Like many astroimagers, I have a long and storied history of cameras. I started with my beloved Nikon D700 DSLR, before testing the dedicated astrocamera waters with an iNova NNB-Cx. This confirmed I was hooked, so I bought a QHY8L OSC, which led me to a ZWO ASI1600MM Pro. That camera was great, but Mono didn’t suit my skies or available time, so I sold it and hopped on over to the world of OSC with a ZWO ASI2600MC Pro. This proved to be a wise decision, because OSC is a valid option from a city, and the camera is flippin’ awesome. I’ve been using mine for almost a year, so think it’s time for a review…
Build quality
The ASI2600MC Pro is well-built. It weighs 1.54lbs (700g) and feels like a reassuringly hefty piece of metal and circuit boards when held in your hand.
The camera’s back is dominated by a large fan, which can cool the sensor to 35-degrees below ambient temperature. (I run mine at -10 degrees C). This is useful to lower noise levels, but perhaps more importantly allows you to create a library of calibration frames at a set temperature that you can then re-use. This is a big time-saver. The fan needs a lot of juice to run, so it has its own dedicated power port on the back of the camera.
Also on the back is a USB3.0 port to hook the camera up to your controller of choice – I recommend an ASIAIR Plus. As a bonus, there are even two USB2.0 out ports, meaning the camera can act as a hub for other accessories. I use mine with a ZWO Electronic Autofocusser. Oh, and the sensor has a little heater to stop it frosting over. Very useful!
Star of the show
The ASI2600MC Pro’s sensor is the star of the show. It’s APS-C sized (23.5 x 15.7mm), which is large enough to give wide fields of view, but not so big as to be particularly taxing on your telescope’s optics. If you do want a bigger sensor, then the next step up would be the ASI6200MC Pro. This has very similar specifications to the ASI2600MC Pro, but the sensor is full-frame, i.e. even larger. You’ll need a bigger budget and a fancy telescope to make the most of it, though!
Back to the sensor. It has a resolution of 6248×4176, which is ample to give good detail of most targets, and even affords enough headroom to do some serious cropping if needed. It also boasts a dynamic range of 14 stops, leading to smooth images with excellent contrast.
The sensor is also very sensitive, with a Quantum Efficiency (QE) – a measure of how effective a sensor is at converting photons of light into recorded signal – in the 80 to 90% range. For reference, the older but still popular ASI1600-series have a QE of around 60%. The QE of DSLR and Mirrorless cameras varies a lot, but think around 30 to 50% and you’ll probably be in the right ballpark.
Noise levels are low but certainly not non-existent. Some users forego Bias and Dark frames, but I still throw them into the mix and find that they help. PixInsight seems to like Bias frames to calibrate Flats, at any rate. I tried Dark Flats but the results weren’t good. As ever, my advice is to try different combinations for yourself.
Hurrah for CMOS!
Back in the days of older-style CCD sensors, you needed to shoot sub-frames that were fairly long: 10 or 20 minutes, perhaps more. The ASI2600MC Pro’s sensor is a modern CMOS type, and works differently. In practise this means you can shoot much shorter subs – perhaps even mere seconds, depending on your sky conditions. For the technical reasons why this is the case check out this video: Deep Sky Astrophotography With CMOS Cameras by Dr Robin Glover.
You still want a long total integration time to have strong signal in your final image, which is especially important to combat light pollution, but with the ASI2600MC Pro you’ve got flexibility in how you get there. Check out this article on how to get long integration times for more details. I shoot 2-minute subs as standard, and aim for total integration times of around 20 hours per image. This works well for my Bortle 8 skies.
The camera pairs nicely with a dual-band filter like the Optolong L-eXtreme. I’d consider this a must if you’re imaging from a city, as with it you can shoot hydrogen-rich deep sky objects and mostly bypass light pollution. For broadband targets I don’t use any filter, for reasons explained in my light pollution filter shootout.
What’s the catch?
The images are a whopping 50MB each. This necessitates a lot of hard disk storage, and if you’re stacking many hundreds of images – which I hope you are – you’ll benefit from a beefy computer to do the heavy lifting during image processing.
And then there’s the price: £1899 ain’t cheap. For what you get, though, it’s good value.
For more example photos, check out my gallery.
Spare a penny, guv’nor?
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