Polisher

I really don't understand the perception that collimating a Newtonian is difficult. I have been using a 10" f/3.9 for years and I check/adjust collimation prior to EVERY imaging session. I even do it during sessions if the temp changes much. It's done on the mount and I don't even take it out of the tracking mode. What is it that folks think is difficult? Seriously, when it comes to a Newt I don't even consider it. On a refractor, although they rarely need it, collimating is a major project that usually requires removing the telescope from the mount and heading for the "bench". Some years ago I went with a 130mm triplet that I never COULD get perfectly collimated. I finally took it to the Small Optics Lab at Steward Observatory to have it done. Again, once it is done it will probably never need it again. The "big three" for astrophotography is MOUNT, MOUNT, MOUNT. Old saying, "you can compensate for a nominal scope with a good mount but you can NEVER compensate for a bad mount with an excellent optic".