Scope comparison

by Richard Navarrete


I set-up Professor Plum (my homemade 8" f/7 newtonian) and my 8" Meade SCT in my backyard last night. Figured I'd do a little shoot out. In short, the Prof kicked the SCT's behind pretty handily. I choose the crater Albategnius (Rukl page 115) There are four small craters plotted inside the crater near the central peak. When the seeing steadied all four were obvious in the Prof. I almost thought I caught two of them with the SCT, but they were fleeting glimpses at best. The central peak itself reminded me of a Hershey's kiss in the SCT. In the Prof it was clear there was some smaller bits associated with the central peak. In the SCT it was one big mush. I had the SCT out for about 3 hours cooling down and checked collimation in both scopes. The Prof needed some work, the SCT did not. Just for the heck of it I took the SCT off of the GM8 mount and brought my TV 101 out. Even without cooling down, the difference in sharpness and contrast from the SCT was obvious. Checked out that crater again at 180x (6mm radian and an old Celestron barlow.) The central peak was sharper than in the SCT, and I saw two of the craters at times, and even had glimpses of all 4. They were still fairly obvious in the Prof. at 175x (8mm Radian)

I've been told by many people that I had a 'good' SCT, but now I'm beginning to wonder. Is it the fact that newtonians and refractors are just a better overall design. The image in the SCT was brighter than the 101 for sure, but the clarity was in another league with the 101. I had the feeling the 101 was sharper than the Prof, but the Prof beat it in resolution.

Love these warm spring nights.