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

Updated version of the ASI183MC

  • Please log in to reply
42 replies to this topic

#1 gfunkernaught

gfunkernaught

    Ranger 4

  • *****
  • topic starter
  • Posts: 368
  • Joined: 10 Feb 2020
  • Loc: New York

Posted 02 October 2022 - 10:20 AM

I'm looking for a cooled camera like this with small pixels but that doesn't suffer from amp glow. I currently use the asi2600mc pro and love it, but wanted to image smaller targets with a little more detail without increasing focal length. Is there a camera out there that is of the same quality as the asi2600 but small pixels of the 183?

#2 imtl

imtl

    Fly Me to the Moon

  • *****
  • Moderators
  • Posts: 6,422
  • Joined: 07 Jun 2016
  • Loc: Down in a hole

Posted 02 October 2022 - 10:35 AM

I'm looking for a cooled camera like this with small pixels but that doesn't suffer from amp glow. I currently use the asi2600mc pro and love it, but wanted to image smaller targets with a little more detail without increasing focal length. Is there a camera out there that is of the same quality as the asi2600 but small pixels of the 183?


No.
  • Baron von Smoogle likes this

#3 MarMax

MarMax

    Gemini

  • *****
  • Posts: 3,073
  • Joined: 27 May 2020
  • Loc: SoCal

Posted 02 October 2022 - 10:36 AM

Good question and I researched this a while back and the only thing I came up with is the Orion Starshoot G21 (IMX269) with 3.3 um pixels. I really like the 183MC and wish there was a 4/3 sensor with at least 2.9 um pixels.



#4 DeepSky Di

DeepSky Di

    Vanguard

  • -----
  • Moderators
  • Posts: 2,087
  • Joined: 15 Aug 2020

Posted 02 October 2022 - 10:44 AM

The 533mc is the smaller sensor version of the 2600 but has larger pixels than the 183mc: https://astronomy-im...533mc-pro-color



#5 james7ca

james7ca

    Voyager 1

  • *****
  • Posts: 11,357
  • Joined: 21 May 2011
  • Loc: San Diego, CA

Posted 02 October 2022 - 10:45 AM

AFAIK, the only camera without amp glow that has a pixel size equal to or below that of the ASI183MC is Sony's 2um pixel-size color IMX678. But, it's only available as an uncooled planetary camera and the sensor size is only about one half that of the IMX183 (meaning only one quarter of the area and pixel count).

 

However, I kind of expect that within the next year or two that there will be a new version of the IMX183 (the IMX683?) that will use 2um pixels and which should also have no amp glow. Unfortunately, I also predict that it won't come in a mono version, only one-shot-color.

 

That said, I have one of the ZWO ASI678MC cameras and it produces a very clean, low noise image even without cooling and it does NOT have any amp glow until you get into the five to ten minutes exposure range and even then it is very mild, appearing only as a slight (narrow) brightening along the very edges of the frame.

 

In fact, cooling may not be completely necessary, although some form of temperature regulation would be nice to help with the calibration subs.

 

The other issue is that the cameras that are based upon recent surveillance sensors (like the IMX678) tend to have less accurate color reproduction since they have a much broader overlap in sensitivity between their green and red pixels. I GUESS this is because Sony wants these sensors to do double duty in both one-shot-color and the near IR. You can in fact use the ASI678MC as a mono camera in the near IR (filtered at around 850nm), just as with the ASI462MC and a few other recent planetary cameras from both ZWO and QSI QHY.


Edited by james7ca, 02 October 2022 - 11:47 AM.


#6 gfunkernaught

gfunkernaught

    Ranger 4

  • *****
  • topic starter
  • Posts: 368
  • Joined: 10 Feb 2020
  • Loc: New York

Posted 02 October 2022 - 11:32 AM

The 533mc is the smaller sensor version of the 2600 but has larger pixels than the 183mc: https://astronomy-im...533mc-pro-color

Right, the 533 is a cropped 2600, basically.

