Zwo 183 v 533

[jackp93]

Hi all

im looking at treating myself to a proper dedicated astro camera for my skywatcher evo star 72ed. As I’ve got an asiair pro it will need to be a zwo and I’ve narrowed it down to the 183 mc and 533 mc using the astronomy.tools calculator. What are peoples opinions on both is one any better than the other?

 

thanks

 

Jack

[Adam J]

18 minutes ago, jackp93 said:

Hi all

im looking at treating myself to a proper dedicated astro camera for my skywatcher evo star 72ed. As I’ve got an asiair pro it will need to be a zwo and I’ve narrowed it down to the 183 mc and 533 mc using the astronomy.tools calculator. What are peoples opinions on both is one any better than the other?

 

thanks

 

Jack

The 533 significantly more sensitive than the 183, also the thing that CCD calculator will not tell you is at a 72mm objective is not able to resolve detail to 1.18 arcseconds per pixel irrespective of the camera you use so you will gain no resolution by going for the smaller pixels of the 183 over the larger more sensitive ones of the 533 which will give you a very respectable 1.8 arcseconds per pixel. 

The 183 comes into its own in fast large aperture optical systems such as a hyperstar but even then you might still chose the 533. 

Adam  

 

 

[The Lazy Astronomer]

Out of those 2, my vote would be the 533 as well.

If you could stretch to it, the 2600 would be the best choice.

[rickwayne]

183 owner here -- I would go with the newer, more capable camera.  I love the 183, but it has hella amp glow (calibrates out perfectly, true), and a pretty small dynamic range. The 533 has  much greater full-well capacity and I believe a 14-bit  ADC as well.

[jackp93]

Thanks everyone for all the comments, I’m definitely going to get the 533, I’ll now just have to wait to for first light to have it in stock.

all the best

Jack

[daz]

I have that combo! 

Be aware the the chip cover is not UV/IR blocking so you'll want a UV/IR filter - and I find with my 72 that the blue light on stars is slightly bloated. I'm waiting on a Baader Fringe killer to test against.

As with all ZWO cameras you get all the adapters, spacers and cables you need! It's a great package!

I also have the ZWO OAG, and it all just fits together perfectly!

M31 taken with the 533 and ED72....

[vlaiv]

18 hours ago, Adam J said:

The 533 significantly more sensitive than the 183

How come?

ASI533 has 80% QE while ASI183 has 84% peak QE

[Adam J]

3 hours ago, vlaiv said:

How come?

ASI533 has 80% QE while ASI183 has 84% peak QE

Read noise per unit area is much higher in the 183. 

Looking at unity gain for both to make my life easier, 2.4um pixels with a 2.2e read noise vs 3.75um pixels with a 1.5e read `noise. If you are doing duel narrow band read noise should be dominant unless you do very long exposures and the 183 does not like that from what i have heard.  

Pixel area of 533 =  3.75^2 = 14.06um^2 

Pixel area of 183 = 2.4^2 = 5.76um^2

Read noise per unit area 533 = 1.5/14.06 = 0.106e/um^2

Read noise per unit area 183 = 2.2/5.76 = 0.382e/um^2

You could go with 2x2 on the 183 = 2.97 / 23.04 = 0.129/um^2 

But that's still worse than the 533 even if you further take into account the QE difference. 

The performance difference will be less significant for RGB imaging of course under less than dark sky as other noise sources will start to dominate and the read noise will be burried. 

But then you have the 183 AMP glow which to my mind must add noise under that area of the chip and you have the the fact that even if you did go 2x2 in processing you would have worse sampling for no gain and so overall the 533 is just plain better. 

 

But the real  killer for me is that if you scroll through astrobin the 533 is on average just producing better images. 

 

Do you have a different view?

 

Adam

 

 

 

 

 

 

Edited November 26, 2021 by Adam J

[vlaiv]

3 minutes ago, Adam J said:

Do you have a different view?

Somewhat.

3 minutes ago, Adam J said:

Read noise per unit area is much higher in the 183. 

Not sure if this is relevant metric. Impact of read noise depends on other noise sources and one can control it with single exposure length (as it is per exposure). That way you can get same total read noise per session between cameras (adjusted for pixel size or not - either way it is controllable quantity). This for example should be taken into account when planning on binning the data as software binning increases read noise.

14 minutes ago, Adam J said:

But then you have the 183 AMP glow which to my mind must add noise under that area of the chip and you have the the fact that even if you did go 2x2 in processing you would have worse sampling for no gain and so overall the 533 is just plain better. 

