How do I check the alignment of my mirrors?

[Peter Reader]

Hi all!

I've had my SKywatcher Explorer 200P for one and a half years now and I'm wondering if I need to collimate my mirrors. I've yet to "unfocus" on a bright star and observe the diffraction pattern, but if it turns out I do need to collimate my scope: what do I need?

Thanks

Pete

[Merlin66]

There are numerous "collimation" threads you should look at...

You'll need as a minimum a collicap ( a suitable eyepiece sized cap with a central 1.5 to 2mm hole), or a Cheshire collimating eyepiece or maybe (but try the others first) a laser collimator.

HTH

[twotter]

I use one of these...

Astro Engineering AC656 Colli-Mate Deluxe eyepiece for collimating Newtonian and other telescopes

...and followed the advice in this video...

Collimating a Newtonian

I'd had my 200P dob for about 18 months too before a quick star test one night showed it needed collimating. After watching the video a few times it took me 15 minutes and turned out my primary mirror needed a minor tweak.

I should say that there are other collimating tools and how-to guides available, but these are what I use.