Let it cool.

[rmcpb (Rob)]

This week I caused myself a lot of grief when I should have known better.

I was doing some mods to the scope and finished up on Wednesday night with a final collimation. I then put the scope out on the back deck for a while before taking it out for a quick peek to see how the mods worked. Disaster!! Nothing focused, stars were just fuzzy blobs. Decided to leave it as I was a bit frustrated and that is not a good frame of mind to try fixing anything so I just put the scope in its shed so I could have another go the next night.

Thursday and I collimated again, for what felt the hundredth time, no real changes. Stuck my head out to notice some heavy cloud to the west so, as Althair in Aquia was visible I went out to have another go. Instant pinpoint

The point to this rambling post? The only difference between the nights was that the scope was at ambient temperature on Thursday and had not cooled down on Wednesday night. As my scope is usually at ambient I was just a bit lazy on Wednesday and should not have fallen for that trap.

For the best results ensure your scope is at ambient temperature before trying to use it otherwise you will be very disappointed.

Good viewing.

[RB (Andrew)]

Thanks Rob,


That's great advice.

[atalas]

You hit the nail on the head Rob !no truer words have been spoken,and I would just like to add that for the SCT owners out there this acclimatization can take up to two hours sometimes ! so putting your scope out a couple of hours before viewing is a good idea.

Louie

[asimov (John)]

That go's for refractors too. I have better success if it's out for 1.5 hrs before viewing. My 12.5" reflector sometimes takes 4 hrs to reach ambient.

[ving (David)]

yup a cool down time for all scope is a good thing