Condensation??

[tombulgin]

I am a new dob owner (10 inch). Scope was outside for about 4 hours from 3.30pm yesterday (failing to see any eclipse evidence). The outside temp dropped to about 2.0C by 7.30pm and I brought the scope back inside where it is snug and warm (my garden office). The primary mirror was clear when I brought it in, but within 3-5 minutes crazy paving condensation appeared all over my primary. I blow dried it with hair-drier twice and this seemed to have dealt with it.

Is this standard procedure - and the correct way to deal with this issue?

There was no apparent condensation on the scope while it was outside.

Thanks!

Thanks.

[darrenbushnalluk]

Yep, a blast of hot air will do no harm but you could just leave it without its end cap in the house and it will clear in its own time.

[Moonshane]

personally I'd never blow warm air on cold optics.

condensation on optics when you bring your scope in, is normal as far as I'm concerned. I leave mine uncapped and at about 30-45 degree inclination until the morning by which time it's all gone.

then recap until next time. dew/condensation which is allowed to dry will be highly unlikely to damage optical coatings as long as it can dry off fairly quickly. it's only really dangerous when allowed to fester under the cap for longer periods.