#7 gfunkernaught

gfunkernaught

    Ranger 4

  • *****
  • topic starter
  • Posts: 368
  • Joined: 10 Feb 2020
  • Loc: New York

Posted 02 October 2022 - 11:33 AM

AFAIK, the only camera without amp glow that has a pixel size equal to or below that of the ASI183MC is Sony's 2um pixel-size color IMX678. But, it's only available as an uncooled planetary camera and the sensor size is only about one half that of the IMX183 (meaning only one quarter of the area and pixel count).

However, I kind of expect that within the next year or two that there will be a new version of the IMX183 (the IMX683?) that will use 2um pixels and which should also have no amp glow. Unfortunately, I also predict that it won't come in a mono version, only one-shot-color.

That said, I have one of the ZWO ASI678MC cameras and it produces a very clean, low noise image even without cooling and it does NOT have any amp glow until you get into the five to ten minutes exposure range and even then it is very mild, appearing only as a slight (narrow) brightening along the very edges of the frame.

In fact, cooling may not be completely necessary, although some form of temperature regulation would be nice to help with the calibration subs.

The other issue is that the cameras that are based upon recent surveillance sensors (like the IMX678) tend to have less accurate color reproduction since they have a much broader overlap in sensitivity between their green and red pixels. I GUESS this is because Sony wants these sensors to do double duty in both one-shot-color and the near IR. You can in fact use the ASI678MC as a mono camera in the near IR (filtered at around 850nm), just as with the ASI462MC and a few other recent planetary cameras from both ZWO and QSI.


I guess we'll have to wait. I really like the 2600, solid camera, even for smaller objects at 1450mm, it produces good detail.

#8 Tapio

Tapio

    Fly Me to the Moon

  • -----
  • Posts: 7,285
  • Joined: 24 Sep 2006
  • Loc: Tampere, Finland

Posted 02 October 2022 - 12:02 PM

Why is the amp glow such a deal breaker?
  • dswtan likes this

#9 gfunkernaught

gfunkernaught

    Ranger 4

  • *****
  • topic starter
  • Posts: 368
  • Joined: 10 Feb 2020
  • Loc: New York

Posted 02 October 2022 - 12:16 PM

Why is the amp glow such a deal breaker?

Well for me it is because I image at f/7 so longer exposure times are more useful to me.  Plus amp glow can be tricky to remove based upon what I've read.  Darks have to be the same exact temp as lights, aside from gain and exp time.  I use a dark library with a small range of temps and also use dark optimization in DSS.  



#10 Tapio

Tapio

    Fly Me to the Moon

  • -----
  • Posts: 7,285
  • Joined: 24 Sep 2006
  • Loc: Tampere, Finland

Posted 02 October 2022 - 12:40 PM

In essence if you do calibration right amp glow is not a problem.
  • Baron von Smoogle likes this

#11 jonnybravo0311

jonnybravo0311

    Skylab

  • *****
  • Moderators
  • Posts: 4,103
  • Joined: 05 Nov 2020
  • Loc: NJ, US

Posted 02 October 2022 - 01:07 PM

Well for me it is because I image at f/7 so longer exposure times are more useful to me.  Plus amp glow can be tricky to remove based upon what I've read.  Darks have to be the same exact temp as lights, aside from gain and exp time.  I use a dark library with a small range of temps and also use dark optimization in DSS.  

Darks need to be taken at the same temperature, gain and exposure time. Dark optimization is not really useful for CMOS sensors as they don't behave in quite the same way CCD sensors do. Dark libraries are extremely easy to take and maintain, too. If that's your biggest drawback, then cross it off the list :).

 

What scope are you using with the 2600?


