Which CCD (or CMOS) Camera for Deep Sky Imaging

[Decimus (Richard)]

Hi Everyone,
I have a budget of between $4000 - $6000(max) with which I intend to purchase a deep sky imaging camera. I know this runs counter to what those who seek the sharpest images would say, but for me, a monochrome camera is not on my short-list, simply because, with clear skies being so rare nowadays, the time factor involved in imaging with various filters would only reduce imaging opportunities. I have a Nikon D850 which is a great camera, but not suited to the deep sky imaging I would like to do. I am not especially interested in planetary imaging, and as for the Moon, I think my DSLR (when attached to my WO refractor) can readily match images from other cameras, CCD or CMOS. I will be imaging with the WO GT102 (F6.9) and a WO reducer/flattener 8.

This limits my choices to colour CCD or CMOS cameras, though I prefer the former. Does anyone have any suggestions? Cameras from QSI, QHY and ATIK come to mind, as well as the Starlight Xpress Trius series (like the 26C). A broad selection, I know

FLI models seem to be very expensive.

Does anyone have any suggestions/recommendations? All comments and suggestions welcomed.

Cheers,
Richard

[Atmos (Colin)]

Do you have a flattener? Do you want a full frame or smaller sensor?

I can think of a few good colour CMOS sensors

[Decimus (Richard)]

Originally Posted by Atmos

Do you have a flattener? Do you want a full frame or smaller sensor?

I can think of a few good colour CMOS sensors

Hi Colin,
I have the WO reducer/flattener 8, still sitting there unused in its box since I bought it last year - it's BIG, too big, in my opinion for the WO GT102 (with which it is entirely compatible, according to WO), and IMHO, almost guaranteed to cause tube flexure in what is only a 4" telescope. I suspect I will sell it and buy something smaller.

As I have just discovered, sensor size is not everything, (pixel pitch, well depth, etc seem to be more important), but I guess a sensor of APSC or four-thirds size and up to full frame, would be great (and with a weight under 600g?) CMOS sensors are gaining ground (like the one in the ZWO ASI1600MM), but there are those that say CCDs still have the edge for overall image quality.

Would love to get some suggestions from you - and thanks for your reply!

Cheers,
Richard

[Atmos (Colin)]

It’s on the cheaper side but the ASI071 is good. APS-C, good dynamic range, 14-bit output. On the upper side is the QHY367 but that may be more than the $6,000 budget.

[traveller (Bo)]

Hi Richard,
Matching of optics to your camera is critical.
This is a good online tool for you to play with https://astronomy.tools/calculators/ccd_suitability
I have a ASI1600, which matched well with my FLT 110, and the ASI1600 (including the new pro OSC version) has a long list of happy owners!
Cheers
Bo

[Decimus (Richard)]

Originally Posted by Atmos

It’s on the cheaper side but the ASI071 is good. APS-C, good dynamic range, 14-bit output. On the upper side is the QHY367 but that may be more than the $6,000 budget.

Hi Colin,
Thanks for the advice. I certainly wouldn't mind the QHY367 which was near the top of a list of about 10 models. I was also thinking (dreaming) about the very pricey Atik 11 000 (9 micron pixels and full frame, their flagship)....if I keep saving....and then there's the Atik 490EX (within budget) and the Trius SX 26C (as mentioned earlier) which appears to be roughly APSC -sized CCD....

I guess I'll just keep looking until I am ready to buy, which hopefully, won't be too far away. Thanks again.

Cheers,
Richard

[gregbradley]

The idea that colour sensors reduce imaging time is not correct. They generally speaking have lower QE so they take total exposure time to get to the same level as filtered imaging with mono sensors. CCD cameras are typically around 60% QE for mono and about 28% or less for one shot colour (at least half as sensitive). I think the reality is more like 1/3rd as sensitive when all factors are considered.

But you can get caught out with an incomplete set of filtered data when using a mono sensor, so that is true. But then the colour data from the same time period from a colour sensor will be noisy so whilst you may get an image it may not be that pretty either.

I have used both and colour has its advantages but where you see its weaknesses most are in dust areas, dim areas of deep sky objects. Those will be noisy and are hard to get clean compared to filtered mono imaging.

So a 2nd hand QSI 683 WSG8 with filters is about the best setup I have seen in recent years. Many award winning images, the autoguiding function seems to work well and the smaller filters it takes allows using the better narrowband filters as the cost is kept done.

You would easily get one in your budget range. I see them on Astromart or CNN for about US$3000 - $3500 with filters.

Are these ASI type colour cameras much better than a modded DSLR? Especially say a full frame modded 6D (US$1000 or less 2nd hand)?

Full frame trumps these little ASI sensors. They are tiny.

Greg.

