Collimation of newtonian (Skywatcher 200p)

[Pete Presland]

laser or cheshire, the ultimate test is the star test!

[malc-c]

Why are collimation tools not handed out with the scope on purchase - if the process is so important for getting a good experience with the scope?! Slightly annoying..

Same way as a car dealer won't supply the specialist servicing tools when you buy a new car

I opted for a Hotec laser collimator due to the self-centering fitting, and it's a doddle to use. Yes, they are expensive at over £100 new, but occasionally they come up on the second-hand market.

I tend to check collimation on a monthly basis as it's one of those things you can do anytime of the day.

[Jason D]

laser or cheshire, the ultimate test is the star test!

I would not use the word "ultimate"

Star collimation tells very little about how well your secondary mirror is adjusted. It does tell you though how good your primary mirror is aligned. Interestingly, a quality collimation tool can produce more accurate primary alignment than what you could get with star collimation.

Jason

[Jason D]

Thanks for the responses so far - great stuff...

Have had a quick read of the Astro-Baby site and picked out this bit:

"Note: Some scopes require the secondary mirror to be offset from the centre of the tube. This in itself raises questions. Some telescopes will have the secondary offset on its holder in which case the centre of the vanes should be centred to the tube while other manufacturers will opt for the vanes centre point being off centre. The offset on most scopes will be in millimetres and wont affect collimation by much. You should check whether your telescope requires offsetting with the manufacturer or supplier. If you cannot get an answer assume that the mirror holder is to be central to the telescope tube."

So, anybody know how this applies to the SkyWatcher 200p (BD model). ?

Offsetting the secondary mirror away from the focuser can help improving the DSC accuracy -- my a little amount. It also might be needed to avoid vignetting for scopes with tight opening. But it really does nothing to improve collimation.

Jason

[coxy322]

Cheshire finally ordered from FLO ... Looking forward to my first ever attempt at collimation v. soon!

[derekbcox]

chesire it is then !

[derekbcox]

then you can come and do mine .