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ZWO asi294mc-pro or not pro

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#1 Iones

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Posted 16 September 2021 - 09:06 AM

Hi,

 

I am interested in upgrading my zwo asi178mc to an asi294mc and use the 178 as guide camera. (edit: the 294 would be used exclusively for deep sky)

 

I saw there are two models of the 294, one is cooled the other is not. If the sensors are identical is the 300$ (400 cad) difference worth the cooling?

Are there any other differences between the two models except the cooling?

 

Furthermore, I see that the pixel size is quite big (4.63 um), what would be the smallest refractor I could use with this camera ? Is the limiting factor, the focal length, the aperture or the F/ratio.

 

The well depth on the camera is 63.7k, could that have any disadvantage or is the deeper the well the better (the 178 has 15k)?

 

What about filter size, would 1.25 inch filters work with this camera?

 

Lastly, are there any other issues about this camera I should be aware of?

 

Thank you for your time,


Edited by Iones, 16 September 2021 - 09:34 AM.


#2 jgraham

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Posted 16 September 2021 - 09:25 AM

I have both. The primary differences between them is the TEC on the Pro along with the added size and weight of the TEC. The ASI24MC is a fantastic uncooled lightweight camera and is very well suited for lunar and planetary imaging and basic deepsky. The Pro is a tad better at lunar and planetary (runs a little cleaner when cooled) and much better at deepsky. For planetary the pixel size is fine and you can use ROI to hit high frame rates. If you are interested in deepsky the Pro is a great option. The uncooled is a nice option if you want a simple, lightweight camera.



#3 Iones

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Posted 16 September 2021 - 09:30 AM

I have both. The primary differences between them is the TEC on the Pro along with the added size and weight of the TEC. The ASI24MC is a fantastic uncooled lightweight camera and is very well suited for lunar and planetary imaging and basic deepsky. The Pro is a tad better at lunar and planetary (runs a little cleaner when cooled) and much better at deepsky. For planetary the pixel size is fine and you can use ROI to hit high frame rates. If you are interested in deepsky the Pro is a great option. The uncooled is a nice option if you want a simple, lightweight camera.

Thank you for your answer,

 

I should have specified this camera will be only for deep-sky, my 178 is wonderful at planetary.

 

If I understand you would recommend the cooled version.



#4 Tiago Ferreira

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Posted 16 September 2021 - 05:20 PM

i have the uncooled and it works fine. During summer i use a DIY mini cooler to lower below 30 degrees celsius which is enough for me. otherwise noise appear. i just do EAA and planetary AP though. If i would do AP with long exposures i would go with the cooled version specially in a warm weather site.
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#5 Jaimo!

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Posted 16 September 2021 - 09:32 PM

Deep sky get the Pro, it might seem like a big difference now, but it gets smaller with the images and ease of darks and flats.


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#6 DJL

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Posted 16 September 2021 - 11:18 PM

With a cooled camera you can set a standard temperature like -10C for everything you do, including darks. The temperature is coded into the filename. Then you can reuse the darks instead of reshooting them every session.



#7 alphatripleplus

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Posted 17 September 2021 - 07:10 AM

Definitely get the cooled camera for long exposure AP. The thermal noise associated with a long total exposure depends on the thermal signal (i.e. dark current) before dark calibration. You'll notice that thermal noise increases dramatically with temperature, and makes a noticeable contribution as total exposure increases. Unfortunately, adding lots of short sub-exposures doesn't help, as the thermal noise accumulates when stacking short subs to make a long total exposure.



#8 Iones

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Posted 17 September 2021 - 09:24 AM

Definitely get the cooled camera for long exposure AP. The thermal noise associated with a long total exposure depends on the thermal signal (i.e. dark current) before dark calibration. You'll notice that thermal noise increases dramatically with temperature, and makes a noticeable contribution as total exposure increases. Unfortunately, adding lots of short sub-exposures doesn't help, as the thermal noise accumulates when stacking short subs to make a long total exposure.

I did not know about that ! Thank you very much for the information.


Edited by Iones, 17 September 2021 - 09:25 AM.


#9 Deimos20

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Posted 17 September 2021 - 12:35 PM

I recently faced a similar dilemma and chose the uncooled version.  You didn't specify in your post the sky conditions where you will do most of your observing. My backyard is Bortle 7-8 on a good night, so I decided that given the light pollution, my exposures were all going to be short because the

sky glow would overwhelm my sensor long before any amp glow. Right now I also use it mainly for EAA. For any AP sessions It does require as mentioned above, new darks every session to take into account the temp differences along with flats, so you would need to account for that additional time. Also, I do notice more hot pixels during the hotter evenings. Do I regret not getting the uncooled version? Well the $300 saved went to other goodies to get me started, so no, given my current skill level and available time. If my skies were relatively dark, then I would have gone to the cooled version first. Regardless what version you ultimately decide, I believe you will be happy with the 294mc

As for filters, the uncooled version does come with a screw in adapter that allows you to add 1.25 filters just before the protect window and they work just fine.



#10 jgraham

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Posted 17 September 2021 - 12:46 PM

For deepsky I would highly recommend the Pro if it were within your budget. If it is outside of your budget then the non-Pro is worth considering.
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#11 Iones

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Posted 17 September 2021 - 02:37 PM

I recently faced a similar dilemma and chose the uncooled version.  You didn't specify in your post the sky conditions where you will do most of your observing. My backyard is Bortle 7-8 on a good night, so I decided that given the light pollution, my exposures were all going to be short because the

sky glow would overwhelm my sensor long before any amp glow. Right now I also use it mainly for EAA. For any AP sessions It does require as mentioned above, new darks every session to take into account the temp differences along with flats, so you would need to account for that additional time. Also, I do notice more hot pixels during the hotter evenings. Do I regret not getting the uncooled version? Well the $300 saved went to other goodies to get me started, so no, given my current skill level and available time. If my skies were relatively dark, then I would have gone to the cooled version first. Regardless what version you ultimately decide, I believe you will be happy with the 294mc

As for filters, the uncooled version does come with a screw in adapter that allows you to add 1.25 filters just before the protect window and they work just fine.

The sky condition is a good point. I live in a bortle 9 sky, but have access to a bortle 4 area. However, my understanding was that with a good filter like an L-extreme, one could ignore light pollution. 

 

Also thank you very much for confirming that 1.25 inch filters work well. This is definitely a big budgetary factor to take into account.



#12 alphatripleplus

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Posted 17 September 2021 - 02:45 PM

I do EAA with an uncooled ASI290MM mini camera and usually don't bother using it on summer evenings when the sensor temperature is in the 26C-30C range or above, particularly if  I am using a H-alpha filter.  The thermal noise on those evenings, even after subtracting temperature matched darks, will easily overwhelm  sky noise (with a H-alpha filter) and read noise, giving a very grainy background.


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