Night vision with a 16 inch dob

[GavStar]

My favourite scope to use with my night vision monoculars is I think my C11 which has given me some fantastic views with a 0.75x reducer and 55mm plossl (effective system speed f3.3).

However, I had a dose of aperture fever last year and ordered a 16 inch goto dob manufactured by sky vision in France.

It turned up late last year and as it was my first dob I was a bit shocked by the size and bulk of it.

I had a couple of goes with it but struggled with the coma corrector spacing (I had the Es one) and was a bit disappointed with the nv views it gave since the edge stars were not great.

The scope got mothballed for a few months.

Then events happened which enabled me to take it to my dark sky site for further testing. I purchased a Televue paracorr which increases the f ratio of the scope a little but enabled me to be more confident about getting the coma corrector working properly.

I set the scope up carefully following the paracorr instructions and with an ethos in non nv mode the views looked good across the field of view. However once I moved to the nv monoculars and 41mm panoptic the star shapes at the edge weren’t great. I was disappointed. I checked the paracorr instructions and I’d done everything right. I checked the collimation again and it was a bit out. After adjusting and redoing collimation twice I eventually got decent stars with the panoptic.

Are nv monoculars more sensitive to non-accurate collimation than normal glass eyepieces?? I think using the night vision monoculars in afocal mode with an eyepiece does impact the edge of the fov to some extent.

Anyway after a few hitches with the goto setup I eventually got everything working well. By this time it was getting very late so I only managed a few objects in Cygnus.  But they looked rather nice - a step up in resolution to my c11 phone images I think and the visual views are also noticeably better.

Here are phone images of the Pac-man, eastern veil and crescent nebula.

 

I’m now looking forward to using this scope again despite it taking materially longer for me to setup compared to the c11.

[R26 oldtimer]

Very nice. Good to see you're posting again.

[Stu]

Nice images Gavin, glad you are getting to grips with the dob now. Particularly like the Pacman.

[Knighty2112]

Nice views. Out of curiosity which night vision monocular do you use?

[GavStar]

15 hours ago, Knighty2112 said:

Nice views. Out of curiosity which night vision monocular do you use?

It’s this one:

https://actinblack.com/pvs-14/

[RobertI]

Very impressive Gav, worth persevering for sure. Would be interesting to see a comparison of the same objects with your other scopes?

[DirkSteele]

Just wow.  I love the idea of this thing more and more every time I see more pictures that you have taken.  And that is after playing with your NV and already being very impressed with it.

[GavStar]

31 minutes ago, RobertI said:

Very impressive Gav, worth persevering for sure. Would be interesting to see a comparison of the same objects with your other scopes?

Robert, 

Here’s some comparison Pac-Man shots (85mm Tak, 130mm AP and the 16 inch dob)

 

 

A comparison with the Veil (Tak 85, tv85, c11, 16 inch dob)

 

 

 

A crescent comparison (Tak 85, c11, 16 dob)

 

 

[RobertI]

Great comparisons, thanks 👍

[Stu]

Yes, excellent comparisons, really shows the different merits of small scope for wider field and large aperture for more detailed views.

[PeterW]

Very nice, now need to find some smaller Sharpless to poke the 16” at. Sounds like we could have more NV users in the U.K. sometime.... put one on Santa’s list and be good!!

 

peter

[GavStar]

Some more phone pics with my 16 inch dob and new night vision monocular, taken recently with ovni-m (rather than my pvs-14 which I used for all the pics above). I think the ovni-m in prime mode gives sharper stars to the edge visually.

 

[Deadlake]

@GavStar Great pictures, taken last night? Nice you can do that when the moon is fully (~99%) out. 

[GavStar]

5 minutes ago, Deadlake said:

@GavStar Great pictures, taken last night? Nice you can do that when the moon is fully (~99%) out. 

No taken a few weeks ago with much less moon!

[Stu]

Fantastic pictures Gavin. Some of the best I’ve seen I think, great to see how you have improved your setup over time.

What is the Galaxy in the second image?

[GavStar]

Just now, Stu said:

Fantastic pictures Gavin. Some of the best I’ve seen I think, great to see how you have improved your setup over time.

What is the Galaxy in the second image?

Thanks Stu, as you know it’s taken me a while to get the dob set up to how I like but I think I’m there now, it’s almost grab and go 😀.

It’s the needle galaxy, one of my favourites and spectacular through the eyepiece of my dob.

[Stu]

19 minutes ago, GavStar said:

Thanks Stu, as you know it’s taken me a while to get the dob set up to how I like but I think I’m there now, it’s almost grab and go 😀.

It’s the needle galaxy, one of my favourites and spectacular through the eyepiece of my dob.

Good stuff. Looks like you got NGC4562 in there too 👍