Quote:
Originally Posted by Kirkus
It's almost making more sense to keep my 6" for my attempts at DSOs (a much bigger challenge) and spend my money on an ED100 for use with planetary. Does that sound about right?
|
The 6" reflector will be better than the ED100 for planetary, and for the same points as mentioned in my first reply - bigger aperture, and the reflector has
zero chromattic abberation.
The ED100 will have much improved chromatic abberation compared to the 90mm achromat, but the reduction in chromatic abberation is suitable for visual work, where the eye is less sensitive than any CCD, and low power deep sky astrophotography, where the chromatic abberation that is present will be confined to only a pixel or two because of the short focal length work. To get any image scale for planetary imaging, you will need to run that ED refractor at maybe F40+, and this immediately means that those 1-2 pixels of chromattic abberation become 5-10 pixels, destroying any contrast on the features.
Stick with a reflector type scope for planetary (wether it be a reflector, a schmidt cassegrain, or a makstutov cassegrain), and use the refractor for deep sky astrophotography. If you want an idea of what type of scope is suited to what type of astrophotography spend half an hour in the "images" section of these forums and look at the types of scopes used for planetary and deep sky work respectively.