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Old 14-08-2014, 10:45 PM
Tony_ (Tony)
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Location: Melbourne, Australia
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SCT f/6.3 reducer question

Tonight I was going to use my Hirsch f/6.3 reducer for imaging with a c9.25".
I checked my collimation without the reducer and it was pretty much spot on. When I put the reducer on and checked it (with a 60d) the collimation was way out away from the center. The center of the collimation pattern was moved outwards from the center of the image.
I guess this means the image isn't flat at all - possibly over corrected?
Is it because the Hirsch reducer is crap or unsuitable or do I need to use spacers? From what I have read the Hirsch one is similar to the Meade reducer and the Antares is similar to the Celestron brand. Or are they all the same?
Any suggestions? What is the best reducer and set up with a C9.25 (standard). I usually image at f/10 - but that isn't easy.

Regards,
Tony.
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  #2  
Old 10-11-2014, 06:09 PM
Tony_ (Tony)
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After doing some more research - I found more reviews that said the Hirsch is not the same as a Celestron reducer. So I decided to buy a Celestron reducer. Looking at the 2 reducers the optics don't look the same, different coatings and different reflection patterns.
Here is my first image. Grus trio, cds canon 60d @ -14C, ISO1600, 90 x 30 sec exposures. no flats. unguided.
I've still got some issues to work on but I'm happy with it overall. The overall image is much flatter than with the Hirsch. Seeing conditions weren't great but it has potential and f/6.3 seemed easier to get roundish stars than f/10. Even the noise seems reduced. Once I use flats to reduce vignetting and improve guiding I should get a better result.
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  #3  
Old 10-11-2014, 10:39 PM
Tony_ (Tony)
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more gradient removal (photoshop).
A bit noisy - but overall I'm happy with it.
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