Is a cooled camera required for short exposure imaging

[Elp]

Just thought I'd ask the question as I will try this soon. I have a 224mc which I've tried previously with decent results though it struggled over 60s with major sensor glow/high read noise but I'm looking to do nebulae so the sensor size needs to be much bigger and am wondering if I can get away with a non cooled version. I already have a 183mm pro so know the benefits of mono and cooling. Exposure range will be up to 30s, looking for a OSC or mono zwo recommendation as I want it to be a lighter camera.

Edited June 29, 2022 by Elp

[gilesco]

I'm just going to recommend a cooled version, there's lots of reports that cooling is not necessary for the results, especially with some of the newer sensors out there, but bear this in mind:

When you start imaging the ambient temperature might be around 12 deg.

Half way through the night the ambient temperature might have dropped to 6 deg.

I notice a difference in the exposures taken uncooled as the sensor temperature changes through the night.

I only cool to around 10 to 20 less than the ambient temperature, not necessarily for the cooling, but for the temperature to be regulated throughout the night.

[Adam J]

35 minutes ago, Elp said:

Just thought I'd ask the question as I will try this soon. I have a 224mc which I've tried previously with decent results though it struggled over 60s with major sensor glow/high read noise but I'm looking to do nebulae so the sensor size needs to be much bigger and am wondering if I can get away with a non cooled version. I already have a 183mm pro so know the benefits of mono and cooling. Exposure range will be up to 30s, looking for a OSC or mono zwo recommendation as I want it to be a lighter camera.

I know @PadrePeace has done DSO work with the 224mc but on galaxies. I would think some bright planetary nebula might work well too. But as for that vast majority of larger emission nebula then the sensor is just too small and I would not think that it would do nearly as well in Narrow Band as it manages in RGB.

There is the Player One Neptune camera based on the IMX533 that would work will for uncooled DSO imaging and has a much larger sensor than the 226. 

My current position is that if you can afford cooling get a cooled camera, if you really cant or dont want it for some other reason then what you need to look for are sensors with no amp glow and low dark current, most of the IMX5xx series fit into this group. 

Adam 

Edited June 29, 2022 by Adam J

[Adam J]

double post, admin remove

Edited June 29, 2022 by Adam J

[Elp]

The new zwo cameras seem interesting, esp the 432mm (prob too low a resolution) and the 585mc, it has to be zwo as it'll be paired with an Asiair.

[Adam J]

26 minutes ago, Elp said:

The new zwo cameras seem interesting, esp the 432mm (prob too low a resolution) and the 585mc, it has to be zwo as it'll be paired with an Asiair.

I would be more interested in the mono 585mm for DSO imaging with a 100 - 400mm focal length scope as the 2.9um pixels leave room for binning at the longer focal lengths while still having a useful FOV.

Should be really good for galaxy imaging too for longer focal lengths 600mm+ and you could use DSO lucky imaging for even longer focal lenghts. 

Adam 

[AstroMuni]

40 minutes ago, Adam J said:

I would think some bright planetary nebula might work well too.

It absolutely does a fantastic job with those. I havent managed to put in as many hours as Padrepeace but even with the few hours that I got the images have come out quite beautifully. A few of them are in my signature link.

[CCD-Freak]

The new cameras are getting very good......I forgot to turn on the cooling of my ASI-2600MCP and shot this image of NGC7023 at +19.5 C. 

4 hours of 3 minutes subs dithered every 5th image captured and processed with Astroart 8. 

I am thinking of getting the ASI-432MM for imaging galaxies with longer FL scopes and I have an ASI-482MC that I plan to give a go with next time I am out imaging at the dark site.

 

 

Edited July 17, 2022 by CCD-Freak

[Elp]

 

3 hours ago, CCD-Freak said:

shot this image of NGC7023

That's a great image, I've done 20+ hours on this from a bortle 7 and couldn't get the dust out of the image.

[Adam J]

4 hours ago, CCD-Freak said:

The new cameras are getting very good......I forgot to turn on the cooling of my ASI-2600MCP and shot this image of NGC7023 at +19.5 C. 

4 hours of 3 minutes subs dithered every 5th image captured and processed with Astroart 8. 

I am thinking of getting the ASI-432MM for imaging galaxies with longer FL scopes and I have an ASI-482MC that I plan to give a go with next time I am out imaging at the dark site.

 

 

Depends on actual ambient temperature. But I would say that in the majority of cases if you exposing less than 60s at less than 20c you don't need cooling. 

[CCD-Freak]

I was shooting 180 second subs and I did not notice the cooler was off until I already had most of the images saved.  They looked pretty good on the screen so I let it finish and I stacked it to see how it would come out.   My site is dark (Bortle 1-2) so that helped a lot but I was amazed that the image turned out as well as it did.  I have done this twice and was surprised that the images were salvageable.  

I am planning to do some imaging with my non cooled ASI-482MC to see how it works for galaxy imaging.  I plan to shoot 60 or 120 second subs dithering frequently and I plan to get at least 120 subs.  It should be an interesting experiment especially since it is freaking HOT here right now.  (24C for the low temperature)

This screen grab image of M83 was a 180 second single exposure with the ASI-482MC binned 2x2 mono and NO dark and it is fairly clean so it gives me hope.  (^8

This M78 image was shot at 22C with the ASI-2600MCP

 

[Elp]

Pretty amazing, the only other one is have is a 224mc and that amp glows pretty bad on long exposure.

