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Showing results for tags 'peltier'.
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ZWO ASI385MC Peltier Cooler
Stargazer33 posted a topic in DIY AstronomerWhilst browsing through astronomy videos on YouTube, I came across a couple of videos on fitting a peltier cooler to standard ZWO cameras. I had been thinking of doing this to my ASI385MC since I made a coolbox for my DSLR back in 2016. Martin Pyott's (Astronomy 4 Beginners) build just had a heatsink and fan; Ewan, Astronomy Addict added a cheap Chinese temperature sensor and controller. I have added a cpu cooling unit instead of just a fan: I purchased a hotshoe adaptor from ebay to use to attach the cool plate to the camera and to act as a bit of a cold finger, getting as close to the sensor as I could without actually opening the camera. I chose an aluminium one as the thermal properties would be the same as the camera body. I had to cut down the thread to fit into the tripod mount hole on the camera and also round off the corners of the hot shoe plate to fit into the recess I cut into the cold plate in order to get a flush surface for the peltier to sit against. I used an old forstner bit to remove just enough material from the cold plate to allow the hot shoe adaptor to sit flush. I bought the Arctic Freezer 34 esports tower cpu cooler to help speed up heat dissipation from the hot plate side of the peltier. The cold and hot plates are 100 x 100 x 3 mm aluminium plates. The Arctic Freezer 34 esports come with various fixings for different CPUs, including double ended threaded stand-offs. Drilling and tapping four holes in the corners of the cold plate allowed me to screw these in. I cut some thin foam I had lying around to 100 mm square and cut a hole in the centre the size of the peltier. I poked the wires through the foam and then using some MX-4 thermal paste on the cold side of the peltier, I placed the foam/peltier onto the cold plate. More MX-4 paste was spread onto the hot side of the peltier and then the hot plate, with larger holes cut into the corners so the stand-offs could pass through, was placed on top. Yet more MX-4 paste was spread onto the plate of the cpu cooler and this was then attached to the stand-offs using the supplied thumb nuts (?). The camera screwed onto the cooler: The next part was a bit of a pain! I couldn't find a project box of the dimensions that I wanted and the one I eventually bought had large areas cut out to enable securing , which left me with even less room for the wiring. This coupled with the atrocious Chinese to English translation for the temperature controller had me muttering under my breath some rather unpleasant things! Eventually I managed to get everything wired up, but not before I had to order another Bionix fan after allowing the magic factory smoke to escape from the original one when I got the wiring mixed up! I knocked up a small bracket to mount the control box to the cooler and with the temperature probe placed next to the camera I put the insulated cup around the camera body. I forgot to take a picture at the time, but during the first trial, I had a reading of 4°C from the temperature sensor and it was still falling when I turned the unit off. As I was testing it inside, a lot of condensation was forming on the cold plate and on the nosepiece and ir/uv filter of the camera. The sensor however looked clear. I may have to buy one of the ZWO camera dew heater units or possibly knock something up myself to keep the filter clear of condensation. With hindsight I think I should have gone for a cpu cooler of this design: This would mean less side force on the nosepiece.
How to cold finger mod 1000d?
Astro-gorilla posted a topic in DIY AstronomerHi everybody!! Just joined after lurking for a year. I have done the filter removal as instructed by Gary Honis and was satisfied with the results. Only one thing I'm wanting to learn and that's how to do a cold finger mod on my canon 1000d. I have found some links, but mostly any instructions I've found were outdated and removed from the web, so it's been difficult to find a mod to my liking with detailed step by step and supply list. One of my main concerns is that I still want to use the side of my camera that has usb and the input for my intervalometer (currently unguided with no laptop). I can do without live view as long as I can still connect the dslr to my phone on dslr controller for a bigger more comfortable live view. Anyways I really need help in the right instructions to get this done. Any links, videos, or experienced instructions would be a big help and I would be very thankful for. I'd also like to add that I would like to go light weight on the mod, so i don't have much trouble balancing the es 80mm triplet on an Orion sirius. Trying my best at a budget to defeat the Texas summer. Clear skies!
DIY cooler for asi178
D4N posted a topic in DIY AstronomerI've decided to have a play around with some DIY cooling and bought a 5V peltier cooler to do this. Now I went for 5V as I wanted to be able to power it from a USB port, I have some battery packs that are designed for charging up phones and tablets that will come in handy for portability. The ZWO cameras are quite well designed for this type of thing as they have a large flat backplate that the cooler can be attached to. I used a thermal interface pad to attach the TEC to the back of the camera and another one to attach a CPU heat sink with fan from an old computer. The fan and cooler are then connected up in parallel to two battery packs or to a single 5V mains adaptor. Now for the testing, I ran the camera in video mode for a while and the temperature settled at 36.7°C with no cooling on. I kept the gain at 255 throughout the tests. When I turned the cooling on the temperature quickly dropped down to 16°C. Next I did some longer exposures, after a 5min exposure with no cooling it reported that the temperature was 32.2°C and on inspection the average pixel value was 1187. Now with the cooling on I took another 5min exposure and it reported the temp as being 10.2°C and the average pixel value was 216. I took some 1min exposures as well, these came up with a pixel value of 198 for uncooled and 17 for cooled. I noticed that a lot of this noise was in the corners, I assume that this is amp glow or other interference from the internal electronics so I cropped it and the average pixel value dropped to 180 for uncooled and 8 for cooled. Cropping the 5min exposures brought the average pixel value down to 1038 for uncooled and 80 for cooled. This seems to be a resounding success so far as noise reduction goes, I expect that the amp glow can be dealt with using dark frames as it isn't random noise. I also noticed that the majority of the noise is in the same pixels in the cooled exposures, as such it should respond well to dark frames or a bad pixel map. I plan to use this with some camera lenses I have as a super portable setup, maybe it will be portable enough to take somewhere with no cloud
