ZWO ASI1600MM-C vs ASI183MM-C

[MarsG76]

Hi All,

I'm looking at going the CCDs direction... one these two cameras are the ones's that I'm thinking of getting...

Does any one have any experience with the 183?, it's quite new but perhaps someone has experience with one...

 

 

[Ant]

I have a ASI183mm pro coming tomorrow. But it'll be a little while before i use in anger as I'm building my setup from the start.

Ant

[MarsG76]

1 hour ago, Ant said:

I have a ASI183mm pro coming tomorrow. But it'll be a little while before i use in anger as I'm building my setup from the start.

Ant

Excellent, hope you write a review....

[Gina]

I haven't come across the ASI183MM-C yet - who sells it?  Please.

[Thalestris24]

12 minutes ago, Gina said:

I haven't come across the ASI183MM-C yet - who sells it?  Please.

It's a new zwo cam, Gina. It has a 1" sensor, high QE and 20MP. But it only has 2.4um pixels... I expect FLO will be stocking it. It should be cheaper than the 1600mm-pro.

Louise

[alexbb]

3 hours ago, Gina said:

I haven't come across the ASI183MM-C yet - who sells it?  Please.

TS already list it

[vlaiv]

Not really something comparable.

What I don't like with 183mmc compared to 1600mmc is:

- smaller pixel size

- smaller chip size

- more read noise

- lesser QE at Ha (well, it is only if we observe relative graphs, in absolute terms 183 is quoted to have up to 84% peak QE, but then again, I'm a bit skeptical of "up to" claims). On the other hand 1600mmc is quoted to have "more than 60% peak QE". Don't you just love these precise specs?

What scope / scopes are you planing to pair it with?

[Adam J]

25 minutes ago, vlaiv said:

Not really something comparable.

What I don't like with 183mmc compared to 1600mmc is:

- smaller pixel size

- smaller chip size

- more read noise

- lesser QE at Ha (well, it is only if we observe relative graphs, in absolute terms 183 is quoted to have up to 84% peak QE, but then again, I'm a bit skeptical of "up to" claims). On the other hand 1600mmc is quoted to have "more than 60% peak QE". Don't you just love these precise specs?

What scope / scopes are you planing to pair it with?h

I would think it had a higher QE in ha being back side illuminated. Also it's actually got AR glass. You can bin the pixels and the higher noise is of a type that should calibrate out..in theory and is still well under 2e at any rate. So the main issue is the size of the sensor. 

[vlaiv]

5 minutes ago, Adam J said:

I would think it had a higher QE in ha being back side illuminated. Also it's actually got AR glass. You can bin the pixels and the higher noise is of a type that should calibrate out..in theory and is still well under 2e at any rate. So the main issue is the size of the sensor. 

Random noise is never calibrated out. Although technically noise (any unwanted signal can be considered noise), I don't consider either bias signal, nor dark current signal to be true type of noise - those calibrate out. What is left is true noise - random kind - that you cannot calibrate out (read noise and dark current noise - shot noise from dark current signal).

And for higher QE, well I do agree that on paper back side illuminated CMOS should have higher QE, I'm not convinced that it is high as quoted. I'm having trouble finding true QE curves for any Sony CMOS sensors. They always release relative QE curves, those while being helpful to judge response in different parts of spectrum don't paint full picture. On their website only information on sensitivity is given in rather strange units (something like millivolt level at 1/30s exposure with F/5.6 lens system???? - probably targeted at surveillance and industry applications) , and often in comparison to their previous Gen sensors of similar type.

I do have 178mcc camera, and I've taken some images with it. It is also back illuminated camera with 2.4um pixel size, although much smaller in size and it has lower read noise.

My 1600mmc just leaves it in dust on TS 80mm F/6 Apo (yes I know mono vs osc, but still quite a bit of difference), and I would not dream of using 178mcc with RC 8" for anything but planetary imaging, well with exception of maybe trying lucky imaging on planetary nebulae. For the time being I see that camera in either some future crazy experiments with EAA if I manage to stack reducers with success on RC 8" or as color grabber with Samyang 135mm for mono data from ASI1600 and TS80mm.

I'm not saying that 183 is bad camera, I'm just saying that I would personally consider it for very special application / setup. For example I think it would be killer combination with 6" F/2.8 crazy fast astrograph for EAA. It would give base resolution of ~1.2"/pixel and with such MP count ( 5496 x 3672 ) you can easily have up to 4 magnifications with decent image size: no bin - 1.2"/pixel, very large pan area at max zoom, then bin x2 would give you 2.4"/pixel and 2298x1863 pan area, bin x3 would give you 3.6"/pixel and if you are using some sort of projector for outreach (normally with resolution of 1024x768 or something like that) 1832x1224 still leaves a bit of room to pan around. Finally at bin x4 you would get 1374x918 - that is still decent number of pixels to go on display.

