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Skywatcher 190mn vignetting and correction on large sensors?

Astrophotography Maksutov
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#1 GTom

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Posted 01 October 2023 - 06:06 PM

I am thinking about picking up a Skywatcher 190mn as an "APO alternative" for my APS-H camera (Moravian g3, sensor diameter: 35mm).

I was wondering, has anyone measured the vignetting with a larger, e.g. full frame sensor?

 

Is the tube material strong enough to support a heavy camera as the Moravian without flexure? (AFAIK I'll need to replace the focuser, OTA wall remains a question...)



#2 Spaceman 56

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Posted 02 October 2023 - 02:30 AM

AFAIK I'll need to replace the focuser,

I may be wrong but I read that changing/swapping out  the focuser, has been a recipe for disaster, for some owners of these scopes.

 

can experts confirm or deny this ?


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#3 luxo II

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Posted 02 October 2023 - 03:57 AM

How it will fare with that camera on it… even as is you could try it and see. If you think you can correct the vignetting then yes replace the focuser.

From looking at the size and weight of that camera I’d say yes the stock focuser will be inadequate, for any real imaging use with that camera.

Edited by luxo II, 02 October 2023 - 04:04 AM.

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#4 tocster

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Posted 02 October 2023 - 09:56 AM

I may be wrong but I read that changing/swapping out  the focuser, has been a recipe for disaster, for some owners of these scopes.

 

can experts confirm or deny this ?

The early moonlite focusers were problematic, but I believe a subsequent redesign resolved issues.  I have a moonlite on mine and havent had any problems.


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#5 luxo II

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Posted 02 October 2023 - 03:32 PM

You might see if this fits 

https://www.teleskop...up-to-5-kg.html

 

This is the one I fitted to my MN65, as the base holes matched and provide adjustment, it has a R&P (no slipping with a heavy load) and the compression ring unscrews to expose a 54mm thread so everything screws on securely. TS have curved based plates if you need one, as well.


Edited by luxo II, 02 October 2023 - 03:33 PM.

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#6 GTom

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Posted 03 October 2023 - 06:57 AM

You might see if this fits 

https://www.teleskop...up-to-5-kg.html

 

This is the one I fitted to my MN65, as the base holes matched and provide adjustment, it has a R&P (no slipping with a heavy load) and the compression ring unscrews to expose a 54mm thread so everything screws on securely. TS have curved based plates if you need one, as well.

I think I should go with a 2.5" focuser to avoid vignetting from the drawtube. Will do some raytracing to figure...




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