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Coma Corrector Comparison

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83 replies to this topic

#76 Andre Moutinho

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Posted 14 June 2020 - 10:18 AM

Hi all,
Any comparison with teh TS maxfield 0.95x?
Thanks

#77 Chad7531

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Posted 16 March 2023 - 08:34 PM

To be honest I find it slightly hard to believe that the MPCC performs as badly as shown here.


It doesn’t. If there were three more steps of better after the skywatcher, it would fall there.

Edited by Chad7531, 16 March 2023 - 08:34 PM.


#78 mrkhagol

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Posted 27 January 2025 - 11:53 PM

So I've had not much luck with MPCC and thinking about skywatcher CC-but my reflector is at f/5, would skywatcher CC work fine or that would not get the desired result?


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#79 Starman1

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Posted 28 January 2025 - 01:43 AM

So I've had not much luck with MPCC and thinking about skywatcher CC-but my reflector is at f/5, would skywatcher CC work fine or that would not get the desired result?

All the commercial drop-in coma correctors will work fine at f/5.

Not all will come to focus in every newtonian scope, however.


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#80 mazdak

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Posted 04 February 2025 - 01:20 AM

So I've had not much luck with MPCC and thinking about skywatcher CC-but my reflector is at f/5, would skywatcher CC work fine or that would not get the desired result?

Before changing to SW coma corrector I recommend to stop down the aperture a little ( 200mm to 170mm).

this will convert f5 to f6 and you have 3 positive things.

1. Any possible TDE will be removed.

2. illuminated field increases.

3. higher order of correction you have


Edited by mazdak, 04 February 2025 - 05:48 AM.


#81 mayhem13

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Posted 04 February 2025 - 06:35 AM

So I've had not much luck with MPCC and thinking about skywatcher CC-but my reflector is at f/5, would skywatcher CC work fine or that would not get the desired result?

Depends……you didn’t mention what issue you’re having the the MPCC. If it won’t come to focus it’s because your focuser doesn’t have enough inward travel to reach the focal point with the glass in the MPCC. 
 

But if the issue is just you still have coma, that’s the most common reported issue with the MPCC. This often comes from folks looking to use a larger APS C sensor……then it’s no longer a matter of quality but quantity……you need a 3” optical path for that.


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#82 CrazyPanda

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Posted Yesterday, 12:38 AM

2. illuminated field increases.

 

The illuminated field doesn't really increase. It just appears more even. By stopping down the aperture you've sacrificed brightness in the middle, and the edges may see more of a "whole" objective, but that "whole" objective is smaller, therefore less light anyway. So the edges don't really get better, it's just the fully illuminated field gets darker and therefore everything looks more uniform.


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#83 mrkhagol

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Posted Yesterday, 06:08 PM

Depends……you didn’t mention what issue you’re having the the MPCC. If it won’t come to focus it’s because your focuser doesn’t have enough inward travel to reach the focal point with the glass in the MPCC. 
 

But if the issue is just you still have coma, that’s the most common reported issue with the MPCC. This often comes from folks looking to use a larger APS C sensor……then it’s no longer a matter of quality but quantity……you need a 3” optical path for that.

ok now you've pointed out something i wasn't quite aware of-3" optical path - guess that more than explains it.

 

focusing is not an issue though with inward travel..



#84 mrkhagol

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Posted Yesterday, 06:09 PM

Before changing to SW coma corrector I recommend to stop down the aperture a little ( 200mm to 170mm).

this will convert f5 to f6 and you have 3 positive things.

1. Any possible TDE will be removed.

2. illuminated field increases.

3. higher order of correction you have

yes this is one possible option- i've kind of done it before but not a big fan of it. it under utilizes my scope in that regards.




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