CMOS camera recomendations

[Rattler]

Hey guys. I'm looking to upgrade from a DSLR to a CMOS camera to use with my Explore Scientific ED80. I'm currently considering the Altair Astro 183c Pro, 183c TEC or ZWO ASI183C. Possibly one of the QHY cameras too. Any advice would be appreciated. Cheers.

[Kaliska]

Personally, I stepped up from the DSLR (700D) to mono CMOS. I concidered going colour chip, but I'm glad i went mono, the detail is quite something and you dont have to always wait for the moon to dissapear with your narrow band filters. I will though cost a bit more money and you have to get a filter wheel.

[Adam J]

2 hours ago, Rattler said:

Hey guys. I'm looking to upgrade from a DSLR to a CMOS camera to use with my Explore Scientific ED80. I'm currently considering the Altair Astro 183c Pro, 183c TEC or ZWO ASI183C. Possibly one of the QHY cameras too. Any advice would be appreciated. Cheers.

Don't consider anything that is not set point cooled perticually with the 183 which requires good calibration. Also I recommend that you get the mono version. The Altair Astro 183mono TEC or the ASI183mm pro would be my choices. If you insist on OSC then out of your list I would get the Altair Astro 183c TEC as it looks a little better made than the ASI not that the ASI is a poor camera. 

[newbie alert]

Qhy version has the Tec cooling too..

Obviously the sensor is the same but are they all the same camera spec wise..cooled version obviously 

[Rattler]

I totally understand the advantages of mono. My concern with mono is my limited time out imaging. I have to travel to image as I can't do it from my flat due to various reasons. 

[AngryDonkey]

Mono is more complex but it is NOT slower than OSC. If you do a search comparing the two on this forum, most argue it is actually quicker. The question is more do you want an easier solution with less hassle or accept the added complexity and get a more capable system.

[Rattler]

5 hours ago, AngryDonkey said:

Mono is more complex but it is NOT slower than OSC. If you do a search comparing the two on this forum, most argue it is actually quicker. The question is more do you want an easier solution with less hassle or accept the added complexity and get a more capable system.

I recently captured 90 minutes of data on M31 with my DSLR and created a nice image. Surely I couldn't get a good image in the equivalent time using mono?

[AngryDonkey]

Why not?

[Rattler]

58 minutes ago, AngryDonkey said:

Why not?

Would it not need longer than say 30 minutes per channel?

[Adam J]

6 hours ago, Rattler said:

Would it not need longer than say 30 minutes per channel?

Most people would give it longer. But the point is that using 30mins per channel it will surpass your dslr image. Use 2 minutes subs for 15 frames per channel. Bring luminance in at another 30mins and it will take it to a whole new level. Lots of people don't pay more for mono and filters just because they want to make there life difficult. 

[Rattler]

Hmm yeah I'm considering mono now. In that price range would you guys still recommend the Altair Astro 183c TEC?

[DaveS]

TBH I've had no end of problems with amp-glow on my ASI183MM Pro. The only time I got rid of it was sigma stacking subs with a meridian flip, the sigma rutine treatd it as an artifact and got rid of it. I've had much better results with the ASI1600MMC.

My next camera is likely to be CCD.

[Adam J]

5 hours ago, DaveS said:

TBH I've had no end of problems with amp-glow on my ASI183MM Pro. The only time I got rid of it was sigma stacking subs with a meridian flip, the sigma rutine treatd it as an artifact and got rid of it. I've had much better results with the ASI1600MMC.

My next camera is likely to be CCD.

I have a few questions for you.

1) What program are you using to stack, it has been noticed recently that people using nebulocity are unable to fully calibrate the 183m chip.

2) Irrespective of the stacking program you are using have you disabled dark frame optimization / scaling? If not then a CMOS chip will not correctly calibrate.

3) What gain are you using on the 183m, high gains are not recommended with the chip and it works better with lower gains an moderate exposure lengths. Lots of people recommend gain 57 and 5 min exposures.

4) When did you take your dark frames? You cant expect dark frames taken with a CMOS in winter to work in summer. They have to be taken at an ambient temperature in the near to that of the light frames. So +- 10c would be a good starting point. Hence you need to record your dark frame ambient temperature. Ie if you take your darks at 20c ambient dont expect them to work with lights taken at 0c ambient like with a ccd.

Adam

[DaveS]

Stacking and callibration in AstroArt 5

Will check if Dark Frame Optimisation was checked

Gain was at minimum, using the "max DR" setting.

Dark frames taken at the same set-point as the lights, -20c

[Adam J]

14 hours ago, DaveS said:

Stacking and callibration in AstroArt 5

Will check if Dark Frame Optimisation was checked

Gain was at minimum, using the "max DR" setting.

