Quote:
Originally Posted by gregbradley
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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To cover most deep sky objects and coupled with the right two cameras, I recon you have the perfect combination of scopes there really Greg
but aaaand hey, I could be wrong
...I'm gathering Andy is also not in the position to acquire a 17"CDK
and a 12" AP Honders with the two mounts and cameras required either...?
At the end of the day, people like Andy need to do the image comparisons for themselves and do them properly ie compare full res versions, allow for image display size, use of AO, type of camera/pixels used and site quality etc. and critically judge the level of difference and be able to differentiate whether these differences are
perceived or indeed real and
then do what they wish with the budget they have. After already doing this though, I know what I recon
Mike