece to get a FOV that could take the flame and horse head (but it was tight, nothing like the small patch in the centre of the FOV you see in gav's pictures above.

with the 55mm providing x38 magnification and the 24mm providing x87, at least nudging won't be a problem  

But, I get the feeling that you would ideally need a dob at f3.0 or even less (Mine is f3.6) if you needed more magnification.

It will be interesting to see if any manufacturer catches onto the potential astronomy usage and looks to make kit capable of wider than 40 degree FOV. Perhaps we need to start a petition?

[alanjgreen]

9 minutes ago, GavStar said:

My exact thoughts Paul. I’m hoping to travel to Tenerife later this year and I will only be able to take my tv85 with me. With the NV setup i will expand my viewing options considerably.

Yep, it will work well in my Borg89  

[GavStar]

6 minutes ago, alanjgreen said:

 

It will be interesting to see if any manufacturer catches onto the potential astronomy usage and looks to make kit capable of wider than 40 degree FOV. Perhaps we need to start a petition?

Unfortunately I think that’s unlikely. The intensifier tubes were developed for military use and that’s where the vast majority of the demand comes from (plus hunting). I think us amateur astronomers will just have to piggy back on that.

It would be nice if I was wrong though. Some old tubes were 50 degree fov but at normal 1x or 3x use I guess the logic is that 40 degrees fov is fine.

I don’t think I’d government was thinking about magnifing to 250x when it was setting it’s requirements.?

[GavStar]

13 minutes ago, alanjgreen said:

Yep, it will work well in my Borg89  

Thinking of getting a NV monocular then Alan? ?