Cool down...

[Patbloke]

Hi Team,

Ok, so many threads start with 'this might seem a daft question but'?

I think this really might seem a daft one (two actually) -

What happens if you don't cool down your scope for 30 mins (especially on a cold night like tonight)... and can you ever really expect to get any good views from inside your house looking out through an open window?

[Chris H]

If you don't cool your scope it's not going to be the end of the world planetary views won't be as good but lower power views of DSO's will still be pretty good and whilst your using the scope it will be cooling.

I have often used my little 130p for an cheeky glimpse through the window and it was not too bad at all the view was a bit restricted but it was ok.

[nightfisher]

you let scope cool down to remove thermal currants that might distort the image, same applies to viewing through a window as heat is escaping from the room

[John]

It will be fine just don't expect to see the fine detail and crisp images. It can be OK for a quick look at star clusters at low power or a quick peek at the moon.

[Patbloke]

Thanks,

The view of Jupiter was not as clear as it has been before tonight, the image was a little blurred.. I started to panic thinking that my mirror had been contaminated when I bought my scope in from the cold the other night and I got some condensation on the outside of the tube...

So much to learn it's a shame I have to work coz I'm lovin it

[umadog]

A warm mirror creates a "boundary layer" of convective cells which hug its surface. These cells are in constant motion and, due to the different densities of warmer and colder air, refract both the incoming and outgoing light. This refraction blurs the image and the motion of the cells causes the image to look like it's "boiling." Once the mirror has cooled, the problem goes away. These tube currents generally lead to a slow "boiling" whereas poor seeing leads to a fast "boiling."

[Patbloke]

Umadog!

Now that's a genius post... Thank you