Quote:
Originally Posted by Peter Ward
I'd come to the same conclusion some time ago: very few systems are designed to fully cover the field of a KAF16803.
Bottom right of the image above is not great....though I must say closer on axis the result is very impressive.
The only scope I have used that goes the distance, then some is the AP155 + 4" field flattner...no surprises there as it was originally designed to handle 6x7 cm film.
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Quote:
Originally Posted by gregbradley
I can't believe ASA allowed that image to be posted. I commented on it at the time when someone said it was lacking collimation that in fact it was tilt having seen it myself before. That bodes very poorly for the scope that flexure is there even in the prototype.
The 16803 is challenging. AP, TEC, Tak BRC, FSQ106ED, Planewave have measured up so far. I agree TEC and AP measure up the best though.
Lots of excellent images from Bob Fera and his Officina Stellare 14 inch RC and Apogee U16M (16803 chip) show they also can do the job.
Greg.
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I think it is a failure of stacking in that corner during processing in both the individual colours and colour combination. It could be due to a hot pixel/s. Look carefully and the brighter stars have two radial diffraction spikes and the stars show tangential CA in a reflector! Impossible! If anything CA would be radial due to the corrector not being orthogonal to optic axis.
See the upsized crops of the bottom right hand corner below.
Bert