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Walking on the Moon

ZWO Chips...( 178 or 183)... one size suits all....


Craney
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Evening everybody,

Apologies if I am making a huge error in logic and knowledge here, but... I was looking at the the ZWO range of CMOS cameras available and was wondering if there is any advantage in buying the 178 chip  over the 183 chip? 

Specifically....these cameras...

https://www.firstlightoptics.com/zwo-cameras/zwo-asi178mc-cool-usb-3-colour-camera.html

https://www.firstlightoptics.com/zwo-cameras/zwo-asi-183mc-pro-usb-3-cooled-colour-camera.html

 The 183 is  just a bigger chip, right ?? ( 20Mpx compared to the 178's  6Mpx), both have the same pixel size (2.4 microns).

 The 183 will have a wider FOV, but because it has a Region of Interest (ROI) capability, can you not just concentrate on a smaller region ?

 Looking at the 183 specification, it seems that you can zoom in on a 6Mpx portion of the chip  (3840×2160) , hence about the same equivalent FOV as the 178 camera..... so really the 183 offers two camera in one... and opens up the possibility of some planetary and Solar.

or am I completely wrong !!!   

Thanks for any help on this. 

 

Sean.

(ps.  I'll save the 183C vs 183M debate til later... ;) )

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Hi @Tim,    Is this because of the short exposure and many,many subs  rule for CMOS ??   (even if cooled ??)..... What is a typical file size of the 183 on full chip ??

 

Edited by Craney
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15 minutes ago, Craney said:

Hi @Tim,    Is this because of the short exposure and many,many subs  rule for CMOS ??   (even if cooled ??)..... What is a typical file size of the 183 on full chip ??

 

I find it best to capture to an external 1tb USB3 drive, this stops your HD getting clogged and also makes your files portable, they can be processed on the external drive then finished and saved on your HD.

Dave

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The way I understand it, the telescope produces an image that has nothing to do with the camera. You just put the camera in the way and it records what the telescope has produced. So, as you say, a bigger chip will simply record more of the image that the telescope has produced. If the pixels are the same size, the resolution of the image ("/px) will be the same, irrespective of the size of the chip - the same light will fall on the same number of pixels. So, to that extent, your analysis is right. Indeed, for planetary imaging, you would probably want to use the ROI feature even of the 178.

However, there are other things to consider. For example, the 183 is a 12-bit camera compared to the 14-bit 178. This means you have only 1/4 of the dynamic range (4096 cf 16384). It is, possibly, unfortunate that the "specificiations" do not allow a precise comparison on many of the criteria (eg the 183 has a peak QE of 84%, but I cannot see the peak QE figure on the 178 specs). And some of the terms may be comparable (in which case, why is different terminology used?) for example the 12.5mm "focus distance to sensor" of the 178 compared to the 6.5mm "back focus distance" of the 183.

Lots of things to consider, so not sure how much this has helped, except that (as far as your original post goes) you are right.

 

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My 2c

I went through this "discussion" looking for a camera for solar imaging at around 600mm focal length.

I ended up with the 183MM. I use Firecapture V2.6.

The SER files can be pretty big. A full frame SER of 26 sec (495 frames @ 19 fps) takes up 9.8Gb and takes AS! 826 sec (13.75 Min!) to process. The final image is a 38Mb TIFF.

The bit depth may be an issue but finding a program to process 12 or 14 bit video is an issue.

Running at an ROI similar to the ASI178 gives frame rates around 40 fps.

I works very well for me and compliments the larger pixel ASI 174 that I also use.

 

 

AS_stack_surface_cor_PSP_curves.jpg

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Thanks @Demonperformer   It is good to have a another viewpoint on the matter. Not being computer savvy I missed the  '12 bit' bit.

It is indeed a slightly murky field in terms of comparison.  It always amazes me that there are so many cameras available with so many specifications ( albeit, only slight differences).  Surely there must be one from an individual manufacturer that is universally accepted as being the 'best' for a particular imaging theme....  obviously not,  and cue many pages of forum debate.

With the price tag being considerable on these items, it is not a purchase that can be tried a few times until successful.  Oh bother.....

It might be best to wait until somebody comes along who has gone through the hard yards with various cams and declares the winner, or at least one that will deliver improved results across all fields of endeavour.

Thanks again.

Sean.

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Thanks @Merlin66

I am tending towards the 183 for Solar work, as I have an SW Equinox 80 (FL=625mm) for visible (Herschel Wedge)  and a PST (FL=400mm) for Ha.  

Blimey.....  9Gb files !!   ... It's looking like one purchase will begat another (1Tb disc) will begat another....(faster PC..).....   Oh Bother...

The 183 is also the equivalent upgrade ( if that makes sense!!)  to my modded 600D in terms of wide field DSO work as well.... so it is coming out on top.

Hmmmmm... plenty to mull over..... thank goodness for cloudy nights..... and days ;)

Cheers,

Sean.

 

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