Bad Collimation? C9.25 XLT

no there is just the focuser knob/wheel.

theoretically i get into focus. i can get over the focus in both directions. but the picture "in focus" is still awful and like doubled at the tree edges.

There is only one true way to adjust you mirrors and that’s with a star. Owning an SCT for over 40 years 8” 12” and a C6” I’ve had every conceivable way to culminate my scope and the only way to get true culmination is to use a star. I use Polaris to do both of mine. Polaris hardly moves any so it give you time to tweak it then recenter your scope. Also when you are doing this try to keep whatever star you use in the center of the field of view it matters. Also there is a tri-batanov mask for those of us who use SCT’s. It is not only used for focus but gives you 6 alignment points that aid in culminating the SCT. There are numerous videos on YouTube that can assist you in using one. I highly recommend you getting one of these. Also try to put your camera if that is what you are using directly on the back of the scope no extenders, no focuser, nothing. Backfocus has no bearing on this adjustment. Backfocus is only for reducers and correctors which you never want in the optical train while you’re doing this adjustment. There are a couple of culmination tools for your laptop if you image on that. One for a Mac and one for windows that put an adjustable set on circles on your screen that you align your star to, that can help if you aren’t using the tri_-batanov mask. Give those two methods a try and if you still can’t achieve good culmination you’ll need to have your scope checked out for other problems. And the main mirror on the Celestron and Meade SCT’s do move to adjust focus.  So there can be issues there with mirror shift and tilt. Heard about them, never experienced it myself. I have both. Truly my suggestion is to ditch the laser, been there done that, and the artificial star and just use the real thing. Works every time. And take your time. Again if after you get your adjustment and are still have focus issues you have other problems that will need the expertise of a trained professional to sort out.

i tried a tree 2 miles away… same crap. so i know its not the distance. there is something seriously wrong. i will try it at a star tomorrow. but i allready know it will be not good.

tom gray you say i should not tighten the collimation screws to much. i tighten them very well, i should loose them a bit, maybe it helps.
allready got bobs knobs thx :-)
 
hey toni, i have a tri bathinov. will try it tomorrow. thx for your advises.

i think i have a main mirror tilt/problem. or how it is possible to see thin branches and an artificial star two times shiftet? :-(

thx eddie i will try tonight. hope thats the problem. thx alot guys, i will give feedback