Quote:
Originally Posted by Robbie
G,day,
Im new to all this but learning fast, my question is on the use of a 10"meade sct coupled to a meade f/3.3 focal reducer.
when I use the focal reducer , stars start to smudge as they get closer to the edge, Its not too bad ,just enough to annoy me, Ive heared about taking "flat field" shots to correct, but no one has been able to explain them to me as yet.
The shot below is of the cluster M28 taken with a meade 10"sct @f/3.3, orion starshoot dsi2. unguided stack of 12, 40sec exp.
Its the first half decent shot Ive take since "mastering" alignment/drift alignment so try not to laugh too loud.
Many thanks in advance for any helpfull advice and many thanks to Chris James's atricals for getting me this far.
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Flat fielding wont help this problem. A flat will correct variations in light across the field caused by vignettiing or dust on the camera. What you have is an optical aberation from the focal reducer- probably "coma" and this needs an optical solution not a flat field.