Canon 1100D set-point cooling mod
Jokehoba posted a topic in DIY AstronomerI thought I would share with you last summer's project to add set-point cooling to my DSLR. It took about 3 months and wasn't actually required much over the cold winter months. I've made a few minor changes since the winter. The original white-on-blue display packed up so I replaced it with this black-on-green one. And the original ball-bearing fan introduced vibration when using my SCT (not apparent on my other scopes), so I've replaced it with a MagLev/vapo type. Unfortunately I haven't had any clear skies to test the new fan... My main design criteria were: Cold-finger/peltier cooling As little 'destruction/deconstruction' of the camera as possible - I wanted it to still look like a DSLR Achieve 5-10 C set-point cooling, as I felt this gave acceptable low noise Include a dew heater/indicator for the front filter Arduino controlled with display to provide useful feedback on settings and simple controls I give due credit to Gina and Rowland Cheshire, having read their many inspirational posts on cooling (both here and on Ice in space) which helped me to hone my design. Image with the camera shows fan-heatsink-peltier-bracket construction. The connection box is screwed to the tripod mounting. The white sensor measures ambient temperature and RH. The controller images show approaching the set-point and at set-point. A red LED above the main display lights up when the dew heater is active. The display shows: Set = desired set-point temperature CMOS = temperature of cold-finger close to sensor Fltr = temperature of front filter Dew = number of degrees above the dew point to maintain the dew heater TEC = heatsink temperature (hot side of peltier) PWM = percentage output sent to the peltier (I've limited it to 90% max) Am = ambient temperature, DP= dew point, RH = relative humidity At some point I will tidy the heatsink side to conceal the cables, etc. John
DSLR Coolbox Build
Stargazer33 posted a topic in DIY AstronomerAs I haven't had any sessions for a while I needed something to do with my astronomy before I forgot what it was all about. So, (don't you hate it when people start a sentence with "So"!) having read an article in Astronomy Now about building a Peltier controlled coolbox for a DSLR camera I thought I would give it a go. My main reason for doing this is that I am not too keen on taking my DSLR apart to do the more radical Peltier cooling that some members have done. Yes Gina, I'm looking at you! My coolbox is slightly upgraded from the one in the article as I have put a copper ribbon cold finger from the Peltier exchange heatsink to around the DSLR body (bottom and back). The Peltier cooler was purchased off of the internet and came all the way from China in a plastic bag with a bit of bubblewrap around it so needless to say it was damaged when I received it, but nothing I couldn't fix and I wasn't going to send it back for only £8. The insulation was from an old camping mat that I bought some time ago to make a dew shield from but was too floppy! The box was one of those food storage boxes that locks twice and the copper was 'rescued' from the scrap bin at work! The power to the DSLR is via the battery hack that can be found in this forum. After completion I ran a test indoors and recorded the results via APT which give a cmos temperature reading from the RAW file. Room temperature was a steady 23.5 deg C throughout the test. I set up APT to take 100 frames with a 60 second gap between each frame. The first few readings were at 24 deg C, by the time the test ended APT was reporting a cmos temperature of 13 deg C. That's an 11 deg C drop in temperature over the course of the test and a 10.5 degree drop over ambient temperature. All I need now is a clear night to test it out in the real world.
QHY5L-II Mono Options for Passive / Active Cooling
SnakeyJ posted a topic in Discussions - CamerasOkay I've had my QHY5L-II mono for just over a month and have been itching to take a look under the hood to consider options for cooling this super little camera. The camera uses the Aptina MT9M034 1.2Mpix (1280x960 active pixel) 1/3" sensor with Peak QE at 74% (datasheet available at http://www.aptina.com/products/image_sensors/mt9m034/). This is the same sensor used in the ZWO ASI120MM. The current drivers/firmware support shutter speeds from 0.020s to 600s, 14bit ADC giving 8bit or 12 bit colour depth and with USB2 interface and ROI support can produces some very respectable frame rates even on Saturn ( 400x400 ROI @ 8bit giving 75FPS for L @ 85% gain, 65FPS for R @95% gain - dropping to around 45-50FPS for B @ 99% gain. Noise levels seem very good, even at max gain for shorter exposures, way better than my previous experience with the Pt Grey Firefly Mono - but there are a few (3-4) hotpixels showing up on high gain short exposures and the noise levels build up with exposure length. The camera body is noticeably warm to the touch during extended video capture and this will only worsen as ambient temps increase towards summer. Interestingly, QHY list a 'Super Radiator' accessory for this on the product data sheet. Though I have been in contact with QHY, who say this is not available currently and were unable to advise on manufacture/availability - though did clarify that it would be a passive sleeve/fin design to slip over the 1.25" body of the camera. My curiosity suitably piqued and finding no information on the internals or cooling mods online - I decided to risk voiding the warranty for a little (cautious) investigation: The good news is that the camera is very nicely made and is already designed to draw the heat of the cmos and main processor via an internal aluminium bulkhead to the outer case. So it should be very simple to make an external passive heatsink and fan. For active (TEC) cooling it would be very simple to add an external 20-30W peltier fitted to a copper collar and it should also be possible to fit a smaller device 5W? directly to the back of the bulkhead. The case itself would lend itself to fitting a small dessicant tube and the modular construction and long ribbon cable would also make it very suitable for rehousing in a custom case if desired. Given the experience with cooling the firefly, I think this offers considerably more options for a neater and more efficient cooling solution and I would hope to easily achieve 25-30 deg below ambient with 80-85% reduction in noise at max gain. Given the current price of £ 229 (roughly 8x what I paid for the firefly), there is certainly more financial risk - but the mods look far simpler and will avoid any direct contact with the CMOS, so I feel well up for the attempt!