cool down

[newarcher]

hi can someone explain to me about cooldown do scopes get warm? sorry if this is a silly question i dont have a scope yet thanks

[Black Knight]

Scopes should be at ambient outside temperature for best performance. If you keep your scope indoors in a warm room, you should allow it to cool down outside for 30 mins or so (depending on the scope) before trying to use it, otherwise warm air currents in the tube will affect the view. If you keep the scope in a shed or garage, you may not need to bother.

[Robb1]

What about when you are finished star gazing is it ok to bring the telescope back into the same room or should it be put somewhere cooler first?

[AWR]

If there is any temperature difference between the scope and the air it is being used in, then the scope will heat up the air around it. This air will then convect (ie. move). Think of the shimmering you see if you look along a runway on a hot day. The temperature difference (and hence amount of shimmering) are much less but you are magnifying this movement.

As said, the amount of cooldown time depends on where you store your scope, and the design of the scope. My small Mak takes twice as long to cool down as my Dob (with its open end).

More expensive scopes may come with fans installed, other people retro-fit their own (braver and more skillful people than me!). Eventually I will get a simple observatory and the scopes will already be at the right temperature.

Andrew

[Kevdan]

When putting the scope away most people who have scopes will turn the scope so its pointing down and leave the end cap off over night so that any dew or misting of the mirrors when bought indoors will run off if it is heavy enough to to forma drip, other wise it will simply evaporate.

Kev.

[Flaxinator]

When leaving a scope to cooldown, what position do u leave it in?

Pointing straight up should allow warm air to rise but with the cap off could allow contamination to fall on to the mirror.

Or

At an angle which would still allow warm air to escape but more slowly and less likelyhood of contamintion entering the tube.

Paul F

[AWR]

What about when you are finished star gazing is it ok to bring the telescope back into the same room or should it be put somewhere cooler first?

Different people use different approaches. This is mine which seems to work:

I cover my scope first and then bring it indoors. I don't remove any covers until the scope has warmed up. The idea is to stop warmer (moister) air from getting to the mirrors and lenses.

HTH,

Andrew

[Black Knight]

I cover my scope first and then bring it indoors. I don't remove any covers until the scope has warmed up. The idea is to stop warmer (moister) air from getting to the mirrors and lenses.

HTH,

Andrew

I do the same. Don't know if it's the right thing to do or not!