Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

ASI071 MC Pro Wont cool to selected temp

  • Please log in to reply
7 replies to this topic

#1 birddog99

birddog99

    Vostok 1

  • -----
  • topic starter
  • Posts: 115
  • Joined: 21 Aug 2017
  • Loc: Houston, Texas

Posted 18 January 2019 - 11:47 PM

A good friend in our astro club is letting me try his ASI071 MC Pro. When I select a temperature to cool down to, ie: -20, -10, I watch the temp drop down on the display down to almost the temp I select, but it wont get to within 5 degrees of the temp I select. I verified this in Sharpcap pro and SGP. Out of 5 imaging sessions over the last 2 weeks, only 2 sessions had the temp reaching the selected temp. Dew heater on or off doesn't matter. The cooler will run at 100% during this time. I'm wondering if it's a camera issue or a software issue. The correct ASCOM drver is installed. Ant ASI071 users have this problem?



#2 AhBok

AhBok

    Surveyor 1

  • *****
  • Posts: 1756
  • Joined: 02 Dec 2010

Posted 19 January 2019 - 12:02 AM

It sounds more like a cooler problem. What is your ambient temperature? Mine easily cools to 35c below ambient, more if I run above 80% power. Are you sure your fan is running? Do you have at least a 5 amp supply? Have you measured your voltage under load?

#3 ThatsMyCoffee

ThatsMyCoffee

    Mariner 2

  • -----
  • Posts: 258
  • Joined: 15 Dec 2017
  • Loc: Czech Republic

Posted 19 January 2019 - 01:31 AM

Sounds like your temp setting is just too low.  It should do 35c below ambient.  If it won't, contact zwo.

 

What is the outdoor temp and what temp are you trying to reach?


Edited by ThatsMyCoffee, 19 January 2019 - 01:32 AM.


#4 birddog99

birddog99

    Vostok 1

  • -----
  • topic starter
  • Posts: 115
  • Joined: 21 Aug 2017
  • Loc: Houston, Texas

Posted 19 January 2019 - 03:52 AM

5amp power supply confirmed. I'm inside now running Sharpcap. Ambient temp is 25.3C. Target temp -10.0C.  After about 5 minutes the cooler settled in at 68% and locked in at -10.0. I lowered temp setting to -20.0C and with the cooler running at 100% the lowest temp it reached was -16.1. It would go back and forth from -16.1 to -15.4 while cooler running at 100% So if it should do 35C below ambient, then -10 is all I should expect for it to cool to, right? So maybe all is ok, and it's the ambient temp that is the issue.



#5 jgraham

jgraham

    Hubble

  • *****
  • Posts: 19717
  • Joined: 02 Dec 2004
  • Loc: Miami Valley Astronomical Society

Posted 19 January 2019 - 08:12 AM

When my camera is out on the scope I like to keep my TEC load no higher than 30%. While colder is better, what you are really after is thermal stability. I run my ASI071MC Pro at 0 to 10C in the summer, -10 to -20C in the winter. When taking darks inside I never run the TEC below -10C.

Sounds normal to me. Make sure that the air vents are clean and clear.

Edited by jgraham, 19 January 2019 - 08:13 AM.


#6 Der_Pit

Der_Pit

    Messenger

  • -----
  • Posts: 469
  • Joined: 07 Jul 2018
  • Loc: La Palma

Posted 19 January 2019 - 10:02 AM

5amp power supply confirmed. I'm inside now running Sharpcap. Ambient temp is 25.3C. Target temp -10.0C.  After about 5 minutes the cooler settled in at 68% and locked in at -10.0. I lowered temp setting to -20.0C and with the cooler running at 100% the lowest temp it reached was -16.1. It would go back and forth from -16.1 to -15.4 while cooler running at 100% So if it should do 35C below ambient, then -10 is all I should expect for it to cool to, right? So maybe all is ok, and it's the ambient temp that is the issue.

Correct, nothing is wrong. The cooler is not specified to reach some absolute temperature, only a drop of (approximately) 35-40 degrees below what it would have without cooling (i.e., the ambient temperature).

As jgraham mentions, as soon as your cooling power hits 100% your camera temperature will not be stable anymore, but vary with the ambient temperature.  And constant is much more important than low.  Just make sure you take darks at the same temperature!



#7 birddog99

birddog99

    Vostok 1

  • -----
  • topic starter
  • Posts: 115
  • Joined: 21 Aug 2017
  • Loc: Houston, Texas

Posted 19 January 2019 - 11:28 AM

Got it. Thanks, guys



#8 Alex McConahay

Alex McConahay

    Fly Me to the Moon

  • *****
  • Posts: 7309
  • Joined: 11 Aug 2008
  • Loc: Moreno Valley, CA

Posted 19 January 2019 - 11:36 AM

Put your camera in the freezer in the kitchen, and see how cold it can get. It should be getting to -15 or so without much power at all. This is a test to see if it has the cooling capacity.

Alex




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics