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Newtonian and focal reducer


R26 oldtimer

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Hello everyone!

I have a sw 130p f/5 that I use for eaa with a diy Effio-a camera (same as revolution imager2). I was thinking of getting a 0.5 reducer to use with that setup in order to speed things up to f/2.5 but was wondering if the focal reducer will induce any annoying ca. What do you think?

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1 hour ago, shirva said:

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

Haven't got one but had seen this for sale from FLO

How would a coma corrector or otherwise focal reducer affect focus position? Normally barlows will push focus outwards and reducers pull focus further in. So unless the reducer is designed not to do that it might cause issues achieving prime focus for some scopes?

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53 minutes ago, pipnina said:

How would a coma corrector or otherwise focal reducer affect focus position? Normally barlows will push focus outwards and reducers pull focus further in. So unless the reducer is designed not to do that it might cause issues achieving prime focus for some scopes?

As in my reply I haven't got one,, but I take it skywatcher make them for a reason and FLO sell them,,, there is a description on Flo's link

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  • 3 weeks later...

I have just found this thread as I am doing some research on the exact same thing. Having just purchased an ASI224MC and 0.5x reducer, I have a 130PDS and a 200p that I am looking to do this with.
From what little research I have done so far it seems to be that smaller chipped sensors do not suffer so much with issues such as coma etc... to the same degree that a larger sized sensor would.
The other interesting thing to note is that a 0.5x reducer can be used as a 0.6x or 0.7x etc... depending on the distance from the sensor, this should allow for better tuning.
As far as using the SW Coma corrector, this I cannot comment on. The issue you may have here is that the SW CC already has a focal reducer built in.
If Coma is a problem then I have the Baader MPCC Corrector that I can test this with and may be a better option (although only rated down to f/4).

I will be following this with interest

 

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