Spot on my mirror :(

[MrTreyLynch]

What are my options folks? I have only had her a week and have kept the caps on so I am pretty confused! It's a 10 inch dob

[Mr Q]

Is it a large spot? Bigger than a half inch? If not, it shouldn't degrade your images to any noticable degree. But any spot can lead to surface damage if left long enough. Best bet is to remove the mirror and clean it in a safe manner, then replace it exactly the same way it was on the tube (orientation) by marking the mirror cell holder and the tube before disassembly.

[Rob Severn]

Could have been caused by condenation dripping from the front cover onto the mirror, my covers are sometimes beaded with moisture after a session and so are dried thoroughly before replacing. As has been said above, try not to worry about it although it is vexing when your new scope is no longer pristine.

[The_PSY3NTIST]

You are not on about the marker in the middle are you??

[ollypenrice]

Can you say more about the spot or send an image? It is easy to be too concerned about such things.

Olly

[NGC 1502]

Most spots/dust are best left alone. Mirrors can look quite grotty and still deliver good views. As post #4 mentions, an image or further description would help.

After a mirror is more than a few weeks old, if you look at it by shining a torch down the tube at night, it will show up a lot of dust that can be safely ignored.

Best to inspect in normal daylight.

Regards, Ed.

[MrTreyLynch]

You are not on about the marker in the middle are you??

Lol no it's towards the side. Could honestly be bat poop! Half the size of a dime!

[cotterless45]

Yep,

you don't want to be continually cleaning your mirror. I had a load of spots of greasy aviation fuel on there for ages, no effect on view. I've seen mirrors with spider webs and enough dust to look filthy. Just wait until you notice it visually.

[Scott]

advise not to clean is sound, although batpoo might be acidic which can't be good for the mirror.

[peeceeTal2M]

If you think it could be bat poo try soaking the mirror in warm water until it softens then rinse off the worst with distilled water and let mirror dry. Any marks that are left will not degrade your views enough to worry about, but this is only my opinion.

[ollypenrice]

Agreed about bat poo. When I was a student a monkey poo-ed on my car (don't ask!!!) and finding this an excellent anecdote (as a student would...) I left it for quite a while. It did indeed corrode the paintwork quite significantly.

Olly