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Old 12-06-2010, 05:54 AM
astrospotter (Mark)
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Join Date: Jan 2010
Location: San Jose, CA, USA
Posts: 146
How evil is an f/6.3 reducer?

This is a re-post I had on begining astrophotography which may be better in this area as it may be just above a beginner topic perhaps.

I have a williams optics FLT110 f/6.5 APO with the WO 0.8 field flattener. This is collecting photons into a Canon 40d and does this job as well as can be expected. Now I seek broader field of view with same scope.

What sort of evil things will happen to the image if I try to use a Celestron f/6.3 focal reducer between the 40D and the field flattener?

I would expect the image gets warped to some extent but if I don't stitch mosaics is it not warped so badly as to still generate fair results for single frame sized shots?

Does the the reducer re-introduce gobs of chromatic garbage in the corners?

Do the corners become un-usable due to focus?

Does it 'just work' and I am over-analyzing this? (doubt this is the case).

Now if you don't think I am insane just yet, how about the same trick with a Meade f/3.3 focal reducer (it is ok to laugh, I can take it).

Thanks for any knowledgeable replies from anybody who has actually tried this OR knows the direct results of someone who has actually tried this. I know the image will suffer, just don't have a feel for how much yet.

Thanks,
Mark
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