  • jdupton likes this

#12 james7ca

james7ca

    Voyager 1

  • *****
  • Posts: 11,357
  • Joined: 21 May 2011
  • Loc: San Diego, CA

Posted 02 October 2022 - 01:56 PM

I agree with Jonnybravo's recommendations, but one of the reasons why dark field optimization doesn't work with CMOS cameras is because many of these types of cameras have amp glow. So, remove the amp glow and you may have an easier time with your calibration files. Plus, without amp glow and under moderate or worse light pollution you may be able to swamp the camera's read noise even with very short exposures and in that case you might still get decent results even without dark field calibration (at least for casual work, but not if you want top drawer results).



#13 gfunkernaught

gfunkernaught

    Ranger 4

  • *****
  • topic starter
  • Posts: 368
  • Joined: 10 Feb 2020
  • Loc: New York

Posted 02 October 2022 - 04:20 PM

My two cameras, the asi2600mc and canon eos ra, have zero amp glow, this allowing me to use a static dark library and dark optimization. Check out my astro bin, I believe I'm getting excellent results.
https://www.astrobin.../gfunkernaught/

#14 gfunkernaught

gfunkernaught

    Ranger 4

  • *****
  • topic starter
  • Posts: 368
  • Joined: 10 Feb 2020
  • Loc: New York

Posted 02 October 2022 - 04:20 PM

Darks need to be taken at the same temperature, gain and exposure time. Dark optimization is not really useful for CMOS sensors as they don't behave in quite the same way CCD sensors do. Dark libraries are extremely easy to take and maintain, too. If that's your biggest drawback, then cross it off the list :).

What scope are you using with the 2600?


Celestron 8SE.

#15 xonefs

xonefs

    Viking 1

  • *****
  • Posts: 699
  • Joined: 23 Aug 2020

Posted 02 October 2022 - 06:12 PM

if you are seeing limited which is likely unless you are less than 500-600mm focal length than getting a smaller pixel cam is not going to give you better detail

Edit- on a nextstar 8se theres almost no way going to smaller pixels will give you better detail. You are certainly already oversampled on the 2600 and should be binning at least 2x which will improve snr and probably make smaller targets look better. Possibly even more… looks like you could also improve collimation and guiding. Smaller pixels won’t help.

Edited by xonefs, 02 October 2022 - 06:19 PM.


#16 jonnybravo0311

jonnybravo0311

    Skylab

  • *****
  • Moderators
  • Posts: 4,103
  • Joined: 05 Nov 2020
  • Loc: NJ, US

Posted 02 October 2022 - 07:34 PM

Celestron 8SE.

Is that the same scope you'd use with the 183 (or if it existed, the no amp-glow version) or do you have another scope in mind for the smaller pixel camera? I notice a couple of your images on AB list an ED80. That scope would pair well with the 183... though it's already pretty nicely matched up with your 2600.

 

Assuming you're using the 0.63x with the 8SE, you're still a bit over-sampled with the 2600. If you're running that scope natively at f/10, you're well over-sampled as xonefs wrote.



#17 gfunkernaught

gfunkernaught

    Ranger 4

  • *****
  • topic starter
  • Posts: 368
  • Joined: 10 Feb 2020
  • Loc: New York

Posted 02 October 2022 - 09:20 PM

if you are seeing limited which is likely unless you are less than 500-600mm focal length than getting a smaller pixel cam is not going to give you better detail

Edit- on a nextstar 8se theres almost no way going to smaller pixels will give you better detail. You are certainly already oversampled on the 2600 and should be binning at least 2x which will improve snr and probably make smaller targets look better. Possibly even more… looks like you could also improve collimation and guiding. Smaller pixels won’t help.

Really?  I still have a raw I took with my friend's 183 using the Starizona SCT Corrector IV, it does look slightly more detailed than the 2600.  I can't get the image up at the moment, NAS is offline.  I don't see any collimation issues, OTA is well collimated for those images, not sure which image you're referring to.  I guide .55" most of the time.



