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View Full Version here: : Extreme cold killed my guide cam, so I had to resort to this!


jones
21-02-2011, 02:42 AM
Hi,
for those of you who don't know me, I live in Finland. We've had a long streak of cold nights lately, all below -20C. My QHY5 camera and my flat foil have had the worst from it, being now dead.

Still I could not afford to waste a cloud free night! Let's see if you can recognize the constellation I imaged. Here's some specs first:

Un-modded Canon 450D
50mm f/1.8 lens @ f/2.8
90x120" @ ISO400
30 flats and flat darks
9 darks
30 offsets
Processed with Iris and PS

Here's the full field: http://i.imgur.com/ipieY.jpg
And here's a 100% crop: http://i.imgur.com/EwA7j.jpg

I didn't manage to get rid of some more gradients and odd "stains", but all in all I'm glad the night didn't go wasted.

So, who will guess the constellation first? :question:

prokyon
21-02-2011, 02:44 AM
Auriga?

jones
21-02-2011, 02:45 AM
We've got a winner!

bojan
21-02-2011, 06:48 AM
Hey, that's not fair! Northerners should have been excluded from this competition :P

But.. very nice image :thumbsup:
(Just a bit too much of a coma in corners.. maybe the lens should have been stopped down to f/4 or f5.6 ?)

jones
21-02-2011, 07:21 AM
Yes, I think so. That was my first try with that lens. A quick test at f/4 showed a definite improvement. I hope I can post a new image tomorrow :)

jjjnettie
21-02-2011, 08:28 AM
LOL Enjoy your last few months with that constellation.
The menu is going to be changing and you'll be asking us what that constellation is. :lol:

multiweb
21-02-2011, 06:20 PM
I didn't think extreme cold could be bad for CCD imaging or damage equipment. What happened?

jones
21-02-2011, 06:26 PM
For the cam, I believe the culprit was bringing it inside. What happened is that the metal around the USB port shrunk because of the cold, so the USB cable didn't fit it anymore. I brought camera and cable inside for a while to let the metal dilate to regular size again. I suppose the condensation of the air produced droplets of water on the electronics thus damaging them.

For the flats foil, the extremely thin and delicate electric wire running from the power converted to the foil itself was frozen solid, and it broke as soon as I touched it. That should be repairable though.

multiweb
21-02-2011, 06:29 PM
Ha.. got it. Yes extreme cold makes everything brittle. I use to break the socks on the clothlines and get in trouble as a kid. Holes everywhere when they thawed :P

prokyon
22-02-2011, 04:01 AM
Sorry, you are right! :o