Thread: Mount Upgrade
View Single Post
Old 31-03-2019, 08:42 AM
lazjen's Avatar
lazjen (Chris)
PI cult member

lazjen is offline
Join Date: Dec 2012
Location: Flaxton, Qld
Posts: 2,032
Originally Posted by gregbradley View Post
The real test of any mount is can you get round stars at 10minute exposures at a decent focal length. If you can its a winner.

Other things help but are not essential. That's the guts of it.

Also with a good mount round stars are not guaranteed. A good PEC and accurate polar alignment are pretty important. I use Sky X Tpoint for getting perfect polar alignment. Its an amazing tool and you see the results immediately in the very low autoguiding errors.
If I have all the necessary base plate bits here right now, I'm going to start with the refractor at 700mm (F6.54) - I think I'll need to change it from the narrow V to the wider D as it looks like the CEM120 accepts the wider plate only. I'll look into this soon. EDIT: Well that was easy - got a base plate adapter that I can use so I can mount the refractor in the same way as if it was on top the RC10.

At some point though I will be using the RC10 at either 2000mm (F8) or with the reducer at 1340mm (F5.36) to go further. I'd like to jump to this straight away but I suspect I may need to recollimate it first. Don't want to deal with that right now if I can avoid it.

There's no PEC on the encoder versions of the CEM120 (i.e. the CEM120EC and CEM120EC2), therefore I won't need to worry about that. (Manual, pg 31:

The manual lists some supplied alignment options (pg 26). I might try some out for the sake of reviewing to see how they go. Won't be a completely fair or proper test though as I will have this installed in the dome permanently so I expect that each test is likely to refine the last result. Eventually though I will try/review those results with tools I've got and then refine further if required.
Reply With Quote