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Old 16-09-2017, 03:04 PM
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gregbradley
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Join Date: Feb 2006
Location: Sydney
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I am not totally convinced of these arguments. I have both types of scopes - the AP Honders 305 F3.8 1159mm focal length scope and a Planewave CDK
17inch 432mm aperture scope at 2936mm focal length.

The Honders is better at widefield. It can do galaxies well with small pixels (Sony 694 sensor) but I get a better result from the CDK. I have seen Peter Wards images with similar setups show the same results.

It may be more the aperture rather than the focal length but there is a point where large aperture is hard to physically handle without being in a more compact form like an RC or CDK etc. A 17 inch Newt would be very hard to handle and wind prone as well.

Perhaps its the old adage "aperture rules" at work more than the focal length but the 2 concepts are really intertwined.

Small pixel cameras come with their own baggage as well. Small wells, Sony
CCDs are more prone to fixed pattern noise too.

Greg.
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