Why use a cooled camera? (Nature does it for free)

[wimvb]

An unexpected clear night, here north of Stockholm. The second in a row, actually. Normally I have my camera at -10 C, but that won't do now. When I just finished a session (don't want to leave my observatory open since I can't trust the forecast), the temperature had dropped to -17.8 C. I have my cooling set to -20. Now I just need to take matching darks for the rest of the night.

I started imaging just after 7 pm, and managed to get 40 minutes H-alpha (wasted) and 4.5 hours RGB on my target.

[gorann]

On a night like that a good DSLR would probably be as good as a cooled astro camera. But other things in the rig may struggle. I rather have a bit warmer nights🤐

[ollypenrice]

2 hours ago, gorann said:

On a night like that a good DSLR would probably be as good as a cooled astro camera. But other things in the rig may struggle. I rather have a bit warmer nights🤐

It might very well simply stop working, though. A guest here made a cool box for his DSLR and killed it! I'm pretty sure he would have been nowhere near -20C either.

In the last 8 years, very cold nights here have simply stopped happening, as has significant snowfall. We'd routinely see -12C and sometimes -19C. Nowadays -6C counts as cold.

Olly

[Mandy D]

20 minutes ago, ollypenrice said:

It might very well simply stop working, though. A guest here made a cool box for his DSLR and killed it! I'm pretty sure he would have been nowhere near -20C either.

In the last 8 years, very cold nights here have simply stopped happening, as has significant snowfall. We'd routinely see -12C and sometimes -19C. Nowadays -6C counts as cold.

Olly

For the Nikon D800, I've seen claims on line of it being used at -38 °C! There are many people using them in temperatures of -30 °C with no problems. I've used my D3200 at -24 °C. Nikon give an operating temperature range of 0 °C to 40 °C, but I think that is to cover themselves. It is wholly impractical to expect that cameras will not be used in freezing conditions. A point which is raised regards the LCD potentially failing at low temperatures, which makes a lot of sense. The other thing that is mentioned is condensation due to changes in temperature. Now, that is where I would expect damage to occur. I'm not sure that I would deliberately cool my DSLRs, but I don't go nuts protecting them from the cold. If it is not too cold for me, then it is OK for my cameras is my philosophy.

[tomato]

I would agree with the moisture comment. My ASI 178 cameras with retro fitted external coolers get condensation dripping off the adapters several centimetres away from the cooler but with the astro cameras with internal coolers the adapters stay dry. 
 

I shudder (appropriate word) to think how my vast array of cables up to the scopes would behave at -20.

[wimvb]

Using any dslr with a mechanical shutter or mirror at such low temperature is a gamble. Otoh, modern non cooled astro cameras with their low dark current and no amp glow are a different matter. As I said in another thread on this forum, my next astrocamera may very well be such a camera, OSC with smaller pixels, used in superpixel mode. (2.9 um in superpixel mode would be 5.8 um effective pixel size. At 1000 mm focal length, this would give a very nice pixel scale.)

[wimvb]

37 minutes ago, tomato said:

I shudder (appropriate word) to think how my vast array of cables up to the scopes would behave at -20.

The simple solution to that is a Raspberry Pi and a Pegasus Astro power box. A friend has his remote controlled setup 1.5 m from mine in the same observatory. Last summer he upgraded his computer and chose a pc next to the pier in stead of a fanless Mele on top of his scope. (Yesterday his cables were like rods). To quote Julia Roberts: ”Big mistake. Big.”

Edited December 6, 2023 by wimvb

[tomato]

Good point, but I can’t see a -20 C night happening any time soon in semi rural Shropshire, too many warm moist fronts coming in from the West.

[wimvb]

It doesn’t happen often here either. At least not this early in the season. February is the coldest month of the year. Yesterday the trees where completely covered with frost. 

[900SL]

I've been toying with the idea of a 533MM uncooled as my imaging season is typically 0C to -20C here.

I'd like solid data on the delta T for 5 minute subs over an hour or so, to see the time - temperature curve. The performance is supposedly very good on amp glow and dark current