Hi guys
After an imaging session with my Atik 314l set to a cooled temp of -15, when I turn off the cooler does AA5 start a slow warm up procedure or does it switch off the cooler instantly please?. I assume it would enable a slow warm up given the detail applied to the rest of AA5! Wanting to avoid any shock to the ccd sensor!.
regards
Steve
Warming up after cooling ccd?
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Forum_2015
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Re: Warming up after cooling ccd?
Hi Steve, I can't answer your question about weather AstroArt warms up slowly, but I don't think it does. The CCD is insulated inside the camera and for that reason can only warm up slowly. Thermal shock would require a very rapid temp change. What I did was asked SBIG what they thought! Try asking Atik what they recommend. If it makes you feel better you can write a script that will allow your camera to warm up slower. See the AstroArt script commands in the user manual.
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Forum_2015
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Re: Warming up after cooling ccd?
Hi Iver
Thanks for the reply!. Recently I`ve been using Astro Photo tool - `APT` for imaging spectra and it offers a `warm up` option where you set the desired temp and it then gradually warms up in increments with a pause in between over a defined period . I noticed when I last used AA5 and turned off the cooler the word `warming` appeared in the cooling window which I assumed indicated a specific procedure built in to AA5?. Maybe AA5 has a built in script for this already?.
regards
Steve
Thanks for the reply!. Recently I`ve been using Astro Photo tool - `APT` for imaging spectra and it offers a `warm up` option where you set the desired temp and it then gradually warms up in increments with a pause in between over a defined period . I noticed when I last used AA5 and turned off the cooler the word `warming` appeared in the cooling window which I assumed indicated a specific procedure built in to AA5?. Maybe AA5 has a built in script for this already?.
regards
Steve
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Forum_2015
- Posts: 353
- Joined: 07 Dec 2018, 15:04
Re: Warming up after cooling ccd?
Hello Gasman,
from what I know, thermal stress induced by the warming up process can produce mechanical problems only when the sensor surface is a big one, I assume the case when you have a sensor within 35 mm range or more. For smaller sensors the thermal inertia (warming up procedure when the cooler is shut down) is not a problem because the sensor warms up a little bit slower (dissipation surface is smaller). I have 3 CCD camera (1602E, 8300M and the sensor from the guider Atic16IC) and the warm up time till the sensor is reaching the ambient temperature is relatively long. Sure, if you want to stay on the safe side you can consider a slower warm up but for standard CCD used by 90% of astrophotographers this problem is not that important. I also believed that maybe is better gradually warming up the CCD but from my experience is not that relevant. The other side, one of my cameras, the one with the 1602E sensor, is using a different cooling approach as the QHY9m, the qhy is slowly increasing the cooling power but the 1602E is running from start at 100% and after reaching the desired temperature, is starting to regulate the cooling so, in this case, the mechanical stress produced by cooling is higher as the one produced by warming up because the delta temp in the cooling phase is higher as the delta t in the warm-up process.
Case: -30°C sensor temperature 1602E sensor
Cooling: delta t about 5°C/minute
Warming up: delta t about 3°C/minute
Keep in mind: the warm up delta t depends on the size of the metal plate behind the TEC element, also don't forget that the metal plate is alway warm because it has to transport the heat from the warm side of the TEC - peltier element mostly 2 of them in cascade).
Hope it helps
Clear skies
Emil
from what I know, thermal stress induced by the warming up process can produce mechanical problems only when the sensor surface is a big one, I assume the case when you have a sensor within 35 mm range or more. For smaller sensors the thermal inertia (warming up procedure when the cooler is shut down) is not a problem because the sensor warms up a little bit slower (dissipation surface is smaller). I have 3 CCD camera (1602E, 8300M and the sensor from the guider Atic16IC) and the warm up time till the sensor is reaching the ambient temperature is relatively long. Sure, if you want to stay on the safe side you can consider a slower warm up but for standard CCD used by 90% of astrophotographers this problem is not that important. I also believed that maybe is better gradually warming up the CCD but from my experience is not that relevant. The other side, one of my cameras, the one with the 1602E sensor, is using a different cooling approach as the QHY9m, the qhy is slowly increasing the cooling power but the 1602E is running from start at 100% and after reaching the desired temperature, is starting to regulate the cooling so, in this case, the mechanical stress produced by cooling is higher as the one produced by warming up because the delta temp in the cooling phase is higher as the delta t in the warm-up process.
Case: -30°C sensor temperature 1602E sensor
Cooling: delta t about 5°C/minute
Warming up: delta t about 3°C/minute
Keep in mind: the warm up delta t depends on the size of the metal plate behind the TEC element, also don't forget that the metal plate is alway warm because it has to transport the heat from the warm side of the TEC - peltier element mostly 2 of them in cascade).
Hope it helps
Clear skies
Emil
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Forum_2015
- Posts: 353
- Joined: 07 Dec 2018, 15:04
Re: Warming up after cooling ccd?
Hi all,
When I push the [cooler off] button in the camera setup and go back to the camera window, I can see that the working percentage is slowly dropping to zero% and the temperature is slowly rising accordingly. I use an ATIK 314+ through Ascom....
So I guess it isn't shut down instantly
When I push the [cooler off] button in the camera setup and go back to the camera window, I can see that the working percentage is slowly dropping to zero% and the temperature is slowly rising accordingly. I use an ATIK 314+ through Ascom....
So I guess it isn't shut down instantly
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Forum_2015
- Posts: 353
- Joined: 07 Dec 2018, 15:04
Re: Warming up after cooling ccd?
Some high priced older camera have had implemented in firmware a warm up procedure to eliminate the mechanical stress.
The new ones are getting cheaper and are getting bigger sensors, also because the prices for the components (CCD sensor, electronics, memory to buffer the image before read-out) are going lower, this way the producers can offer instruments with bigger sensors for relatively competitive prices. So they (the producers) have to implement in cameras some protections measures and one of them is the thermal protection.... The old middle range and low cost cameras have turned off the TEC and game over...
ajtdebruin
I would love to know what happens in camera when you disconnect the power supply from it.... just theoretically what delta t value will a reading device show...
The new ones are getting cheaper and are getting bigger sensors, also because the prices for the components (CCD sensor, electronics, memory to buffer the image before read-out) are going lower, this way the producers can offer instruments with bigger sensors for relatively competitive prices. So they (the producers) have to implement in cameras some protections measures and one of them is the thermal protection.... The old middle range and low cost cameras have turned off the TEC and game over...
ajtdebruin
I would love to know what happens in camera when you disconnect the power supply from it.... just theoretically what delta t value will a reading device show...
