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

Astro camera upgrade recommendations?

  • Please log in to reply
13 replies to this topic

#1 mtc

mtc

    Ranger 4

  • -----
  • topic starter
  • Posts: 383
  • Joined: 04 Apr 2005
  • Loc: Chelmsford, MA

Posted 31 March 2020 - 08:17 AM

I have a 127 Mak-Cass on a Sirius EQ mount. I prefer OSC cameras and live with Bortle 6 skies.

I started with the original Orion Starshoot DSC Cooled camera with a SAC F3/F5 reducer screwed into the nose piece of the camera.

I was pleased with what I could get from it, with my 60-90 second frames. (I never Bin)

When Windows XP retired, so did this camera (which still works nicely, with Windows XP)

Original Starshoot DSC CCD Specs:
  Effective pixels: 752H x 582V (440k pixels)
  Total pixels: 795H x 596V (470k pixels)
  Chip size: 6.00mmH x 4.96mmV
  Pixel size: 6.5umH x 6.25umV

 

I then switched to using my Canon T5i attached to a Celestron F/6.3 Reducer

Effective pixels: 5184H x 3456V )(18M pixels)
Total pixels:
Chip size: 22.3mm x 14.9mm (APS-C)
Pixel size: 4.30umH x 4.30umV

 

I prefer keeping the F6.3 Reducer in place and I believe a cooled OSC astro camera may be more sensitive than my T5i and allow me to capture more data in less time.

I was thinking that either one of these cameras would be a better fit for my imaging train, sky conditions,etc. I do prefer the ASI line since I'm now using the 290mm-mini for my guide camera.

 

ASI294MC-PRO  11.7mp  4.63 um pixels, 4144x2822, backlit, zero amp glow, 4/3" sensor 23.2mm diagonal, readnoise 1.2e, qe 75%, full well 63.7ke, exp 32us-2000s, usb3/usb2

ASI533MC-PRO  9.07mp  3.76 um pixels, 3008x3008, backlit, zero amp glow, 11.31mmx11.31mm sensor, readnoise 1.0e-3.8e, qe >80%, full well 50ke, exp 32us-2000s, usb3

 

Was it the original pixel size (6.25um) that gave me the images I liked? or the fact that it was cooled?

 

I'm not certain which camera would be a better fit for my setup...

 

Thoughts?

 



#2 Joshm1084

Joshm1084

    Explorer 1

  • *****
  • Posts: 60
  • Joined: 02 Nov 2017
  • Loc: Aiken, South Carolina

Posted 31 March 2020 - 08:47 AM

Following this thread as I'm in nearly the exact same boat! I've also been using a 127 Mak-Cass w/ a .63 reducer when doing galaxy work, currently looking to upgrade from a Canon T3i to a cooled astro cam. 

 

The 533 is on my short list of potential cameras. 

 

Hope some experts weigh in smile.gif



#3 bobzeq25

bobzeq25

    Hubble

  • *****
  • Posts: 19,672
  • Joined: 27 Oct 2014

Posted 31 March 2020 - 09:10 AM

You're looking at relatively small details.  Either would be a good choice.  Different people would make it differently, and I'm certainly not going to try to make it for you.

 

Cooling is crucial, it's the main reason to prefer a one shot color astro camera to a DSLR.  The other reason is to get more sensitivity to H alpha.  Then filters like the duo bands that are essentially a compromise between broadband LP filters and narrowband, will work well.  Those are the big deals.

 

QE matters a bit.  The chip size sets the field of view.

 

That's about it.  4.63 versus 3.76 pixels is a trivial difference, as are some of the other numbers.

 

Working on your processing skills will make much more difference than that.  <smile>  This is far from being all about the equipment.


Edited by bobzeq25, 31 March 2020 - 09:18 AM.


#4 dghent

dghent

    Messenger

  • *****
  • Vendors
  • Posts: 445
  • Joined: 10 Jun 2007

Posted 31 March 2020 - 09:25 AM

I would consider the QHY294C or ZWO ASI294MC-Pro. Both use the same and very well-regarded Sony IMX294 sensor, which is a 4/3 format, color, 14bit, backside-illuminated CMOS with 4.63um pixels and ca. 4100x2800, 11.6mp resolution. 

 

This has slightly larger pixel sizes than your existing T5i, which is more in-line with your working focal length in terms of sampling. I would certainly choose it over the 533 for this reason, not to mention the wider FoV and deeper full well.