[Decimus (Richard)]

Originally Posted by traveller

Hi Richard,
Matching of optics to your camera is critical.
This is a good online tool for you to play with https://astronomy.tools/calculators/ccd_suitability
I have a ASI1600, which matched well with my FLT 110, and the ASI1600 (including the new pro OSC version) has a long list of happy owners!
Cheers
Bo

Thanks, Bo. The Astronomy Tools Calculator site is always on my list of favourites, but I usually use the other tools (like FOV calculator); so I'm glad you mentioned the CCD suitability tool which I had completely forgotten - it's very handy.

Re the ZWO ASI1600MM (monochrome), one of my friends down here in Tassie has one and the images he has produced with it are excellent. I don't know what the colour version would be like, but I have put that on the list too.

Thanks for the helpful advice.

Cheers,
Richard

[Decimus (Richard)]

Originally Posted by gregbradley

The idea that colour sensors reduce imaging time is not correct. They generally speaking have lower QE so they take total exposure time to get to the same level as filtered imaging with mono sensors. CCD cameras are typically around 60% QE for mono and about 28% or less for one shot colour (at least half as sensitive). I think the reality is more like 1/3rd as sensitive when all factors are considered.

But you can get caught out with an incomplete set of filtered data when using a mono sensor, so that is true. But then the colour data from the same time period from a colour sensor will be noisy so whilst you may get an image it may not be that pretty either.

I have used both and colour has its advantages but where you see its weaknesses most are in dust areas, dim areas of deep sky objects. Those will be noisy and are hard to get clean compared to filtered mono imaging.

So a 2nd hand QSI 683 WSG8 with filters is about the best setup I have seen in recent years. Many award winning images, the autoguiding function seems to work well and the smaller filters it takes allows using the better narrowband filters as the cost is kept done.

You would easily get one in your budget range. I see them on Astromart or CNN for about US$3000 - $3500 with filters.

Are these ASI type colour cameras much better than a modded DSLR? Especially say a full frame modded 6D (US$1000 or less 2nd hand)?

Full frame trumps these little ASI sensors. They are tiny.

Greg.

Thanks for your input and advice, Greg. I take your point about losing fine detail in nebulae with a colour CCD camera, but I suspect the QSI 683, magnificent as it is, will be a weighty set-up when laden with filters and could produce some tube flexure on my WO GT102? Hmm....Our weather down here is appalling and clear skies increasingly rare; hence my thinking about taking images quickly!

Have you any experience with Atik CCD cameras? Or Starlight Xpress Trius models? No one seems to talk about them and I am wondering how good they are.

Thanks again.
Cheers,
Richard

[Atmos (Colin)]

I personally wouldn’t bother with the Atik11000. Compared to the newer CMOS sensors it an ancient piece of antiquated hardware. That’s not to say you couldn’t get great images with it but for the cost buying new these days it’s just not worth it.

I have an ASI094 which is the ASI version of the QHY367 and is the same sensor as a Nikon D810A.
If you’re not wanting to get too serious and not wanting to do narrowband at the moment I’d stick with a OSC. More than anything, they’re less fuss. Once you get everything even semi automated it makes little difference but if you want to go and shoot for a couple of hours periodically, OSC is the way to go.

The ASI1600MC is good but the ASI071 is better in virtually every way. ASI might have a 24 MP full frame, can’t remember. The QHY367 is probably the best astro FF OSC on the market at the moment.

[Decimus (Richard)]

Originally Posted by Atmos

I personally wouldn’t bother with the Atik11000. Compared to the newer CMOS sensors it an ancient piece of antiquated hardware. That’s not to say you couldn’t get great images with it but for the cost buying new these days it’s just not worth it.

I have an ASI094 which is the ASI version of the QHY367 and is the same sensor as a Nikon D810A.
If you’re not wanting to get too serious and not wanting to do narrowband at the moment I’d stick with a OSC. More than anything, they’re less fuss. Once you get everything even semi automated it makes little difference but if you want to go and shoot for a couple of hours periodically, OSC is the way to go.

The ASI1600MC is good but the ASI071 is better in virtually every way. ASI might have a 24 MP full frame, can’t remember. The QHY367 is probably the best astro FF OSC on the market at the moment.

Thanks, Colin. You have persuaded me to maybe save up for the QHY367. ( believe the QHY12 is also very good?) Failing that, the ASI071 may be a cheaper alternative.

Meanwhile, back to some imaging with the D850.

Cheers,
Richard

[Camelopardalis (Dunk)]

And getting caught short with a mono sensor is easily avoidable...in SGP (for example) you can select “Rotate through events” so that it changes the filter between each exposure and you end up with a complete set of R/G/B images so long as you complete more than 3 exposures

I have both a full frame DSLR and a tiny ASI(1600MM) and the results are...different. On the same scope, the tiny sensor with the tiny pixels will give you better resolution on a good night, obviously at the expense of total FOV. It really depends on your angle...

The mono sensor is more versatile in that it can be effective with narrowband too...not impossible with a DSLR, but not optimal.

