44 replies to this topic

[Gatoberto]

Hello all,

 

I am thinking of upgrading from my DSLR to a dedicated cooled color camera. I need advice deciding which would be a better fit for my current optics and targets:

 

Astro-Tech 72EDII focal length: 430mm, f/6 and with 0.8x reducer: focal length: 344mm, f/4.8.

 

My targets will mostly be deep sky objects: nebulae and bright galaxies. Depending on object size, I'd shoot with or without the FF/FR. I sometimes shoot from my city and from dark rural areas. 

 

I am considering these models:

ASI183MC-pro 

ASI294MC-pro

ASI533MC-pro

ASI585MC-pro

 

Budget is under $999. I played around with the CCD Suitability Calculator from astronomy.tools and I've read quite a few posts and guides and learned a few things, like it's important to have good pixel size to fit the particular telescope but I don't know how critical or important this is or if other factors are more important like bit depth, well size, larger pixels for S/N ratio, etc. This will be my first astrocamera so all these variables can be a bit overwhelming. I believe newer cameras should have better technology. I also have seen many images on Astrobin with the 72EDII with different cameras and to my beginner eye, they look pretty amazing. 

 

Any advice or recommendation would be very appreciated. Thank you!

 

[Tapio]

Of those it's either 533 or 585 (and there are other brands than ZWO...).

533 has square sensor and overal is better in some ways (14bit vs 12bit, slightly bigger sensor).

585 has slightle smaller pixels which fit better in short fl scopes.

Of those I would choose 533 (which I have done, just PO version), and I have uncooled version of 585 for planets.

[Gatoberto]

Thank you.

The 533 has 3.76um pixel size and if used with the FF/FR (fl: 344mm) the suitability calculator says it's slightly under sampled.  Does this have a significant impact on image quality or ability to capture fine detail or is not really a big issue?   

[unimatrix0]

Thank you.

The 533 has 3.76um pixel size and if used with the FF/FR (fl: 344mm) the suitability calculator says it's slightly under sampled.  Does this have a significant impact on image quality or ability to capture fine detail or is not really a big issue?   

No. Don't get caught up with the sampling. the 533 works just fine from 300mm to 4000mm focal length. 

 

The 2600 camera is the same, just in aps-c. 

 

If the issue would be as serious as the suitability calculator suggests, then 100s of thousands of people would be throwing away their cameras and ZWO and QHY and Touptek would be filing for bankruptcy and shutting down business. 

[Tkall]

533 MC Pro was my choice and I think it was the right choice for my level of expertise at the time, zero.

[Tapio]

No it's not a big issue. And at some point you can drizzle your images.

[pedxing]

Thank you.

The 533 has 3.76um pixel size and if used with the FF/FR (fl: 344mm) the suitability calculator says it's slightly under sampled.  Does this have a significant impact on image quality or ability to capture fine detail or is not really a big issue?   

Slightly undersampled is fine.

 

The secret with short focal length scopes is to dither aggressively during acquisition and then drizzle in post-processing.

[rgsalinger]

First of all, at 348mm and with 3.76 pixels you are not "slightly" undersampled, you are way undesampled (unless your seeing is awful) at 2.25"/pixel. The rule of thumb (Nyquist) is for the the image scale to be around 1/3 of the seeing. So, with that setup I'd be looking for small pixels and accepting that the FWD won't be that great. 

 

For example, if you have 2 arc second seeing, you won't be fully sampled with that camera until you get to around 900mm. People like to use calculators that are fiddled with by vendors to sell you stuff. I prefer to use this calculator and the rule of thumb which is derived from the Nyquist theorem. 

 

So, I think that my recommendation would be to go with the largest available chip and to reinforce Dave's point, dither and then drizzle to get nice round stars. That would mean buying the 294 (IIRC) and putting up with it's amp glow. That means, in turn, using longish (3 second or more) for your flat frames and never scaling your dark frames. I have the 294 on my Edge 11HD and it's a terrific camera. I'm sure that the 294MC will work just as well for you. 

[idclimber]

The 533mc is the best choice of all the cameras you listed. This is not even close, as pixel size is arguably the least important metric in comparing these cameras. Sensor size, dynamic range and ease of calibration are far more important. 

[rgsalinger]

I must be confused. I read that the 533 @ 11x11mm sensor is way smaller than the 294 sensor @ 19x13???? Did I get that backwards?

 

I don't really see why adhering to some simple calibration rules would play into the decision. Just dither, match the darks and take 3 second flats and you're good to go. It would seem a shame to get such a small chip when going from a DSLR to a cooled camera. 

