Quote:
Originally Posted by JethroB76
...helping to push the uber-fast dob barrow
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Been there with a 12" f/3.7 and I think it was a mistake. Aside from the coma (I didn't have a coma corrector 20 years ago) the secondary was humongous to the point of degrading the image badly, and the eyepieces to match were hopelessly short. I concluded that as a Newtonian f/5 to f/7 was more optimal, with a comfortable secondary obstruction, a flatter field, add some decent eyepieces and NO need for a parracor...
Mirrors under f/3 really only belong in cassegrain or folded newtonian* systems IMHO.
* this kind:
http://web.me.com/wx88/Site/Folded_Newtonian.html
Conversely his scope would be an ideal candidate to convert to a folded newtonian...