Dark frames taken at the same set-point as the lights, -20c

Actually gain 0 could cause you issues too, try 57.

With the dark frames its more about keeping taking the darks at a similar ambient temperature irrespective of set point. It does not have to be identical but you will need summer and winter darks.

Try -10c for the set point, thats actually the temperature recommended by ASI as you dont get any real improvement with thermal noise below -10c and you are increasing the thermal delta which can result in calibration problems with respect to ambient temperature variation. At least in accordance with what people who are getting good results on cloudy nights are saying about the camera.

AstroArt 5 was not mentioned, some have Dark Frame scaling inbuilt and no option to disable. It might be worth stacking in DSS with optimization disabled to see if it improves your calibration results..

I use Astro Pixel Processor and they had an update to improves CMOS calibration perpetually with the 183..

I guess you have a few things worth a try though. I think the chip is workable as there are some cracking shots starting to populate Astrobin and I dont see amp glow / starburst effect in them.

 

[DaveS]

Thanks Adam.

I'll check out the ASCOM settings, see what gain options I have.

The lights I was taking were during a warm summer night, about 20deg I should think. Set point was -20 but the camera barely reached it. When I came to take the darks it was still a hot day so put the camera in the 'fridge to get the temp down. Will try again this week when I have a similar daytime temp.

TBH if the wretched thing is this finniky then I wonder if it's worth it.

[Yawning Angel]

On ‎18‎/‎08‎/‎2018 at 09:20, Rattler said:

I recently captured 90 minutes of data on M31 with my DSLR and created a nice image. Surely I couldn't get a good image in the equivalent time using mono?

One thing, and I'm sure you'll have considered this....but the 183 is a smaller sensor than your Canon. Be careful your not hamstringing your target list (I've used the ZWO versions here, just for ease)

[Rattler]

2 hours ago, Yawning Angel said:

One thing, and I'm sure you'll have considered this....but the 183 is a smaller sensor than your Canon. Be careful your not hamstringing your target list (I've used the ZWO versions here, just for ease)

Yeah I had taken this into consideration bud. Think I'd need a reducer aswell.

[Rattler]

Is there anything other than a 183 that would be more suitable?

[DaveS]

I'd be inclined to go with the ASI 1600 MMC Pro. It's a but more, and the pixels are a bit bigger, but I've had fewer amp-glow problems. But it's your money, and your choice.

[Adam J]

43 minutes ago, Rattler said:

Is there anything other than a 183 that would be more suitable?

As above the ASI1600mm pro is another option, but its going to set you back another 270 pounds over the ASI183mm pro.

I am not convinced there are universal calibration issues with the 183 chip that are not solvable by using the correct settings, or it would be evident on images on astrobin. For example I see no calibration issues / amp glow in this image of the day here:

https://www.astrobin.com/360845/0/?nc=all

or here:

https://www.astrobin.com/full/343582/0/

or here:

https://www.astrobin.com/full/337615/0/

or here:

https://www.astrobin.com/full/346935/B/

or here:

https://www.astrobin.com/337365/B/?nc=user

I would be very very very happy to call any of those images mine. Maybe one day lol.

-----

In terms of other options what you may gain in ease of calibration (not convinced there is a real issue) and in a larger sensor area with the ASI1600mm pro must be offset against how annoying you personally find the micro lens diffraction effect that the ASI1600mm pro produces on bright stars. For example:

https://www.cloudynights.com/topic/565014-new-to-narrowband-imaging-question-about-strange-pattern-in-bright-star-halo/

Beyond that you have the second hand market:

Something like this: http://www.astrobuysell.com/uk/propview.php?view=140197

The ATIK 383L+ is a great camer but it requires long exposures to get the best from it (20min +) and you will need 36mm filters with a KAF8300 chip.

Or this: http://www.astrobuysell.com/uk/propview.php?view=140145

Great sensor, very easy to get good results, about the same size as the 183 but does not even require dark frames (apparently) can use 1.25 inch.

Adam

[Rattler]

Thanks for that Adam. Can you use 1.25" with the 183?

[Dragon_Astro]

3 minutes ago, Rattler said:

Thanks for that Adam. Can you use 1.25" with the 183?

I use 1.25" filters with mine, with no vignetting.

[DaveS]

Yes, with very little, if any, vignetting. You can even use them with the 1600 with flats, which you should be taking anyway.

[Dragon_Astro]

I don't know about the other 183 users on here, but my Altair version saves full res files at 40mb EACH.

Annoyingly have to work at 2736 x 1824 to keep the file sizes down, so a good laptop would be a plus. Strangely they recommend using USB 2 for Dso work as it's more stable.