#18 xonefs

xonefs

    Viking 1

  • *****
  • Posts: 699
  • Joined: 23 Aug 2020

Posted 02 October 2022 - 11:05 PM

I'm pretty certain if you posted any of those images with the 2600 and corrector I could bin them 2-3x without losing detail. I thought I had saw some odd donut shaped stars on some in corners. 

 

for reference I use a 2600mm with a sharpstar sca260 at 1300mm. My seeing is very good, and the optics are probably a step above the 8se. I resample between 2-3x in post without losing real detail. To know for sure you can resample until small non overexposed stars don't take up more than a 2x2 pixel block or so. resolution above that doesn't give you real resolution benefit it just reduces SNR. 


Edited by xonefs, 02 October 2022 - 11:10 PM.


#19 gfunkernaught

gfunkernaught

    Ranger 4

  • *****
  • topic starter
  • Posts: 368
  • Joined: 10 Feb 2020
  • Loc: New York

Posted 03 October 2022 - 07:31 AM

I'm pretty certain if you posted any of those images with the 2600 and corrector I could bin them 2-3x without losing detail. I thought I had saw some odd donut shaped stars on some in corners.

for reference I use a 2600mm with a sharpstar sca260 at 1300mm. My seeing is very good, and the optics are probably a step above the 8se. I resample between 2-3x in post without losing real detail. To know for sure you can resample until small non overexposed stars don't take up more than a 2x2 pixel block or so. resolution above that doesn't give you real resolution benefit it just reduces SNR.

If you're looking at the far corners, then those stars will never be correct on my system, especially those images that I didn't crop. The 2600 sensor is slightly larger than the corrected image circle of the starizona corrector. I haven't tried binning yet, maybe I'll give it a shot. As far as bloated stars, I use gain 300 so I don't have to process twice or 3x the number of lights. Also, depending on the target, I don't mind saturated stars, it's an art thing.

But all in all, smaller pixels would mean I'd have to guide at .3" vs .55" which is quite a challenge even for the eq6r and my typical seeing conditions. But I do travel with my rig, so if seeing is good wherever I go, it'd be nice to be prepared.

Edited by gfunkernaught, 03 October 2022 - 07:33 AM.


#20 jonnybravo0311

jonnybravo0311

    Skylab

  • *****
  • Moderators
  • Posts: 4,103
  • Joined: 05 Nov 2020
  • Loc: NJ, US

Posted 03 October 2022 - 09:04 AM

I looked at the specs of that Starizona SCT corrector. According to the description, with the 8" SCT, it's f/7.1. Starizona claims this is because the 8" is closer to f/11 than f/10 and the shorter back focus distance. The only scope they list it actually getting you to f/6.3 is the C11. The relevant part of that description, though, is the claimed 27mm image circle. The 2600 has a sensor diagonal of about 28.5mm. 

 

Anyway, as I wrote in my previous reply, even with that reducer you're over-sampled already with the 2600. You're about 0.6"/px scale. If you strapped a 183 onto that rig, you're going to be down around 0.35"/px. Even more over-sampled. Guiding/tracking at, or under, that value is going to be a challenge.

 

Also, you wrote something I am not quite following. What do you mean by this:

 

As far as bloated stars, I use gain 300 so I don't have to process twice or 3x the number of lights.

 

 

Why? You're killing your dynamic range and well capacity by doing this. Is your thinking behind this strategy "If I increase my gain to 300, I can take a 120 second exposure that has more detail than if I took that same 120 second exposure at a gain of 0. Thus, I can take fewer high-gain subs to get the same information I would get by taking many low-gain subs. Sure, I might blow out stars, but I don't care."? 



#21 gfunkernaught

gfunkernaught

    Ranger 4

  • *****
  • topic starter
  • Posts: 368
  • Joined: 10 Feb 2020
  • Loc: New York

Posted 03 October 2022 - 09:18 AM

I looked at the specs of that Starizona SCT corrector. According to the description, with the 8" SCT, it's f/7.1. Starizona claims this is because the 8" is closer to f/11 than f/10 and the shorter back focus distance. The only scope they list it actually getting you to f/6.3 is the C11. The relevant part of that description, though, is the claimed 27mm image circle. The 2600 has a sensor diagonal of about 28.5mm.

