Jump to content

DSLR temperature findings


swag72

Recommended Posts

After a couple of nights of looking at the temerature of subs taken with my DSLR I thought I would share the following just in case anyone has any interest in it!

Last night I imaged between 23.49 and 03.37 using my modded 1000D. I was using an Astronomik clip in filter and a power battery from Astronomiser. My subs were 420s at 800 ISO. I reckon the ambient temperature was probably about 25 degrees. I now leave 2 minutes in between subs.

I have looked at the temperatures of 20 subs that I kept between this imaging time. The subs started off at 27 degrees and finished at 26 degrees. There was no huge increase in temperature as the imaging run carried on. The noise at 26-27 degrees is considerable, granted. But all I need to do now is take some darks in the day at 26-27 degrees and that should help that issue.

I have recently got the bits together for a 'cooling system' of a sandwich cooler and some ice packs, thanks to AndyUK and Jsigone on SGL (:BangHead:) I used it 2 nights ago for the first time, and while things with that were a little different (15 min subs for example) I still looked at the temperatures from the start to finish of the imaging run - A lot less images of course but the same amount of time - The temperatures recorded were a constant 17 degrees (Again ambient was probably about 25 degrees).

So what was the point of this post? Well I am surprised that stuff isn't hotter and doesn't get much hotter as the run continues. Unscientifically I also have been able to show that a simple 'cooling system' for DSLR's costing less that £20 will lower the sub temps by approx 10 degrees in my initially use.

Link to comment
Share on other sites

What I've seen with my modded 20D is that subs develop a more pronounced red component after the first one or two subs. I only take 2 minutes subs, not 7 like you and I haven't been allowing any cool-down time between them.

My interpretation of the added redness is that it was due to the sensor warming up.

Link to comment
Share on other sites

I suppose why I posted this, and maybe I need to be more 'scientific' (!) is that I was srongly of the opinion that during an imaging run, the temperature of the subs would be steadily increasing throughout. I am surprised that there was only a +/- 1 degree in temperature.

I assume that the temperatures of the subs responds to the sensor temperature? Perhaps as you don't leave a gap in subs, you may have a rising temperature. I personally do not see an increase in redness.

Link to comment
Share on other sites

I was srongly of the opinion that during an imaging run, the temperature of the subs would be steadily increasing throughout.

Gary Honis has done some work in this area, too. Have a look at his results as it appears that your camera doesn't warm up very much as time goes on.

Link to comment
Share on other sites

Hmmm... I've always found that subs with my 40D have crept up from ambient temp but then levelled out at a temp about 10C higher than ambient. Admittedly, I've only leaving 60s between 10min subs, but I even got this effect when taking some stock darks in the fridge.

The fridge temp is a fairly stable 3C, but when I looked at the EXIF data of even the 30s exposure set, the temp of the first frame was 3C... but by the time it had got to the 20th, it was 12C.

Similarly, 2 weeks ago, although I only actually took 4 x 300s frames , the 1st was 15C (ambient), 2nd 21C, 3rd 21C and 4th 24C. And just for comparison, in mid April the temp rose from 13C to 21C (28 x 600s), and in mid May I recorded start temp of 10C rising to 18C (9 x 600s).

It may be that the extra minute makes the difference(?), but I must admit I haven't seen any noticeable difference in colour balance, only noise...

Link to comment
Share on other sites

[sara - Hope you don't mind me answering Michael's query?!]

Michael - Sara found the "case" for the system on the Wilkinson's website and after about 5 mins of surfing, I found some gelpacks from CPC... It's VERY simple (you just cut a hole in the case for the nosepiece and tape it up), but looking at Sara's recorded temp results, then if it can bring temps down by c. 8C, then that's got to have at least some effect on the noise. However, I obviously need to try 2 minute gaps the next time I use mine :BangHead:.

Link to comment
Share on other sites

Cheers Andy!!

Also Micheal, if you look here, this is Jsigone's photostream on Flickr. If you go to his second page you can see the same system.

I hope it's OK to link so someone else's flickr stream, if not, I'll delete the link.

Link to comment
Share on other sites

Have a look at your specs for the focuser, it will give you a maximum weight. This weights approx 1.7kg and my moonlite specs state that it will hold a maximum of 6lb. So, I am slightly over 50% of the weight, I wouldn't go much higher.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.