[Decimus (Richard)]

Originally Posted by Camelopardalis

And getting caught short with a mono sensor is easily avoidable...in SGP (for example) you can select “Rotate through events” so that it changes the filter between each exposure and you end up with a complete set of R/G/B images so long as you complete more than 3 exposures

I have both a full frame DSLR and a tiny ASI(1600MM) and the results are...different. On the same scope, the tiny sensor with the tiny pixels will give you better resolution on a good night, obviously at the expense of total FOV. It really depends on your angle...

The mono sensor is more versatile in that it can be effective with narrowband too...not impossible with a DSLR, but not optimal.

Thanks for your comments, Dunk. As you say and as I have been discovering, some small CCD sensors with small pixel size can indeed deliver better results than a full frame DSLR. Just makes choosing the right camera even more bewildering!

Cheers,
Richard

[Atmos (Colin)]

I’d suggest it comes down to whether you want a really wide field or narrower and higher resolution. If you want the wider field then a FF OSC can be the way to go where as if you want resolution then a smaller sensor is on the cards. A mono ASI1600/QHY163M or even a colour ASI183/QHY183.

[Camelopardalis (Dunk)]

Richard, it might help you if you decide on some targets that you’d like to go after, and go from there.

For large, sprawling nebulae, you might want the larger chip size, but for galaxy chasing the a small sensor with tiny pixels might be a more appropriate tool for the job (besides a larger scope!)

Hint: if you look in the imaging forum, some of the “old faithful” are joining the CMOS party. Not that there’s anything wrong with some of last gen CCDs, they’re just more expensive and not inherently superior to a good CMOS sensor...

And for your quoted budget, you can have a full frame DSLR _and_ a cooler CMOS camera

[Slawomir (Suavi)]

Originally Posted by Decimus

Thanks for your input and advice, Greg. I take your point about losing fine detail in nebulae with a colour CCD camera, but I suspect the QSI 683, magnificent as it is, will be a weighty set-up when laden with filters and could produce some tube flexure on my WO GT102? Hmm....Our weather down here is appalling and clear skies increasingly rare; hence my thinking about taking images quickly!

Have you any experience with Atik CCD cameras? Or Starlight Xpress Trius models? No one seems to talk about them and I am wondering how good they are.

Thanks again.
Cheers,
Richard

Hi Richard,

Some excellent advices were already given.

I used Atik 428ex and it was a nice camera, but I needed a more powerful cooling (and wanted a larger FOV), so I upgraded to QSI 690 WSG-8. It is quite heavy, with guide camera and filters the mass is about 1.6kg, but my standard focuser on TS 102 handled it well, so I suspect your WO should cope well too with this much mass hanging off it. Had my QSI for five years and although tempted by a larger real estate, I cannot see a worthy candidate for an upgrade at this stage. Low RE (measured 3.9e at -25C, 4e at -15C), high QE, no need for darks nor bias at all - when I experimented with my attempt at the Helix with 100+hrs of total exposure, darks + bias made measurable (in PixInsight) but not visible improvement, when stacking over 150 subs. These days I use 20min narrowband subs so I reach desirable for me SNR with about 30-40subs. With LRGB filters, a few minutes is plenty. I think this particular model of the camera really shines in narrowband when combined with a low to moderate focal lengths.

I would also check new offerings from Moravian cameras.

Regards
Suavi

[gregbradley]

Originally Posted by Decimus

Thanks, Colin. You have persuaded me to maybe save up for the QHY367. ( believe the QHY12 is also very good?) Failing that, the ASI071 may be a cheaper alternative.

Meanwhile, back to some imaging with the D850.

Cheers,
Richard

Now you’re talking Richard. That qhy367 is the go mate.
If I were tempted by a osc it’d be that one. How different
would it be compared with a D850 though? Stock D850?
A modded D850 perhaps although I would
check reviews for its use for Astro. Nikon seems
hit or miss for Astro. Some models are great and others -hmmm.
Nikon does some spatial filtering and they also wont do proper flats
as well as not a proper long exposure noise reduction. Again depending in the model.

SX Trius, yep not bad. Atik? - dont know.

Greg

[Atmos (Colin)]

Apparently the D850/Z7 has a lower QE than the D810A/QHY367/ASI094 but I get 14-bits of dynamic range which is better than the KAF16803 with 3.1e- read noise.
It’s a good chip

[Camelopardalis (Dunk)]

The troubling thing with the new Nikon mirrorless cameras are the reports of fixed pattern when pushing the shadows, that doesn’t exist in their DSLRs.

The spatial filtering is also a concern, if it can’t be disabled. This is less severe than Sony’s star eater, but it’s still monkeying with the signal...

[billdan (Bill)]

If you don't mind buying a second hand OSC, there is a QHY10 (APSC 6 micron pixels CCD) for sale and a QHY168 (APSC 4.8 micron pixels CMOS) for sale in the IIS classifieds, both at reasonable prices.