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MarsG76 last won the day on August 30 2018

MarsG76 had the most liked content!

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About MarsG76

  • Rank
    Main Sequence

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  • Gender
  • Interests
    Obviously Astronomy... Observing and Imaging.
    Gym, Down to Earth Video and Photography. Tinkering with and engineering electronic devices.
  • Location
    Sydney, Australia
  1. MarsG76

    DSLR Active cooling MOD process - Part 2

    Everything is tight with heat transfer paste... the NTC should report the accurate temperature since its tight against the copper plate, even if the sensor might not be to the temperature.. but believe me, its all very tight... I'm missing something.....
  2. MarsG76

    DSLR Active cooling MOD process - Part 2

    That is one neat and tidy project.. BUT... look at the tiny heat sink with the tiny fan he is using.. HOW does ho go from 30 deg to 0 with that??? Got me thinking.. he stated that he is powering the kit with a 4A PSU.... I did some measurements and I'm running 8Amps on the two TECs, fans, and temperatures controller, but still stopping around 10 degrees below ambient when the camera is OFF... when on it goes down from 25 to 18 as before so I thought I'll setup other TECs on a massive heat sink and fan as well as measure the temperature of my very first cooling project... The Big heatsink has the TEC sandwitched between it and a small heat sink, the NTC in the middle grill and the whole thing sitting on a Styrofoam block..... the resulting lowest te mperature is 18.2... thats when the TEC is hooked up to a 50A 12V PSU and the heat sink is not even getting warm, so heat dissipation is definitely effective. The second setup, the first project, draws 9 amps for the two peltiers and fans, the heat sinks get quite warm, and the result lowest temperature is... 13.1 Both of these cooled items, small heat sink or the case of the DMK41 are WET with dew.... Whats going on? I cant get below 11.7 after about 60 minutes of cooling on the two TECs on the DMK but thats nowhere near freezing.... it reached 13.1 in 20 minutes than slowly went to 11.7... also the DMK is not powered... The fan on the big heatsink has a speed control pot and the funny thing I noticed is that when I had it running max speed the temperature didn't drop below 18, but when I turned it to minimum speed, quite quickly, the speed dropped to 16 and stopped there... so I disconnected one of the extra fans on the DSLR, the bottom one of which extracted air from the fins and seeing if this will make any difference to the lowest temperature. What am I missing?
  3. MarsG76

    DSLR Active cooling MOD process - Part 2

    Very interesting... initially I thought that perhaps I'm not dissipating enough of the peltier heat, but it is just warm to touch so I don't think that heat bleeding on the peltiers is the problem... BUT I'm juggling now whether I should re-wire the two pletiers in series, this way they'll both run at half voltage and perhaps increase the efficiency of the cooling with less heating.... and OR my copper plate it too thin, (1.3mm thick) to effectively extract the heat from the sensor?? Which would be a problem because there is no way I can fit a thicker plate inside the camera, already I had to squeeze the unit shut, so I'd have to live with the 32 degrees plus down to ambient (which does improve slightly). I'm using ebay 12706 peltiers from China, so perhaps they're not as good as they should be??? Get what you pay for?? My other option is to wait until winter and see how far the camera is cooled to when the climate is not so hot... night time 25 degrees C but feels more like 30... and so the cooling is struggling.... Either way, so far I do have an improvement so it's a start.... and good news is that the camera survived another night...
  4. Thanks for that.. I know it's been posted a while ago but this is exactly what I was searching for.
  5. MarsG76

    One year (and a bit) on

    Woo... not many (if any) other places where I fit into the top 0.186%!!!
  6. MarsG76

    Nikon D5100 active cooling

    Hi, I attempted to cool my DSLR and I'm wondering what is the ambient temperature that you're imaging at to reach and sustain -4 degrees? I am cooling my DSLR with two very insulated peltiers on two sides of the copper plate and can not get below 16 degrees, mind you that my ambient is 25 degrees at night, generally my 15-30 min subs are exposed at 22-24 degrees when cooled where uncooled subs are heating upto 38 degrees.... is the difference between the temperature you're reaching and i'm getting the ambient we image at? Link to my project is here:
  7. MarsG76

    DSLR Active cooling MOD process - Part 2

    Hi All, I modded another 40D... this time I squeezed very think foam sheets on the cold finger and into gaps where I could, I sprayed expanding foam into the gap where the copper plate goes into the camera, inserted silica gel packets into the card compartment, I added a thin NTC sensor between the sensor and the cold finger for accurate sensor temperature reading and added another fan to help dissipate the heat off the heat sinks. I had the camera running for 2 nights at 80% humidity and a dew point temp of around 20 degrees.. roughly the same conditions as during the nights when I lost my camera before... and this time the camera survived, so perhaps the foam did the trick, thanks for the suggestion @Stub Mandrel and @Thalestris24.... time will tell if my camera can survive the dew.... I'll tell you that with the foam inside the whole assembly is TIGHT.... very tight.... Here are my findings... when I'm exposing my subs at ISO1600, a 30 minute (15 minute also) settles at about 1 degree below ambient according to the NTC between the sensor and the cold plate.... when not exposing but the camera is on than it falls only about 8-9 degrees below ambient... when the camera is off than I get to about 10-12 degrees below ambient. the ambient temperature is 25 degrees C at midnight being summer time.... Now the EXIF temperature reported by APT coincides with the NTC reading... so the EXIF temperature on cameras looks to be accurate. When exposing the same ISO and duration subs with the cooling turned off the sensor temperature rises to 32-34 degrees C (actually seen it go up to 38 once)... so I guess its an improvement of around 8-10 degrees... So my question is do these numbers look right, considering the ambient temperature and considering that I do have two peltiers running and cooling the copper plate back to back which are quite well insulated and the heatsinks are not too warm at all with all of the fans blowing and sucking air through them? I read about how some of you get ice forming and reach -5 degrees etc, is that because you're cooling your camera at a much lower ambient temperature to begin with?
  8. MarsG76

    Any Free Sharpcap alternatives?

    +1 for Firecapture. I use this program for planets, lunar and solar captures... stills or time lapse captures... My other alternative is IC Capture or iCap as it's now known since Celestron joined with imaging source.
  9. MarsG76

    Any Free Sharpcap alternatives?

    For 14 months???
  10. How cool does that look.. nice one..
  11. Fantastic images... love the composition.
  12. MarsG76

    UHC for planets

    Yes, and it takes away from the detail, intensity and creates a strange hue across it.. my recommendation is a neodymium and contrast booster (in that order from the eyepiece out) to really enhance your views.... it is amazing just how much detail I picked up with my 8" SCT and 14" dob on the clearest nights with the use of those filters.
  13. MarsG76

    My Lunar Eclipse in Pictures

    Might not be 9, but it's still a few good years... I'm looking on the positive side of things... that when it does come around, my son will be old enough to enjoy it too....
  14. Even though it's a bit over the budget you have mentioned... I couldn't recommend the Celestron 8SE enough... that scope will serve you for ages.. mine is around 10 years old and it still gives me some of the best views most nights.. all except the RARE clearest nights, it out performs my 14" dob on planets....

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