If anyone tries to tell you that it's not worth spending the money on quality optics, just slap them in their silly head.
I finally bit the bullet and bought a parracor II for my F/3.9 astrograph, and the difference in resolution and detail is astounding (not to mention the coma correction of course).
I was shooting one of my favorite targets, Abell 426, with a very tight FWHM filter to get only the best frames I could on a windy night in suburban OKC. After 2-1/2 hours of total exposure (10-second subs), I saw something unexpected. When I zoomed in on a small area, I was able to clearly see two galaxies almost perfectly hidden behind foreground stars.
This is a screen capture directly off the SC window...not even an actual image file.

http://www.jcsautomation.com/temp/hidden_galaxies.png
