Re-spotting a primary

[dharma66]

I've been looking at the catseye website, and was wondering if anyone has re-spotted their primary to make use of a different centre spot?

Removing the existing spot sounds really scary to me...

[Moonshane]

you can remove the existing spot but there's no need to other than for aesthetics. the area in which the spot sits is in the shadow of the secondary. just apply to new one over the old. I did this with my 16" mirror which had a spot that was a couple of mm out of centre.

[dharma66]

Thanks moonshane.

I have to say, though, that judging from your sig, it pains me to be receiving so much good advice from the dark side of Manchester

[Moonshane]

ha ha - sky blue is surely the light side of Manchester?

just found my thread see the post half way down this page

[Catanonia]

Yes I did this recently with Cats Eye on my 8 inch primary.

Care is al you need. I got some Acetone and a cotton bud and dabbed the old ring doghnut to loosen it. Then used a toothpick carefuly to prise it up and removed it. Then more Acetone to clean the area before applying the new target.

Remember that this part of the mirror (centre) is actually in the shadow of the secondary to if you mark the mirror, it isn't the end of the world. But be careful.

The Cats Eye system come with a nice target placement sheet to get it bang on the centre.

I would recommend removing the old ring as if you are using the Cats Eye radiation ring, it will not work with the old ring in place.

Good luck

[michael.h.f.wilkinson]

Interesting. the 4.5" mirror of the kiddies mini-Dob has no centre spot. The Catseye procedure seems handy for giving it one.