#5 CCD-Freak

CCD-Freak

    Vendor - Portable Observatories

  • *****
  • Vendors
  • Posts: 1,863
  • Joined: 17 Jan 2008
  • Loc: Whitesboro,Texas

Posted 31 March 2020 - 10:00 AM

I have a 127 Mak-Cass on a Sirius EQ mount. I prefer OSC cameras and live with Bortle 6 skies.

I started with the original Orion Starshoot DSC Cooled camera with a SAC F3/F5 reducer screwed into the nose piece of the camera.

I was pleased with what I could get from it, with my 60-90 second frames. (I never Bin)

When Windows XP retired, so did this camera (which still works nicely, with Windows XP)

Original Starshoot DSC CCD Specs:
  Effective pixels: 752H x 582V (440k pixels)
  Total pixels: 795H x 596V (470k pixels)
  Chip size: 6.00mmH x 4.96mmV
  Pixel size: 6.5umH x 6.25umV

 

I then switched to using my Canon T5i attached to a Celestron F/6.3 Reducer

Effective pixels: 5184H x 3456V )(18M pixels)
Total pixels:
Chip size: 22.3mm x 14.9mm (APS-C)
Pixel size: 4.30umH x 4.30umV

 

I prefer keeping the F6.3 Reducer in place and I believe a cooled OSC astro camera may be more sensitive than my T5i and allow me to capture more data in less time.

I was thinking that either one of these cameras would be a better fit for my imaging train, sky conditions,etc. I do prefer the ASI line since I'm now using the 290mm-mini for my guide camera.

 

ASI294MC-PRO  11.7mp  4.63 um pixels, 4144x2822, backlit, zero amp glow, 4/3" sensor 23.2mm diagonal, readnoise 1.2e, qe 75%, full well 63.7ke, exp 32us-2000s, usb3/usb2

ASI533MC-PRO  9.07mp  3.76 um pixels, 3008x3008, backlit, zero amp glow, 11.31mmx11.31mm sensor, readnoise 1.0e-3.8e, qe >80%, full well 50ke, exp 32us-2000s, usb3

 

Was it the original pixel size (6.25um) that gave me the images I liked? or the fact that it was cooled?

 

I'm not certain which camera would be a better fit for my setup...

 

Thoughts?

The ASI294MC-Pro does have amp glow but that can normally be calibrated out but some have reported difficulty doing it.

 

I chose the ASI533MC-Pro myself after having an ASI1600MC-Cool which was a very nice camera but it had it's own quirks. I am currently suffering through the cloudy sky curse waiting for a chance to use my ASI533MC-pro.

 

My $.02

 

John

CCD-Freak

WD5IKX


  • jdupton likes this

#6 mtc

mtc

    Ranger 4

  • -----
  • topic starter
  • Posts: 383
  • Joined: 04 Apr 2005
  • Loc: Chelmsford, MA

Posted 31 March 2020 - 10:47 AM

Amp glow on a cooled camera?

Does one expect amp glow on all cooled cameras?



#7 CCD-Freak

CCD-Freak

    Vendor - Portable Observatories

  • *****
  • Vendors
  • Posts: 1,863
  • Joined: 17 Jan 2008
  • Loc: Whitesboro,Texas

Posted 31 March 2020 - 11:00 AM

Amp glow on a cooled camera?

Does one expect amp glow on all cooled cameras?

Yes....Most CMOS cameras have some amp glow which often looks like a starburst or a diffuse glow at the edge of an image.  Normally it is calibrated out with the use of Dark frames.  Some of the latest crop of cameras from ZWO have "No amp glow". The ASI533MC-P, ASI2600MC-P, ASI6200MC-P and the ASI6200MM-P are the ones that have this technology.  Over time I expect more cameras will have this improvement.

 

Another $.02

 

John

CCD-Freak

WD5IKX


Edited by CCD-Freak, 31 March 2020 - 11:04 AM.


#8 dghent

dghent

    Messenger

  • *****
  • Vendors
  • Posts: 445
  • Joined: 10 Jun 2007

Posted 31 March 2020 - 11:04 AM

Amp glow on a cooled camera?

Does one expect amp glow on all cooled cameras?

A cooled sensor addresses dark current (electrons generated from latent heat tumbling into pixel wells), not amp glow.

 

Amplifier glow and how prevalent it may be is a function of sensor design (front-side vs. back-side) and how the camera firmware drives the sensor in between and during exposures (often referred to as amp noise reduction.)


