DSLR Cooling to Near Ambient with Fan Cooler

[Chris]

UPDATE - Drat!! They're no longer available - should've ordered last night. Drat and double drat! Strange because last night they had hundreds available - didn't think there was that much urgency I have a spare 1100D which doesn't seem to sell so I thought I might make up a twin wide-field setup to take Ha and OIII at the same time.

ah! thats bad luck I was also going to get one for eventually cooling my 350D, especially for 2 pounds!!, hopefully something similar will crop up, your above link looks promising as long as the bids don't go too high! if I can get my little boy down for a nap i'll do a bit of searching myself:) dual imaging rig is an excellant idea, I was searching for another 350D to do the same when my cheap 300D cropped up and it was more in my price bracket:D

bad luck Gina, something will crop up, are the low profile ones any good? I guess they are less efficient but save a bit more space, also would it be possible to attach one to the side of the camera body and blow the cool air parallel to the chip as to save the screen, I know you would have to make vents on the opposite side, I don't know if this is possible its just that I don't use any computer control, although I will with bells on once the obsy's complete!

[Gina]

OH!! Hadn't noticed it's auction only not buy-it-now I'm not very well today - livetsock problems and my cold is now well and truly on my chest

[Cath]

Looks like all your hard work has paid off Gina! .. very cool

Get better soon as well!!

Just did a comparison of your ambient cooled 1100D? to my uncooled 500D (500D's came out in 2009 I think). The Exif temperature is 20C on mine, but I have no idea if that is at the start or the end of the 20min exposure. The camera felt a little warmer to the touch at the end.

You should be happy with this ...

[Gina]

ah! thats bad luck I was also going to get one for eventually cooling my 350D, especially for 2 pounds!!, hopefully something similar will crop up, your above link looks promising as long as the bids don't go too high! if I can get my little boy down for a nap i'll do a bit of searching myself:) dual imaging rig is an excellant idea, I was searching for another 350D to do the same when my cheap 300D cropped up and it was more in my price bracket:D

I think I'll go ahead with the cold finger on my spare 1100D and sort out a cooler later. I have a couple of ones I took off old PCs - one 60mm and one 80mm - that I can try. Neither definitely not as efficient as the new 60mm one but...

When bidding for old M42 telephoto lenses on ebay I ended up with two Vivitar 200mm f3.5 lenses - they look identical so they'd make a great bino system. I can have the Ha clip filter in one and the OIII in the other and double up on my wide-field imaging time per hour of clear sky - seemingly a rare event these days. It will also save me swapping filters all the time.

bad luck Gina, something will crop up, are the low profile ones any good? I guess they are less efficient but save a bit more space, also would it be possible to attach one to the side of the camera body and blow the cool air parallel to the chip as to save the screen, I know you would have to make vents on the opposite side, I don't know if this is possible its just that I don't use any computer control, although I will with bells on once the obsy's complete!

I looked at the low profile ones but I don't think they're really suitable - they tend to spread out sideways rather than upwards. I guess it all depends on your setup and what space there is.

Yes, it should be possible to take the cold finger out of the side of the camera - I did that on my early cooling experiments. It's less efficient due to the extra heat conduction path but might be adequate.

[Cath]

I should add that your mean pixel value on your last dark is now 0.56% of full scale, mine is 6.233% of full scale .. that's a huge difference Gina (11:1 ratio), even though it may not look much on the 3D display.

[Gina]

I should add that your mean pixel value on your last dark is now 0.56% of full scale, mine is 6.233% of full scale .. that's a huge difference Gina (11:1 ratio), even though it may not look much on the 3D display.

Thank you Cath That's certainly impressive and very pleasing for me. I left my setup taking a series of darks while I went to bed. ISO 3200 and exposures of 10, 30, 60, 120, 300, 600, 900, 1200, 1800, 2400 and 3600 secs as I recall. I'll pop out this afternoon and collect the data and see what I've got.

[Chris]

Get well soon Gina, wrap up warm and plenty of hot drinks, also keep an eye on it if its on your chest:)

I really think dual imaging rigs are the way forward, doubling up on the data sounds ideal with our weather:) I think a pair of 200mm lenses at f/3.5 on cooled D1100's would be formidable! it would also look fantastic like a minuture Super Wasp!

