First light - Nikon 180mm lens with QHY9 and EFW - and custom made adapter - pic heavy

[tooth_dr]

A few months ago I bought an M42 adapter to connect a nikon lens to my QHY9 CCD.   When I added in the filter wheel to the imaging train, the lens was a few mm too far from the CCD sensor and I couldnt get it to focus at infinity.  I set about working out how to get it to focus.  I figured out that if I could screw the whole adapter into the filter wheel then I could gain probably 5mm of back focus.  The current nikon lens adapter was an M42 thread, but the body itself was large enough to cut an M54 thread externally.  I could then thread that adapter into the EFW casing.  I had to be careful not to foul the filters inside at the same time. This adapter replaces the M54-M48 (or M54-M42) adapter that comes with the EFW.

I couldnt do this myself so I sent a fella I know a message about it, and he was happy to try and sort it out.  We met up a couple of times, and he took some measurements, and set to work on it.

I wasnt in a panic, so a few months went by, with me finally getting it 3 weeks ago.  In between times I bought another used QHY9 and matching QHY EFW.  It is a 5 x 2" wheel which is perfect for the KAF-8300 sensor size at a potential F2.8.  I had a luminance filter already, and I picked up a 2" Baader Ha filter off here a couple of weeks ago.  I'm still looking for RGB filters.

In between times I had lent the QHY9 to xiga off here, so when he was finished with it a week and a half ago, I got it back and set about connecting all together.  I wasnt sure if it would focus at infinity, but initial testing looked positive.

I had my first session on Thursday night with it, and it focused fine at infinity with the 180mm lens at F2.8, with just the expected amount of extra travel past infinity.  I 3d printed a microfocuser but it's a mm too narrow in diameter to fit over the barrel, so I might just rub it down later with a file to get sufficient clearance.  It's virtually impossible to turn the focus ring by hand at small enough increments, but I got as close as I could with a Bahtinov mask.  I dont have any calibration data yet - I went to get it today but the camera is sitting at 19 deg C and since I run at -20 deg C, it might just push the camera power a bit too far for my liking as it only does a -40 delta T.

There is no longer a locking button that normally locks the lens in place.  I have the camera supported on the dovetail so there is no pressure on it, and it cannot easily turn.  The overall fit of the adapter is tight, and not loose like the way a normal camera lens feels when you connect it to a camera body.  My friend could have made it, but it just wasnt needed.

 

I'll post a few images of the adapter, how it was made up and how it fits into the imaging train.  I painted it black and rubbed it down with fine sandpaper to prevent reflections.  My friend had planned to anodise it for me, but his factory machine was out of order, and with no repair timeframe, I was happy enough to paint it myself.

The image itself is 6 x 20 minutes, 7nm H-alpha filter.  QHY9 mono KAF-8300, with Nikon 180mm lens at F2.8.  Stacked in APP.  I didnt get the pre and post meridian flip platesolving done, so the frames dont all match up, but you can see the FOV of the KAF-8300 and 180mm lens.

I plan to run this alongside my Epsilon and ED80, which both have KAF-8300 sensors, and try to produce a variety of views of the nebulae.

 

 

Hope this is of interest to anyone attempting the same thing.  It also works with my Atik EFW2, which is 22mm thick.

 

Original purchased Nikon lens to M42 adapter off ebay for £10 (or less cant remember exact cost) - it was used for the lens connecting parts

 

New adapter being made, my friend informed me he turned all the threads by hand.

 

Completed adapter:

 

A few photos of equipment attached:

 

Edited July 25, 2020 by tooth_dr

[david_taurus83]

That's an envious setup you have there Adam! It looks like something out of a professional scientific observatory.

Edited July 25, 2020 by david_taurus83
spelling

[ultranova]

Well done on getting a adapter made...I dare say...there could be a outlet for that kind of adapter...as I have come across the same problem of reaching focus..

I am sure I am not alone on this...

The Ha photo looks very good indeed.

Well done

Paul

[x6gas]

Nice bit of turning your mate did on that adapter, Adam.  Cutting the threads "by hand" on a lathe (which means turning the lathe by hand) is pretty common as it gives excellent control.

And the image looks brilliant!  Clearly a nice piece of glass...

[tooth_dr]

Second attempt at imaging with the Nikon lens and QHY9 mono camera.  Wasn't a great night with the dome not moving to where it was supposed to go, and by the time I faffed about with that the clouds came in.  The guiding was all over the show, and the moon was ?full.  Not worth starting a new thread, so will just catalogue them here.

M16 - 60s sub in Ha

NGC7635 - 1200s sub in Ha

 

 

Edited August 4, 2020 by tooth_dr