Anyway, as I wrote in my previous reply, even with that reducer you're over-sampled already with the 2600. You're about 0.6"/px scale. If you strapped a 183 onto that rig, you're going to be down around 0.35"/px. Even more over-sampled. Guiding/tracking at, or under, that value is going to be a challenge.

Also, you wrote something I am not quite following. What do you mean by this:


Why? You're killing your dynamic range and well capacity by doing this. Is your thinking behind this strategy "If I increase my gain to 300, I can take a 120 second exposure that has more detail than if I took that same 120 second exposure at a gain of 0. Thus, I can take fewer high-gain subs to get the same information I would get by taking many low-gain subs. Sure, I might blow out stars, but I don't care."?

If you're using the ccd calculator from astronomy.tools, according to "good seeing" I'm slightly oversampled, but there are times where I can get better seeing, just depends on weather and/or location. The gain question is not about detail but processing time and load. I use the L-Enhancr and L-Pro filters and don't want to process 300x150sec gain 0, I rather do 150x300sec gain 300, as a crude example. I personally don't see an issue with my processing routine, and I try my best NOT to pixel-peep. Pixel peeping is a black hole and takes the fun out of the hobby, for me at least. I don't do this for a living so if a star is taking up too many pixels it won't hurt me.

We went off topic here. Bottom line is as stated using a 183 with my setup will require .3" or so guiding which is the challenge I might be willing to accept. If I achieve this, then I probably will get a bit more detail, if seeing allows. Fun is paramount here, not pixel peeping.

Clear skies!

#22 xonefs

xonefs

    Viking 1

  • *****
  • Posts: 699
  • Joined: 23 Aug 2020

Posted 03 October 2022 - 01:59 PM

You are pretty much describing pixel peeping to inch out more detail, which really isn’t possible with that setup which is the point

It has nothing to do with how well you can guide even with perfect guiding your seeing is not good enough for those scales

Forget calculators you can tell by looking at the images and smeared detail that you are already beyond sampling limits for your seeing and optics

Edited by xonefs, 03 October 2022 - 02:01 PM.


#23 gfunkernaught

gfunkernaught

    Ranger 4

  • *****
  • topic starter
  • Posts: 368
  • Joined: 10 Feb 2020
  • Loc: New York

Posted 03 October 2022 - 02:21 PM

I travel with my gear, and I don't want a massive collection of OTAs and gear, again I do this for fun, and I don't zoom in down to the pixel.  Better processing techniques can also yield more detail.  Not sure how we got from a better version of the 183 to analysis and critique.  Oh wait did I get pulled over by the refractor police?



#24 jonnybravo0311

jonnybravo0311

    Skylab

  • *****
  • Moderators
  • Posts: 4,103
  • Joined: 05 Nov 2020
  • Loc: NJ, US

Posted 03 October 2022 - 02:49 PM

Ultimately, the answer to the question in the original post was given by Eyal in the second post: no such camera exists. James speculated about some upcoming possibilities (like maybe a 683 with 2.0µm pixels like in the new 678).

 

Unless someone knows about new hardware, I think this thread has run its course :).


  • gfunkernaught likes this

#25 charles.tremblay.darveau

charles.tremblay.darveau

    Messenger

  • *****
  • Posts: 431
  • Joined: 16 Oct 2020

Posted 03 October 2022 - 02:58 PM

Good question and I researched this a while back and the only thing I came up with is the Orion Starshoot G21 (IMX269) with 3.3 um pixels. I really like the 183MC and wish there was a 4/3 sensor with at least 2.9 um pixels.

The 294mm in Bin 1 has 2.3 microns pixels.




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