Posted: Jun 15, 2020 4:00 am
by theropod_V_2.0
Hmm, EQ mounts, to me, are a breeze. My simple little iOptron SkyTracker Pro with a modest polar scope can keep Jupiter in the FOV all night long with the 32mm EP in the C-90 Mak. I’ve watched moon shadow transits with just that setup. All I need do is spend about 5 minutes really getting Polaris on the gradient circle position as indicated by an app iOptron released. It takes my GPS data and puts Polaris as a green dot along a clockface of the setting circle. Match that in the little alignment scope with the adjusters, slowly lock it down, and readjust as torque is applied, and you’re good. Keep in mind this is a cheap little photo tracker, and my little C-90 is at its max load. Besides, everyone should learn how to drift align an EQ mount since Polaris might not be viewable from your location. A mountain might get in the way.

What I have against Newtonian scopes is the open end of the OTA exposing the mirror to mother nature, the spiders for the secondary mirror and collimating the damned things. Granted, modern mirror surfaces are/can be much better than a decade ago, but dust and gunk gets on it eventually. Just cleaning the primary mirror is a bitch. The spiders impart a spike distortion unless arched absolutely perfectly, and then still be robust enough to carry the secondary mirror without moving. Some Newtonian scopes require collimating with each move of any significance, and can be a frustrating bitch to do in the field. We won’t go into astigmatisms, frame distortions or the myriad of issues that a cheap Newtonian could present.

Yes, CAT scopes have issues. A narrow FOV, long cool down time that increases with size and secondary mirror obstruction. The up side is that a modern CAT scope made by any of the big 3 will probably never have to be collimated unless disassembled for deep cleaning. The focus on these scopes is usually butter smooth, but doesn’t drift. Mine is a dream. CATs take up less space when traveling, and even a 10” Mak could fit in an overhead compartment.

Yes, we are talking about a pretty serious investment here, and a Newtonian does win the coins battle. Then again more Fords are sold than Rolls Royces. If I were getting a scope on a whim the Newt wins hands down. If I’m ready to do some work, like study the dust lanes of Andromeda, give me a CAT.