Collimation Gotcha

[Sam]

I've never been very happy with the collimation of both my 16" Lightbridge and my 8" reflecter. For the Lightbridge I was wondering if it was some slightly less than ideal optical quality that comes with a big cheap mirror and for the 8" it just had me a little perplexed.

Well I figured out what the problem is! The little round sticker they (the telescope makers) put in the middle of primary mirrors are not actually put in the middle! so if you concentrate on lining up everything else except the little round sticker then the collimation should be pretty good.

I found on the 16" the sticker was quite a way off and on the 8" it was a bit closer but still not in the centre. It made a huge difference as now I can split the Double Double in Lyra with the 15mm eyepiece on the Lightbridge and with the 9mm eyepiece the gap is very pronounced - whereas the last time I checked it could only be split properly with the 5mm eyepiece.

So in summary do not trust that the little sticker is in the exact middle of the primary mirror.

Sam

[daz]

Do you think they throw them on from a distance Sam??

Must admit, not checked mine on the 12", but will be doing so!!

[Sam]

Daz,

I think they look through one eye, angle their head to one side and say "yeah, that looks about right" and plonk the sticker on. Though I think with my Lightbridge they did the throw from a distance thing, a bit like the horseshoe game.

Sam

[Roy]

My mirror didn't have the dot on, I had to apply it myself but the mirror did have a small cross hair etched on the mirror as a guide but actually putting the little circle on was a bit scarry to say the least.