Amp glow just looks ugly - but it really does not add much dark current and hence noise. I've measured amp glow in several cameras and amp glow tends to be 1-2e higher than surrounding dark signal - so noise impact is negligible.

Granted, dark current is stronger in ASI183, and quite so compared to ASI553, but both cameras have very low dark current to begin with. ASI183 has ~0.003e/s/px at -20C. In 10 minute exposure - dark current will be 1.8e and corresponding noise will be 1.34e - less than read noise.

Overall, I'd say that these two cameras are very similar in performance if we take peculiarities into account. Some might prefer not to have to think about amp glow and binning, while others will appreciate flexibility of small pixels and possible different binning factors depending on their setup.

I would not declare "clear winner" either of them.

[vlaiv]

13 hours ago, rickwayne said:

183 owner here -- I would go with the newer, more capable camera.  I love the 183, but it has hella amp glow (calibrates out perfectly, true), and a pretty small dynamic range. The 533 has  much greater full-well capacity and I believe a 14-bit  ADC as well.

Dynamic range is irrelevant when doing astrophotography. We increase dynamic range of the image many fold when doing stacking.

Saturation is not important either as no camera can capture true dynamic range in any target in single exposure. Just think about it - it can easily happen to have 15 mags of difference in stars in your image (you can have mag4 star next to mag19 star). That is one million times brightness difference.

Even 10 mags of difference will give x10000 in brightness - that is hard to record with even 16 bit camera if you want to have any sort of SNR on fainter star (say SNR of 5 - that would make signal at least 25 and 10000 stronger is 250000 which needs ~18bits to be recorded.

When we want to capture full dynamic of the image - we do "HDR composing" - using exposure time to capture both faint (long exposure) and bright detail (short exposure) and then combine the two.

[AstroNebulee]

Hi

@jackp93 there's a 533mc pro in flo atm on offer at £809.

[Adam J]

1 hour ago, vlaiv said:

Somewhat.

Not sure if this is relevant metric. Impact of read noise depends on other noise sources and one can control it with single exposure length (as it is per exposure). That way you can get same total read noise per session between cameras (adjusted for pixel size or not - either way it is controllable quantity). This for example should be taken into account when planning on binning the data as software binning increases read noise.

Amp glow just looks ugly - but it really does not add much dark current and hence noise. I've measured amp glow in several cameras and amp glow tends to be 1-2e higher than surrounding dark signal - so noise impact is negligible.

Granted, dark current is stronger in ASI183, and quite so compared to ASI553, but both cameras have very low dark current to begin with. ASI183 has ~0.003e/s/px at -20C. In 10 minute exposure - dark current will be 1.8e and corresponding noise will be 1.34e - less than read noise.

Overall, I'd say that these two cameras are very similar in performance if we take peculiarities into account. Some might prefer not to have to think about amp glow and binning, while others will appreciate flexibility of small pixels and possible different binning factors depending on their setup.

I would not declare "clear winner" either of them.

and yet i just dont see the same quality of images coming out of the 183 as i do the 533. That may be to taist / subjective but I see it as a significant gap not just a small one. What you say is true about exposure length but it would be a significantly longer exposure and for me one of the advantages of CMOS is shorter exposures. I often do 30s exposures with my ASI1600mm pro.

I would find the image ideal for the OPs scope with the 533 and a binned 183 to be a little short on pixels for my taist (I like to print my images).

Adam

 

 

[jackp93]

1 hour ago, AstroNebulee said:

Hi

@jackp93 there's a 533mc pro in flo atm on offer at £809.

Thanks @AstroNebulee for the heads up it’s all paid for and it should arrive tomorrow.  I even accidentally bought a auto focuser to go on the sw72 so I think I now have a almost fully automated system. 

[Clarkey]

1 hour ago, jackp93 said:

I even accidentally bought a auto focuser

I'm always accidentally buying things too.🤣

[AstroNebulee]

1 hour ago, jackp93 said:

Thanks @AstroNebulee for the heads up it’s all paid for and it should arrive tomorrow.  I even accidentally bought a auto focuser to go on the sw72 so I think I now have a almost fully automated system. 

No problems, glad you got it now and cheaper too, enjoy it and the auto focuser. I'm just saving up for the zwo asi 294mc pro,probably in 2 years time I'll afford it haha. Clear skies 

Edited November 26, 2021 by AstroNebulee