  • mtc, CCD-Freak and bobzeq25 like this

#9 bobzeq25

bobzeq25

    Hubble

  • *****
  • Posts: 19,672
  • Joined: 27 Oct 2014

Posted 31 March 2020 - 11:35 AM

A bit more clarity.  CMOS cameras are characterized by on active chip circuitry.  When they're used for terrestrial photography, the shot exposures and large signal to noise ratio makes the heat from these completely negligible.

 

In long exposure astrophotography, with very low signal to noise ratio, the heat from the circuitry sometimes shows up as amp glow.  It increases with increasing subexposure time, and increased gain.  That means its more of an issue with narrowband.

 

It can be compensated for by properly calibrating the lights with flats, darks, and either bias or flat darks.  The choice of the last is camera specific.  People have been turning out superb images with cameras with amp glow for quite some time.

 

Some new astro cameras are designed to compensate for amp glow internally.  It's another valid way to deal with the issue, not a game changer.


Edited by bobzeq25, 31 March 2020 - 11:36 AM.

  • dghent and PartlyCloudy like this

#10 mtc

mtc

    Ranger 4

  • -----
  • topic starter
  • Posts: 383
  • Joined: 04 Apr 2005
  • Loc: Chelmsford, MA

Posted 31 March 2020 - 01:21 PM

This is helpful!

So, if I'm not interested in Narrowband, is the concern about amp glow greatly reduced or minimized such that it can be addressed with Darks?

I think I like the FOV provided with the 294 and the image scale is a little better (closer to 1) than the 533


Edited by mtc, 31 March 2020 - 01:30 PM.


#11 SilverLitz

SilverLitz

    Viking 1

  • -----
  • Posts: 647
  • Joined: 17 Feb 2018
  • Loc: Louisville, KY

Posted 31 March 2020 - 01:48 PM

Amp glow is an issue for LRGB and NB, but in all cases it calibrates out easily.  Your dark frames have to exactly match the sensor's temp (no problem with cooled cam), gain, and exposure time.  You can develop a master dark library by stacking 30-50 individual dark frames for the camera's specific temp, gain, and exposure time.   

 

I simplify this by always using the same temp (-10C) and gain (unity), but I have to have multiple sets for the differing exposures (standardizing to 30s, 60s, 120s, 240s; depending on your specific scope f/, sky conditions, camera).  Advanced imagers sometimes use a couple different gains, such as unity for NB and 50% unity for LRGB.  Lower gain has the advantage of increasing dynamic range, but disadvantage of increased read-noise and requiring longer exposures.


  • CCD-Freak likes this

#12 bobzeq25

bobzeq25

    Hubble

  • *****
  • Posts: 19,672
  • Joined: 27 Oct 2014

Posted 31 March 2020 - 03:59 PM

This is helpful!

So, if I'm not interested in Narrowband, is the concern about amp glow greatly reduced or minimized such that it can be addressed with Darks?

I think I like the FOV provided with the 294 and the image scale is a little better (closer to 1) than the 533

As I said.  Flats, darks, either bias or flat darks.  All 3.

 

My 183 has significant amp glow.  Properly calibrate the lights, it's gone.


Edited by bobzeq25, 31 March 2020 - 04:01 PM.

  • CCD-Freak likes this

#13 mtc

mtc

    Ranger 4

  • -----
  • topic starter
  • Posts: 383
  • Joined: 04 Apr 2005
  • Loc: Chelmsford, MA

Posted 31 March 2020 - 06:57 PM

Got it. I read that amp glow is more noticable with a 'higher gain' and 'longer exposures'.. so what is 'longer exposures'? 2min? 3 or 4 minutes? I don't plan on pushing the gain, so I'm wondering if amp glow will be negligible/minimal.
Thoughts?

#14 dghent

dghent

    Messenger

  • *****
  • Vendors
  • Posts: 445
  • Joined: 10 Jun 2007

Posted 31 March 2020 - 07:29 PM

Got it. I read that amp glow is more noticable with a 'higher gain' and 'longer exposures'.. so what is 'longer exposures'? 2min? 3 or 4 minutes? I don't plan on pushing the gain, so I'm wondering if amp glow will be negligible/minimal.
Thoughts?

That should be the longer the exposure, the more visually-apparent the amp glow will be.

 

But amp glow is calibrated out quite handily with dark frames. In fact, one of the nice things about moving to a cooled camera is that you'll be able to build a master dark library and not have to worry about collecting dark frames with each session.


Edited by dghent, 31 March 2020 - 07:30 PM.

  • mtc likes this


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