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MarsG76

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    5,273
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MarsG76 last won the day on August 30

MarsG76 had the most liked content!

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About MarsG76

  • Rank
    Main Sequence

Profile Information

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

    First APP Mosaic - I'm impressed!

    Very nicely done... especially for a first.
  2. MarsG76

    Well that doesn't look good does it?

    Yeah, I'm right there in the same boat with you.....
  3. MarsG76

    Venus - 16 August 2018

    Yes agreed, there is something mesmerising about venus in the eyepiece...
  4. MarsG76

    DSLR Active cooling MOD process - Part 2

    As I was exposing last night, I noticed that one of the peltiers isn't working, so one peltier was all that was used with a heat sink and fan on the other side... Temperature wise it didn't seem to make so much difference, if any... but I might have had a faulty/open circuit peltier from the beginning... Do peltiers fail easily?
  5. MarsG76

    Fuzzy Thing near Aldebaran

    A reflection perhaps?
  6. MarsG76

    DSLR Active cooling MOD process - Part 2

    Yeah, I figured that the heat sink might be too small, but so far the result is OK with the fan overkill shown above. Another mod I might do later is place a thick piece of copper between the peltier and the heatsink to increase the gap between the heat sinks and the copper plate, and fill the gap with expanding foam, which is (allegedly) the best temperature insulator outside of a vacuum that is easily available.
  7. MarsG76

    DSLR Active cooling MOD process - Part 2

    Having to solve the heat feeding back problem, I decided to put another peltier/cheat sink on the other side of the copper plate and styrofoam in between the heatsinks and the copper. I built a simple circuit board to power to the fans and the temperature controller as well as a relay circuit which supplies power to each of the pletiers through a relay, separating the current flow per veroboard track as initially having the total of 11.8 amps for both peltiers on one track did fry it. As the heatsink fans are blowing air into the heatsinks, I also added two fans on the top and bottom of the heatsinks to speed up the extraction of the heat within. Now the temperature drop was 10 degrees and stable, as reported by the NTC, but after a while I saw moisture forming on the exposed cold finger so again I'm guessing that the temperature was a lot lower than around the 16.5 degrees that the temperature sensor was showing. This test was performed inside during a warm evening, so for dew to form on the copper I imagine that the temperature was closer to the 5 degree mark. OK, it was time for another dark frame test, again gain was ISO1600 but this time I'll expose the dark frames for 1800 seconds, which is the time I generally spend per sub for my narrowband imaging. I did another dark sub test with the top fan blowing into the heat sinks for comparison. The result was substantial.... What this shows is the darkframe comparison uncooled to cooled with, first, the top added fan extracting... than with the added fan blowing into the heat sink. This is a comparison to subs on the left which are RAW unprocessed with all of the noise intact. Photoshop CameraRAW does reduce noise as it converts to TIFF, and does a pretty good job of it, as shown in the center, As a final step I pre-process the subs with a "Dust & Scratches" filter to remove the individual pixels which were left by CameraRAW... 2 pixels @ threshold 30 did a good job of only removing the noise/overactive pixels resulting in subs with the noise level shown down the right side. These are the subs I would normally stack. All of these pictures are center cropped 640x480 from the original files. The orientation of the top fan made little difference but by having both fans extracting the warm air, it seems to have had the edge and so that how I'll keep the fans for the final version. I started doing some wide angle imaging, mostly as a test. The wide angle subs are 120 second subs at ISO 1600 and so far the results are awesome... my subs are noise free. Next clear night I'll image some long exposure narrowband subs through one of the scopes. Since the current state of the setup has cables, the circuit board and temperature controller hanging down and held in place with alligator clips, I'll have to clean up the whole cooled DSLR setup into a nice package with only needing to plug in the power supply. I might also try to move the temperature probe into a place where it'll report a more accurate actual sensor temperature. So far I'm very happy with the results. Clear Skies, MG
  8. MarsG76

    DSLR Active cooling MOD process - Part 2

    Hello All... Thanks everyone for your help and info during my cooling mod of my DSLR. I do believe that I had a bit of success. The cooling worked initially but as the heatsink heated up, it in turn heat up the copper plate and as a result the peltier was in a loop trying to cool itself... ultimately the temperature dropped around the 10 degree mark but soon rose 5 degrees and that's where it stabilized. Even though the temperature drop was not great, I did do a dark frame test... This was the result of uncooled and cooled ISO1600 darks... 24 vs 19 degrees. I did allow it to cool for 20 minutes before I exposed the cooled sub. The exposure time was 30 minutes on relatively cool night... so there is a bit of a difference in the amount of noise in the raw dark subs. Eventhough there is a drop in the noise level, its not enough..... Note that the actual temperature drop of the sensor might be lower than reported since the NTC proble does not sit on the sensor or the cold finger.
  9. MarsG76

    Celestron C5 OTA & focal reducer.

    I dont see why not... the theory is the same as for the C8/9 SCTs.
  10. The windows fix works again....
  11. MarsG76

    Tis the season !

    Very dark adaption preserving festive decoration.
  12. MarsG76

    Mars /Neptune encounter animation

    Very nice... the flare effect does look cool..
  13. Great image... When I saw your reflections, the first thing I through of was.. are you using a focal reducer? I seen something similar on one of my orion nebula exposures with a focal reducer inline when there was a brightish star just out of frame.
  14. As well as DeepSkyStacker, there is also Nebulosity....
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