[idclimber]

I must be confused. I read that the 533 @ 11x11mm sensor is way smaller than the 294 sensor @ 19x13???? Did I get that backwards?

 

I don't really see why adhering to some simple calibration rules would play into the decision. Just dither, match the darks and take 3 second flats and you're good to go. It would seem a shame to get such a small chip when going from a DSLR to a cooled camera. 

The 294mc is definitely larger. It's issue is it's unreliability and difficulty in calibration, otherwise it is a great camera. There are simply too many that struggle with this without a positive outcome. 

 

If I was the OP, I would seriously consider stretching the budget and consider a used ASI2600mc. They typically go for about $1,300 US. Alternatively one of the IMX571 clones. That however is not one of the choices and over the stated budget. 

[Gatoberto]

Thanks again for all the comments.

 

Apart from sensor size, are there any other advantages of the ASI294 over the ASI533?

 

So far I have just considered the ZWO cameras since I use the Asiair plus. But does anyone have another camera from another brand to recommend?

[unimatrix0]

Thanks again for all the comments.

 

Apart from sensor size, are there any other advantages of the ASI294 over the ASI533?

 

So far I have just considered the ZWO cameras since I use the Asiair plus. But does anyone have another camera from another brand to recommend?

Not really. It's really the sensor size that gets the 294 an advantage. 

 

On the other hand the 533 is very easy to use. No amp glow, no need for dark flats, but biases.  I haven't used a dark over one year with my 533mm pro. Before that I had the 533mc pro, again I didn't use darks. 

 

If you would have some extra money though, the 2600 sensor with the aps-c size  and 16bit dynamic range and similarly no amp glow is pretty much the "maxed out" camera you can have in 2024. 

Anyone that started out not long ago, and wanted a dependable camera that does very good, he/she is probably rocking a 2600mc pro, or some other camera with the same sensor, like QHY or Touptek. 

Edited by unimatrix0, 14 May 2024 - 04:45 PM.

[idclimber]

Thanks again for all the comments.

 

Apart from sensor size, are there any other advantages of the ASI294 over the ASI533?

 

So far I have just considered the ZWO cameras since I use the Asiair plus. But does anyone have another camera from another brand to recommend?

That is about it, it is larger. The 533 has nearly two stops more dynamic range (13.5 stops at gain of 100 vs 11.25 at gain 108.), smaller pixels and is easier to take flats and calibrate. 

 

The 294 typically needs flats as long as 1 or 2 seconds, sometimes a bit longer and matching dark-flats to properly calibrate. This is not hard to manage if you have an adjustable light source. The 533/2600 and other cameras that share the same Sony sensors can take flats from a few tenths of a second to several seconds and can be calibrated with a single Master Bias. 

 

The ASIAIR only supports DSLRs and ZWO cameras. Other brands of astro cameras are intentionally excluded. 

[archiebald]

Thanks again for all the comments.

 

Apart from sensor size, are there any other advantages of the ASI294 over the ASI533?

 

So far I have just considered the ZWO cameras since I use the Asiair plus. But does anyone have another camera from another brand to recommend?

Well, since you currently have the ASI Air, unfortunately you cannot consider any other maker's astro cameras.

 

I know that if it were me, I would choose a IMX533 sensor over the 294 simply because of the amp glow in the 294.

 

However, a much better (but much more expensive) camera would be one using the IMX571 sensor (as used in the ASI2600), since it has the same pixel size as the IMX533, but has the advantage of the much larger sensor for wider fields, while you can always crop back down for smaller objects.

 

This is exactly the process I went through when I bought my Poseidon-C (IMX571) last year.  Cry once, but now I have a camera that should serve me many years as I grow in the hobby.

 

However, assuming that you do decide to escape out of the ZWO prison to EKOS, NINA or some other acquisition system, then I'd recommend looking at Player One - excellent cameras, great service.

 

You don't mention your geographical location but if you are in the USA then you could look also into the OGMA brand, which is a US based company selling on re-branded and slightly tweaked QHY cameras.  QHY are already very well respected plus you'd have the added bonus of domestic sales / service.

 

According to numerous commenters on these forums, the after sales support of ZWO is patchy at best.  Their equipment is mostly reliable but if or when something does break, the reports on after sales service support ranged from okay to abysmal.

Edited by archiebald, 14 May 2024 - 05:29 PM.

[Gatoberto]

Seems like the 533 would be much easier to use for a beginner than the 294 though it has a smaller FOV.

