View Full Version : Cleaning a Newtonian Primary

2003-Mar-26, 04:23 PM
The primary mirror on my Orion XT10 has gotten kind of smudgy. What is the best way to clean it? Is there some sort of cloth and non-abrasive cleanser combo I could use? This is one of the older model XT10's that does not have the Pyrex primary (figures that I splurge on a decent scope, and the next year's model features a better primary AND a lower price!).

David Hall
2003-Mar-26, 04:55 PM
We had a previous discussion about it here:


Short answer is, never use any kind of abrasive or scrubbing action. The coatings are much too delicate for that.

2003-Mar-26, 05:15 PM
Thanks. I always forget to search before I ask!!!
It sounds like the methods mentioned in that post should work. The dust cap got knocked off my tube and some unidentified schpilkis settled on my primary.

2003-Mar-26, 05:46 PM
The last time I had my primary out, I gently brushed off the dust with the brush side of my lens pen (found in camera shops).

Also, I had crud on the eyepieces. The lens pen tip was too wide to access them, so I just took them apart.

I had trouble getting the 4mm out so it has a few small scratches now. I don't really care. I never liked it. I would have been upset if that happened to the other jewelry!