primary mirror

[geoff1962]

just taken the cap off the top of my scope and there is a small amount of dust on the primary mirror im looking for suggestions to remove it,im using a 200p skywatcher,kept inside the house most of the time with cover on, cover only comes off when outside for stargazing any advice welcome:(

[BAZ Senior]

The short answer is don't worry. You will be able to see dust on it, but this does not affect performance. Unless there is something growing in the muck, then leave it. It is very easy to cause irreparable damage to the mirrors if you are not careful.

I have done it to mine and I won't be doing it again in a hurry as the mirror looked cleaner, but it did not improve the performance that my eyes could see anyway.. You need to be able to collimate it again, and if need be as with mine, also move the secondary mirror to get the collimation right.

[Adamski]

I have the same problem and was advised under no circumstances do i try and clean it or blow it off, some dust is acceptable and will not interfere with your viewing. I saw a program the other day in which professional astronomers were setting up their gear and one of the 5 reflectors had cats paw prints all over the mirror but they just left it as it was.

[Lux1]

I agree entirely with the above comments. Don't bother to attempt to clean any of the mirrors in a reflector. However, in many years time,if they are really bad you can soak in warm soapy water and wash off with distilled water.

However, it is best not to bother,- my first telescope, a 3" reflector had a dirty primary mirror, - first thing I did was to pull it out, wash, dry and polish with a duster.

Before,- a slightly dusty mirror.

After, - a dust free mirror covered in fine scratches!

[Moonshane]

best bet is look down the tube and see the dust - adjust the angle slightly and it disappears! ignore it and enjoy observing with no ill effects.

[terrym2002uk]

I've just come across this thread, searching for dusty mirror performance.

I know when I look down my ota, I can see a fine layer of dust and a few cat hairs (dont they get everywhere), but luckly no paw prints!.

I guess unless you have had the chance to peer down other tubes, then the dust looks like a really bad thing to have.

Yes I will be leaving mine well alone. The day I cant see my face in it then I may take it out and clean it, which hopefully will be a long time yet.

[sbooder]

Do not bother removing dust from your mirror, all mirrors will have some dust. It will not diminish your view at all.