 

Yes, after reading some posts, I am now starting to consider the 2600 as it would be nice to have the bigger FOV and also to crop images when imaging smaller objects. And like you say, perhaps this camera will still be great in a few years if I end up adding a longer focal length telescope.

 

I live in Portland, Oregon. I will take a look at Player One. However, being a beginner in AP, the Asiair is a game changer. 

[archiebald]

Seems like the 533 would be much easier to use for a beginner than the 294 though it has a smaller FOV.

 

Yes, after reading some posts, I am now starting to consider the 2600 as it would be nice to have the bigger FOV and also to crop images when imaging smaller objects. And like you say, perhaps this camera will still be great in a few years if I end up adding a longer focal length telescope.

 

I live in Portland, Oregon. I will take a look at Player One. However, being a beginner in AP, the Asiair is a game changer. 

Having never used an ASI Air, can't really say much, but NINA is easy. It, and all other necessary software is free.  As for hardware, you'd need a PC or mini-PC but even if you end up hating the software you could always repurpose the Mini-PC as a usable desktop or network server.  When you stop using an ASI Air, its only use is as a paper-weight.

Depending on your setup, you might need a powerbox or powered USB hub etc, but nothing that is difficult and it would give you a chance to spread your wings.

[rgsalinger]

It's important in this hobby to differentiate between things that you have to do once to get going - set up a correct flat workflow - from things that will always be an issue - like having a camera with too small a chip. It would be easy to step the OP through setting up a set of 294MC flats, if that really turns out to be challenging  With a 533MC there's nothing anyone can do to help make that small FOV bigger. 

 

I would never take long exposures with any astronomy camera and not use darks. I have 5 cameras (2 QHY and 3 ZWO on 5 OTAS) and they ALL produce the best results when using dark frames that are equal in duration the light frames. Yes you can fix somethings up with complex post processing but it's just too easy to build a dark library on a non imaging night every 6 months of so.

 

I do not find that I need dark flats with my 294. Even with 10 second exposuses (so far) I've not seen any advantage in the final stacked imaging from using them rather than bias frames. If you take very long duration flats (which won't happen with a color camera) then it becomes a problem. 

 

The choice of imaging software has nothing to do with whether or not one would use a 294 versus a 533. 

 

I don't think that the OTA's owned by the OP will support the use of a 2600. Of course that depends on what is acceptable in terms of star shapes, particularly in the corners. So, while I think that the 2600's are generally wonderful choices, there's no point in owning one if you are just going to have to crop. See if you can find some full resolution 2600MC  images on astrobin taken with that scope (particularly with the reducer) before spending money. 

[archiebald]

It's important in this hobby to differentiate between things that you have to do once to get going - set up a correct flat workflow - from things that will always be an issue - like having a camera with too small a chip. It would be easy to step the OP through setting up a set of 294MC flats, if that really turns out to be challenging  With a 533MC there's nothing anyone can do to help make that small FOV bigger. 

 

I would never take long exposures with any astronomy camera and not use darks. I have 5 cameras (2 QHY and 3 ZWO on 5 OTAS) and they ALL produce the best results when using dark frames that are equal in duration the light frames. Yes you can fix somethings up with complex post processing but it's just too easy to build a dark library on a non imaging night every 6 months of so.

 

I do not find that I need dark flats with my 294. Even with 10 second exposuses (so far) I've not seen any advantage in the final stacked imaging from using them rather than bias frames. If you take very long duration flats (which won't happen with a color camera) then it becomes a problem. 

 

The choice of imaging software has nothing to do with whether or not one would use a 294 versus a 533. 

 

I don't think that the OTA's owned by the OP will support the use of a 2600. Of course that depends on what is acceptable in terms of star shapes, particularly in the corners. So, while I think that the 2600's are generally wonderful choices, there's no point in owning one if you are just going to have to crop. See if you can find some full resolution 2600MC  images on astrobin taken with that scope (particularly with the reducer) before spending money. 

Regarding the point I have bolded, I have a William Optics Z73 that has the same FL specs with and without the reducer.  I know it is not the same optics, but I can vouch for the fact that the IMX571 sensor works perfectly across the entire sensor at 430mm and I only see just the tiniest amount of minor vignetting at 344mm when using the 0.8 reducer, and that is eliminated completely with flats.

 

I won't comment on star quality in the corners (mine are excellent) because that might vary with the optical quality of his scope.

 

EDIT - Also, as he mentioned, he has been shooting with a DSLR already, I'd assume he already has experience with an APS-C sized sensor.