Ok, so you might say something like: you can bin it and it will give you decent resolution even on longer focal lengths. That equates to having a 4.8um pixel camera with read noise of 4e and 13bit A/D (if you look at the graph to reach 2e read noise you must go with ADU 0.5 or lower and Gain of 160 or higher, and that really leaves you with 11 usable bits out of 12bit ADC - when you bin x2 you add 2 bit of information so you end up with 13bit A/D).

Why not go for ASI294MC then? It is a bit more expensive, but for price difference you get 13bit ADC, pixel size of 4.63um and less than 2e noise, not to mention imaging size / fov size.

[MarsG76]

2 hours ago, vlaiv said:

What scope / scopes are you planing to pair it with?

I'm planning on imaging through the 8" SCT at 2032mm and 1280mm using the focal reducer, and also through the 80mm 500mm focal length refractor....

 

Initially I was looking at the QSI683, but when I saw the ASI1600, I was a lot cheaper ($1899 vs about $6000) and seems to not only be latest tech but comparable but on cloudy nights a test showed that it actually exceeds the quality/sensitivity and has lower noise level compared to the KAF8300.

I was siding on the ASI1600mm cool version but that found info on the ZWO site about the 183 that just came out.. very good descriptor, especially the high QE so I was wondering if anyone had any experience with it... I know that its fresh, and the small pixels are the only thing that is of a concern to me.

As far as the size of the sensor is concerned, both cameras are close to the APS-C size, just a bit narrower.... and the larger pixels of the ASI1600 would be beneficial... 16 Mega Pix is more than enough, I mean I'm imaging with a modded 40D and it 10Mega pixel... even than I have to scale down to 2592 x 1296 to bring in with the size of the green bayer limited resolution..

I know that either imager is a improvement.... but if I'm going to spend the money, I want to spend right since it will be with me probably for 10 years.

Thanks for the comment and advise every one.

 

 

[alexbb]

6 hours ago, MarsG76 said:

I'm planning on imaging through the 8" SCT at 2032mm and 1280mm using the focal reducer, and also through the 80mm 500mm focal length refractor....

6 hours ago, MarsG76 said:

and the small pixels are the only thing that is of a concern to me.

With the 8" SCT you would need a very good mount and exceptional seeing in order not to oversample too much. You aim for 0.39"/pixel reduced and 0.24"/pixel at native FL. The 1600 has rather small pixels too. 0.61"/pixel with the reducer.
Neither the 80/500 scope is fast for those tiny pixels.
To gather enough light to make a difference between the noise and the faint signal, you need a lot of exposure time. I usually aim for >6h at F/4-F/4.5 for each lum/narrowband channel with an ASI1600's pixel covering 2.5 times the area of an ASI183's pixel. You can get away with shorter exposure if you image bright targets or if you downscale the image, but then why so small pixels?

 

6 hours ago, MarsG76 said:

As far as the size of the sensor is concerned, both cameras are close to the APS-C size, just a bit narrower....

 

The 1" size sensor is quite small compared to the APS-C: http://astronomy.tools/calculators/field_of_view/?fov[]=69||1115||1|1|90&fov[]=69||272||1|1|90&fov[]=69||119||1|1|90&messier=42

I'm also interested in this camera, but only if it's significantly cheaper than the 1600. I plan to put it on a 300mm F4 lens to complement an 80/400 scope and the ASI1600. Their FOV is very close. Perhaps cheaper than another 80/400 scope and 1600 camera

[MarsG76]

1 hour ago, moise212 said:

With the 8" SCT you would need a very good mount and exceptional seeing in order not to oversample too much. You aim for 0.39"/pixel reduced and 0.24"/pixel at native FL. The 1600 has rather small pixels too. 0.61"/pixel with the reducer.
Neither the 80/500 scope is fast for those tiny pixels.
To gather enough light to make a difference between the noise and the faint signal, you need a lot of exposure time. I usually aim for >6h at F/4-F/4.5 for each lum/narrowband channel with an ASI1600's pixel covering 2.5 times the area of an ASI183's pixel. You can get away with shorter exposure if you image bright targets or if you downscale the image, but then why so small pixels?

 

The 1" size sensor is quite small compared to the APS-C: http://astronomy.tools/calculators/field_of_view/?fov[]=69||1115||1|1|90&fov[]=69||272||1|1|90&fov[]=69||119||1|1|90&messier=42

I'm also interested in this camera, but only if it's significantly cheaper than the 1600. I plan to put it on a 300mm F4 lens to complement an 80/400 scope and the ASI1600. Their FOV is very close. Perhaps cheaper than another 80/400 scope and 1600 camera

I noticed that the ASI1600 has a larger sensor, and pixels... this one with me is so far the winning camera.... I'm sure that it'll be OK with reference to oversampling... I'm generally able to get tracking 0.38-0.6ish so it'll be ok.... I can always bin the subs.... at 2000mm FL imaging I'd have to get a much more expensive camera than even teh QSI683 but surely the ASI1600 will be a major improvement over a modded uncooled DSLR.

 

[Adam J]

The 183m might be an interesting pairing with a short focal length scope / 200mm lense as part of a cheaper mobile setup.