Imaging in cold weather.

[ryandsimmons]

The weather is currently balmy and lovely here, but a question popped into my mind a few minutes ago that is bugging me.

In the middle of winter when the ground is icy and the skies are clear is it okay to still sit outside imaging?  A few considerations come to mind:

1) Would severely cold temperatures damage the optics or the GOTO system? (I am in the UK so not too severe, but coming from South Africa anything below freezing is insane for me.)

2) Do you need to worry about mirrors cracking etc, due to fast cool downs?

3) Does dew control become a major issue?

4) Do power packs suffer?

For reference I have a Clestron C8 on a CG5 GOTO if that makes any difference.

[ChrisLX200]

1) No - optics will be fine. I have heard of cemented lenses coming apart moving from extremely low temps (like, -40c) to indoors.

2) No - as above.

3) Yes, preventing dew and frost forming on lenses and mirrors requires the use of dew heaters. I've had frost on the secondary of my Newt before now.

4) Yes, low temperatures mean the battery will not output its full rated capacity. It will not freeze though.

ChrisH

[Alien 13]

As ChrisH above the one big bonus of the cold with DSLRs anyway is the reduced camera noise.

Alan

[StuartJPP]

Further to above, to me anyway, dew is the biggest problem and dew heaters become necessary, almost mandatory in my limited experience. Dew shields are okay for a limited period. Batteries can be placed into something to help insulate them.

Bringing equipment back indoors is a pain as it will dew over instantly, I have got a large zip lock bag that I place my optics in along with a disposable (PoundLand) dehumidifier. As soon as it reaches equilibrium with the indoor temperature I remove it from the bag...though this can take an hour or more.

In the depths of winter I have had frost form on my lens barrels, camera and mount and even battery pack but not the optics due to the dew heaters doing their job.

[Owmuchonomy]

As the guys say above plus I'm going to try and reduce the winter effect by building an Obsy this year.

[laser_jock99]

As ChrisH above the one big bonus of the cold with DSLRs anyway is the reduced camera noise.

Alan

I have noticed lower noise on DSLR images in the depths of winter- and some noisy images summer 2013 when the overnight temp didn't get much lower than 20 deg C.

On the whole though I'd say imaging in lower temperatures is fine at least for the equipment. In 2011 I think we had overnight lows of -22 deg or so and I don't remember any problems with the scopes other than it being too cold to stay outside like I normally do! 

I find imaging in dewy conditions far worse.

[ryandsimmons]

Cheers guys.  As always very helpful.