focal reducer?

[iamjulian]

Hello, I am looking for advice. My images are about 0.8 arc seconds per pixel, so I am slightly oversampling(?) I have a 200pds scope with a dslr so I wondered whether a focal reducer would help. I was looking at the SkyWatcher coma corrector but some listings suggested a slight reduction, others said no reduction. Any other recommendations welcome. Many thanks.

[Adam J]

21 hours ago, iamjulian said:

Hello, I am looking for advice. My images are about 0.8 arc seconds per pixel, so I am slightly oversampling(?) I have a 200pds scope with a dslr so I wondered whether a focal reducer would help. I was looking at the SkyWatcher coma corrector but some listings suggested a slight reduction, others said no reduction. Any other recommendations welcome. Many thanks.

the SW coma corrector is a 0.9 reducer but there are two models one is optimal for the F5 scope and will reduce by 0.9 and the other for F4 and does not reduce. 

You want this: https://www.firstlightoptics.com/coma-correctors/skywatcher-coma-corrector.html

It will take your focal length from 1000mm to 900mm 

Be aware though that there are some issues with reflections on very bright stars, not an issue 95% of the time but if you want to image the horses head you will get a reflection from Alnitak. Apart from that its good. 

 

[ollypenrice]

We can't ignore the fact that the large F10, giving a higher resolution than the small F5, can have its image resampled downwards to exploit the larger number of photons it captured.