Thinking about it, I'm not that far off having the obsy operational so I think I'll attach my cold finger and CPU cooler through the back like yourself, it just seems better that way I think, this is assuming that all the functions I need can be controlled though Backyard EOS, APT etc? I really need to research this computer control stuff:D

[JamesF]

Thinking about it, I'm not that far off having the obsy operational so I think I'll attach my cold finger and CPU cooler through the back like yourself, it just seems better that way I think, this is assuming that all the functions I need can be controlled though Backyard EOS, APT etc? I really need to research this computer control stuff:D

I don't think it would be a problem. I never look at the display or through the viewfinder of my camera these days. APT is much easier

James

[Chris]

Thanks James, this is good to hear, I'll be looking into APT for sure:)

[Gina]

Get well soon Gina, wrap up warm and plenty of hot drinks, also keep an eye on it if its on your chest:)

Thank you Chris Just had a Lemsip hot lemon with honey - not doing much.

I really think dual imaging rigs are the way forward, doubling up on the data sounds ideal with our weather:) I think a pair of 200mm lenses at f/3.5 on cooled D1100's would be formidable! it would also look fantastic like a minuture Super Wasp!

Yes indeed

Thinking about it, I'm not that far off having the obsy operational so I think I'll attach my cold finger and CPU cooler through the back like yourself, it just seems better that way I think, this is assuming that all the functions I need can be controlled though Backyard EOS, APT etc? I really need to research this computer control stuff:D

Having the cooler on the back means a shorter cold finger and better balance, it's also easier to attach it. I used the groove round the viewfinder and the tripod bush.

[Gina]

Here are the last three darks from last night with exposures of 1800s, 2400s and 3600s (30, 40 and 60 minutes). All at ISO 3200 and EXIF T of 10C. These are just the JPEGs resized to 1024px wide - no other processing.

[Chris]

its just sooo good! I really wonder what happened to all the other CPU coolers like the one you used? if only I had a time machine:D although that wouldn't be a good idea, I would be too tempted to go back and visit the cretatious period and I would probably get eaten:D

are these noise readings that much worse then dedicated CCD's? epecially when you consider the cost:)

edit: also when you consider the chip size you're getting with the DLSR!

[Gina]

Managed a very short imaging session last night between the clouds. This is just 6 lights of 300s at ISO 3200 and 10C, no darks, flats or bias frames, stacked in DSS and post-processed in PS, slightly cropped.

[Gina]

its just sooo good! I really wonder what happened to all the other CPU coolers like the one you used? if only I had a time machine:D although that wouldn't be a good idea, I would be too tempted to go back and visit the cretatious period and I would probably get eaten:D

are these noise readings that much worse then dedicated CCD's? epecially when you consider the cost:)

edit: also when you consider the chip size you're getting with the DLSR!

I've often thought a time machine would be handy But, like you say, could be very dangerous.

I find it very strange that the ebay listing for that cooler was withdrawn. I quite expected it to reappear with a much higher price tag attached. But nothing as yet.

I don't really know how these noise figures compare with a dedicated CCD but I reckon they're not so much worse. Of course, for NB work a mono astro CCD would be using all the pixels rather than one of four for Ha and two of four for OIII. The noise for a CCD is better than a CMOS chip though some dedicated astro cameras use CMOS chips and aren't thought to be all that worse. As you say the cost of dedicated cameras is many times that of a DSLR. I intend to prove that a modded and cooled DSLR is fine for DSO AP. I think I'm getting there

[Gina]

Some have commented that with all I've spent on my experiments with DSLRs I could have bought an astro CCD camera. Well maybe - it would have covered an Atik 314L+ but that is just one camera and I intend using three. In any case all this "playing about" has given me a lot of pleasure and has been fun. Sometimes frustrating but often rewarding too.

Also, if I can anvance the general knowledge of cameras for astrophotography and help others on limited budgets make the most of this intriguing hobby by broadcasting my findings, that is a reward in itself

[JamesF]

Did you make progress with your filter wheel, Gina, or is that project on hold pending completion of others? Always thought that would be interesting to see finished.

James

[Chris]

Indeed and well put! yes an Atik 314 would be great but learning how to use an Atik aside, its good to have a challenge, and the reward from all your hard work is visible in your bespoke modded cameras you've made which are im my opinion very cool, I really like this compact version I think its a winner! And you can be proud like you say that you are contributing to astronomy by giving more options to those of us that regularly raid two's and one's jars:D

[Gina]

Did you make progress with your filter wheel, Gina, or is that project on hold pending completion of others? Always thought that would be interesting to see finished.

