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ASI6200mm adapter quest ... wandering the wilderness

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9 replies to this topic

#1 jeff.bottman

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Posted 04 August 2020 - 11:14 AM

I'm looking to augment my Nikon D750 with a mono full frame camera.  I've learned lots, made good images, and enjoyed the DSLR, and am now ready to add the ASI6200MM dedicated astro cam to my toolbox.  I very much want to use my Nikkor 300mm f/2.8 lens with the camera, but ZWO does not offer a Nikon mount adapter that plays with their filter wheel.  And of course, a filter wheel is HIGHLY desireable!

 

Has anyone out there found a solution to achieve:   (Nikon F mount lens)  to (2 inch filter wheel) to (ASI6200MM camera)?

 

I tried designing a Precise Parts adapter, but the requisite 9 mm length of the F-mount to 54mm adapter is not possible, according to their design tool.



#2 StephenW

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Posted 04 August 2020 - 01:34 PM

You may want this:  https://astromechani...ew_announcement

 

...once it's available, that is :)


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#3 Mat33

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Posted 04 August 2020 - 05:48 PM

I'm in the same boat as you wanting to use a Nikon lens with the ASI6200mm.  I was thinking of removing the tilt adapter, and this gives enough backfocus for a lens adapter such as the QHYCCD one with ASI6200mm 12.5mm- EFW 20mm-M54 spacer 4mm- QHYCCD Nikon adapter 10mm.  Alternatively it looks like AstroMechanics is making a dedicated EOS adapter for the ASI6200mm + EFW that includes a tilt adapter and you could use a EOS-F mount adapter for your Nikon lens although this would be more expensive and the EOS-F mount may be a less rigid connection.     See https://www.cloudyni...-efw-with-lens/


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#4 jeff.bottman

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Posted 04 August 2020 - 08:29 PM

Thanks for this info Mat33 (!!).  Suppose one were to not remove the tilt adapter.  Then the backfocus stack is 12.5 (camera) + 5 (tilt adapter) + 20 (filter wheel) + 10 (QHYCCD Nikon adapter) = 47.5 mm.  This is 1 mm over standard Nikon 46.5 mm flange distance.  Maybe the lens will reach focus with this small a difference ... or maybe not, what do you think?  My lens is the Nikkor 300mm f/2.8.

 

Update, I just checked my lens and it has a lot of range past the "infinity" mark.  So, it may be able to attain focus.  Then the question is whether optical abberations become significant.

 

 

I'm in the same boat as you wanting to use a Nikon lens with the ASI6200mm.  I was thinking of removing the tilt adapter, and this gives enough backfocus for a lens adapter such as the QHYCCD one with ASI6200mm 12.5mm- EFW 20mm-M54 spacer 4mm- QHYCCD Nikon adapter 10mm.  Alternatively it looks like AstroMechanics is making a dedicated EOS adapter for the ASI6200mm + EFW that includes a tilt adapter and you could use a EOS-F mount adapter for your Nikon lens although this would be more expensive and the EOS-F mount may be a less rigid connection.     See https://www.cloudyni...-efw-with-lens/


Edited by jeff.bottman, 04 August 2020 - 08:36 PM.

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#5 Mat33

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Posted 04 August 2020 - 09:54 PM

Hi Jeff, I think it might.  If you add 1mm for the filter thickness (assuming 3mm thick filters like chroma etc) then your back focus should be 47.5mm so it might just work.  However I was thinking its safer to be bit under the 46.5mm (or 47.5mm) rather than over. 

 

How have you found the 300mm f/2.8 -do you use it wide open?  Paired with the ASI6200 it will be an awesome wide field setup with pretty good sampling considering the FOV.

 

Mat



#6 jeff.bottman

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Posted 04 August 2020 - 10:22 PM

Hi Mat, the 300mm f/2.8 Nikkor is an underappreciated marvel.  I use it wide open and it's very very sharp.  The poor man's Tak FSQ106.  Actually, I measured the front lens at 105mm.  PixInsight FWHMEccentricity script shows around 2.5 pixels FWHM across the entire field ... corner to corner, for my 4000 x 6000 pixel full frame sensor (currently Nikon D750, soon to be ASI6200MM!).  I have several Top Pick images on AstroBin with this lens.  I paid a little over $1000 for mine, and consider that a really good deal for what I get.  If you want to take a look ...

 

https://www.astrobin...s/jeff.bottman/

 

Cheers, --Jeff

 

 

Hi Jeff, I think it might.  If you add 1mm for the filter thickness (assuming 3mm thick filters like chroma etc) then your back focus should be 47.5mm so it might just work.  However I was thinking its safer to be bit under the 46.5mm (or 47.5mm) rather than over. 

 

How have you found the 300mm f/2.8 -do you use it wide open?  Paired with the ASI6200 it will be an awesome wide field setup with pretty good sampling considering the FOV.

 

Mat

 



#7 Mat33

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Posted 05 August 2020 - 04:33 PM

Nice work Jeff-especially like your blue horsehead.


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#8 andysea

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Posted 06 August 2020 - 06:08 PM

The ASI 6200 with the tilt plate and the filter wheel will allow to attach nikon lenses with this adapter:

https://www.highpoin...aBoC4RQQAvD_BwE

I have astrodon filters in the FW.

 

I have used it with the Rokinon 135mm and it worked fine.

 

The photo shows the assembly, with a different Nikon lens. I put electrical tape around the tilt plate so that might look a bit confusing.

If you don't use  fully manual lens you will need a way to hold the aperture iris open. I am thinking to design and print a collar that would do just that.

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Edited by andysea, 06 August 2020 - 06:09 PM.

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#9 jeff.bottman

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Posted 06 August 2020 - 08:18 PM

Thank you Andy, I've already ordered the adapter!  And it's comforting to know it will actually work.  Looking forward to this new camera; I have lots to learn.  

 

The ASI 6200 with the tilt plate and the filter wheel will allow to attach nikon lenses with this adapter:

https://www.highpoin...aBoC4RQQAvD_BwE

I have astrodon filters in the FW.

 

I have used it with the Rokinon 135mm and it worked fine.

 

The photo shows the assembly, with a different Nikon lens. I put electrical tape around the tilt plate so that might look a bit confusing.

If you don't use  fully manual lens you will need a way to hold the aperture iris open. I am thinking to design and print a collar that would do just that.


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#10 andysea

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Posted 06 August 2020 - 11:54 PM

You’ll love it. It’s the most ccd-like cmos camera that I have ever used.
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