Edited by archiebald, 15 May 2024 - 02:08 AM.

[vidrazor]

I live in Portland, Oregon. I will take a look at Player One. However, being a beginner in AP, the Asiair is a game changer. 

Yes, the bane of the ASIAIR prison. ZWO always suckers newbies in with it. "It's so easy!!!". They're like heroin dealers.

You could look into a Stellarmate setup, which also comes with a cellphone/tablet app to let you control the system, or you can control it from a laptop or desktop. You can load Stellarmate compiled for Intel on a MiniPC and replace the Windows operating system.

There is one other system that runs on Windows that also has a phone/tablet app to control your system, and give you the luxury of running NINA or Astro Photography Tool on a MiniPC.

 

Either one of these two options will give you a similar experience to what you're doing now while not restricting you from using whatever hardware that you would like to use.
 

Edited by vidrazor, 15 May 2024 - 02:59 AM.

[Gatoberto]

I've mostly used a Canon 600D (T3i) which is an APS-C with the AT72EDII. I also have a full frame 5DIV which I've used on a few occasions and a Fuji XT-2. I pretty much only use the T3i because of the flip screen and I use a clip in light pollution filter. So far I haven't had any issues using an APS-C sensor (but again, I'm just a beginner). The main reason to get a dedicated astro camera is the cooling, as I shoot mostly in the warm summer-early fall months (cloudy the rest of the year here in the NW). And of course looking for lower noise and better image quality.  

 

What I mentioned about cropping with a bigger sensor like the 2600, I was thinking only in situations when imaging a smaller object like a galaxy, which I do with the DSLR. In this case would higher resolution or smaller pixels be better?  

 

I got the Asiair because of a friend's recommendation, and I didn't really shop around to see if there were other similar alternatives. As someone who started dabbling in AP back in the 80's with a 8" Newtonian, when there was only film, your eye was the guidescope, and none of this cool gadgets, when I saw  the Asiair and it's capabilities, I was awe-struck as you can imagine

[72Nova]

With your budget I’d recommend the 533mc. It was my first Astro camera purchase and I also have a 294mm (mono). I prefer the larger chip of the 294mm, but calibration frames are tricky, not beginner friendly.

If you can stretch your budget a bit, the 2600mc price has been reduced to $1400. I’m planning to purchase the 2600mc for my 90mm triplet for use at a dark site.

[Oort Cloud]

Of those it's either 533 or 585 (and there are other brands than ZWO...).
533 has square sensor and overal is better in some ways (14bit vs 12bit, slightly bigger sensor).
585 has slightle smaller pixels which fit better in short fl scopes.
Of those I would choose 533 (which I have done, just PO version), and I have uncooled version of 585 for planets.

533 has double the sensor size for less than double the price. It's a no brainer.

[Oort Cloud]

Regarding the point I have bolded, I have a William Optics Z73 that has the same FL specs with and without the reducer. I know it is not the same optics, but I can vouch for the fact that the IMX571 sensor works perfectly across the entire sensor at 430mm and I only see just the tiniest amount of minor vignetting at 344mm when using the 0.8 reducer, and that is eliminated completely with flats.

I won't comment on star quality in the corners (mine are excellent) because that might vary with the optical quality of his scope.

EDIT - Also, as he mentioned, he has been shooting with a DSLR already, I'd assume he already has experience with an APS-C sized sensor.

Focal length has nothing to do with whether it will vignette.

The only way to assess this is to go by what the mfg says is compatible, or based on reports from users with the same optics (including any reducers, flatteners, etc.) and an APS-C sensor.

[Oort Cloud]

Yes, the bane of the ASIAIR prison. ZWO always suckers newbies in with it. "It's so easy!!!". They're like heroin dealers.

You could look into a Stellarmate setup, which also comes with a cellphone/tablet app to let you control the system, or you can control it from a laptop or desktop. You can load Stellarmate compiled for Intel on a MiniPC and replace the Windows operating system.

There is one other system that runs on Windows that also has a phone/tablet app to control your system, and give you the luxury of running NINA or Astro Photography Tool on a MiniPC.

Either one of these two options will give you a similar experience to what you're doing now while not restricting you from using whatever hardware that you would like to use.

The ASIair is easily the smartest move they've ever made as a company. I'd bet they've made enough profit by now on other items (cams, EFW, EAF) to cover the R&D that it took to create it. Especially since basically half of what runs on it is open source software.

Edited by Oort Cloud, 15 May 2024 - 11:34 AM.