James

The latter James - on hold. I have learnt a huge amount since I started that project and that has altered my ideas.

As you know I've been putting my efforts into improving the noise performance of DSLRs. I expect that to be coming to an end before long.

Getting the advice to get a focal reducer for my ED80 and the much improved results that has given has rather put a spoke in my filter wheel project, as t'were. I had intended to attach the camera directly to the filter wheel housing. ATM I'm concentrating on the larger DSOs so a focal reducer gives me more coverage but later I expect to be going for the smaller objects and then I won't want the FR/FF but the greater effective focal length without it. And because the objects are likely to be confined to the central area the field flattener aspect wouldn't be as important. Then a filter wheel fixed directly to the camera box and a 2" tube on the scope side would be alright.

Another idea I had was to further butcher an 1100D to get a filter wheel closer to the image sensor such that I could have the bayonet mount on the scope side of the filter wheel housing while retaining the bayonet to sensor distance. This, of course, is really seriously extreme modding - with knobs on! I have doubts that my mechanical engineering skills are up to that sort of precision.

The easiest approach would be to have the filter wheel attached to the focuser and the FR between FW and camera. In that case I would require 2" filters. Without the FR I could get away with 36mm unmounted filters whilst with the "super extreme" camera mod, I could use 1.25" filters.

Of course, with a colour camera like a DSLR I'm only interested in NB filters or none. If, later on, I buy a CCD mono camera (eg. Atik 314L+) I will want a filter wheel with NB plus LRGB filters and 1.25" filters will be fine. I guess I could end up with two filter wheels, one on the DSLR and the other on the CCD but would like to avoid that.

I haven't entirely ignored the filter wheel project. I have given it some thought along the way. I've decided I can use optical position sensing as the LEDs need only be on when moving the wheel - they would be off when imaging so stray light from the LEDs is not an issue. Also, having got into the Arduino, I have thought of using a stepper motor drive rather than a commutator DC motor or a servo.

I shall probably start a new thread sometime soon with my current thoughts on a filter wheel.

[Cath]

It's good to see someone with so much enthusiasm for learning yourself like yourself Gina

[Gina]

Thank you Cath

[Cath]

btw, your latest one hour dark exposure's mean (average) noise level is still 6 times lower than my 20min non-cooled exposure

Amazing just how much 10 deg C can make to the noise level !

[Gina]

Yes, it is

At one stage I was planning to Peltier cool my wide-field camera, now I won't bother - I'll put my efforts into other things instead. I was going to modify my cooling control box to cover two Peltier cooled cameras each with temperature and humidity sensors and Arduino set-point temperature control.

Now I'm going to have two wide-field cameras side by side, each with it's own NB (one Ha and one OIII) filter and 200mm f3.5 lens. I also have two 135mm f2.8 lenses but of different makes (though I doubt this will matter). I may need to order some more nichrome wire for dew heaters Ah... and I must order another M42 to Canon EF adapter. Another piece of mechanical engineering is on the books too - to mount the two cameras on a bar and attach that to the dovetail on the mount. Some way of adjusting the "pointing" of the bino widefield setup and the main scope would be highly desirable so that I can do widefield imaging and narrower (with the scope) at the same time. Currently a Manfrotto ball and socket head provides adjustment for the one WF camera. How about that? Making THREE TIMES the use of available clear skies!

[JamesF]

You'll be needing to build your own upgraded mount soon

James

[Gina]

You'll be needing to build your own upgraded mount soon

James

Interesting thought

Actually, a mini-mount attached to the main mount could provide the control for the widefield system. It would be a lot better than my current way of pointing my WF camera :-

1. Take a long exposure
   
2. Examine image and work out which way to move the camera
   
3. Go out to scope room and move camera a bit
   
4. Go back to warm room
   
5. Pick up chair knocked over in the dark
   
6. Repeat steps 1 to 5 until object is in near enough the right place in the image
   

I could use stepper motors and gearing etc. with the steppers controlled by my favourite microcomputer Oh dear, I feel another project coming on - and just as I was thinking I was catching up as my DSLR cooling projects come to an end

[fwm891]

I'm looking to mount my smaller NEQ3 on the obsy wall for widefield imaging and run that from a laptop in the obsy. I won't always want to shoot widefield of the same subject as the main scope on the NEQ6 and a semi-perm second mount seems better than over loading the main mount and all the balance issues swapping and changing lenses would bring.

Hope you're feeling better Gina