[PadrePeace]

Uncooled 224MC Pinwheel. Check it out: 

 

And uncooled Needle Galaxy:

 

[Elp]

I've seen your work, you've achieved some excellent results.

[PadrePeace]

56 minutes ago, Elp said:

I've seen your work, you've achieved some excellent results.

Thanks for the compliment but my reason for flagging them is it covers off short exposures for uncooled cameras, although I’m not sure the camera would have got much warmer with longer exposure as the gaps between images at 30s exp was virtually nothing so not a lot of cooling going on!

As for amp glow a good master dark frame will always fix that although one clearly needs to invest time in shooting and stacking long exp darks which not everyone wants to do. 

[Elp]

Ive done a DSO test on it with m101 previously, it turned out okay even though it was a short test. I've also been running some tests recently and its operating temperature tends to be around 32 Deg C in an 27 Deg C ambient environment so looking into the cooling effect next. Calibration is essential, the point about amp glow is that I don't think the camera was designed with DSO in mind but it doesn't stop owners from trying as I want to use it for planetary nebulae or small galaxies, it's amp glow is certainly on par or much worse than my 183mm pro during long exposures and I think dithering more often will be required with the 224 (I don't usually have to dither with the 183).

 

[bomberbaz]

This is my effort from uncooled although ti was from the starting point of my learning curve. The OP may remember it from the AZ Gti thread.

NGC7380 (Wizard) - ZWO 224mc - 200 x 10sec and 10 x 30sec starting at an ambient of 18C dropping to about 11C, working camera at average 18C, it cooled as the night went on. It's quite red I know. 

Only a rough effort. However I think 30 seconds is a good starting exposure length for this camera, gain trial and error. 

Going forward I shall reserve this camera for colder nights and smaller targets. I will also make use of a USB smartphone cooler going forward, the one I have lowers the temp of camera by around 6 -10 degree C, depending on ambient. The warmer it is, the more it cools. (I forgot it on the night I grabbed the data from the attached).

Anyway, the 224MC (uncooled) still has a place in my bag.

[Elp]

It's achieved something at such a short integration time, a few more hours and it'll reveal itself for sure.

[AstroMuni]

11 hours ago, bomberbaz said:

Anyway, the 224MC (uncooled) still has a place in my bag.

I'll second that. Its a great camera, albeit with a small sensor.

[PadrePeace]

22 hours ago, bomberbaz said:

This is my effort from uncooled although ti was from the starting point of my learning curve. The OP may remember it from the AZ Gti thread.

NGC7380 (Wizard) - ZWO 224mc - 200 x 10sec and 10 x 30sec starting at an ambient of 18C dropping to about 11C, working camera at average 18C, it cooled as the night went on. It's quite red I know. 

Only a rough effort. However I think 30 seconds is a good starting exposure length for this camera, gain trial and error. 

Going forward I shall reserve this camera for colder nights and smaller targets. I will also make use of a USB smartphone cooler going forward, the one I have lowers the temp of camera by around 6 -10 degree C, depending on ambient. The warmer it is, the more it cools. (I forgot it on the night I grabbed the data from the attached).

Anyway, the 224MC (uncooled) still has a place in my bag.

Which phone cooler are you using?

[bomberbaz]

Just thought I would add some no cooled files from different exposure times, as mentioned it was at the start of my own learning curve and up until now I had not done a process of comparable files using a measureable process.

Anyway, did it earlier, basic processing using siril. Both pictures very noisy as only 5 minutes data each.  10x30 seconds and 30x10 seconds.

Going off these results I think next decent nights worth of imaging I will try to obtain some decent amounts of (semi cooled) data on a bright-ish object such as the owl/dumbbell to run a better comparison but run at longer times. 30 seconds and 60 seconds with a total at minimum of 30 minutes minimum but ideally 1 hour I think. 

I am only using a 50mm scope to grab data so as results stand they are inconclusive. 

10 x 30

30 x 10

[Elp]

The 30s one look like better signal if that's the top image, further time will undoubtedly provide a better test.

[bomberbaz]

On 28/07/2022 at 09:23, Elp said:

The 30s one look like better signal if that's the top image, further time will undoubtedly provide a better test.

top image is indeed at 30 seconds, stronger signal for sure but more noise. 

As you say, more time (data) will hopefully give a more conclusive result. 

[Elp]

I tried this, think it worked out well:

 

[Ian McCallum]

On 18/07/2022 at 15:38, PadrePeace said:

Thanks for the compliment but my reason for flagging them is it covers off short exposures for uncooled cameras, although I’m not sure the camera would have got much warmer with longer exposure as the gaps between images at 30s exp was virtually nothing so not a lot of cooling going on!

As for amp glow a good master dark frame will always fix that although one clearly needs to invest time in shooting and stacking long exp darks which not everyone wants to do. 

Can I ask what the pause or resting period do you use between your 30 second exposures, please?