In this ZWO ASI585mc review, I’m going to tell you my thoughts about this camera. It is a dedicated astronomy camera without cooling. Now, versions with cooling are real game changers. The quality a cooled camera can produce are excellent. However, cooled dedicated astronomy camera’s often come at a cost that’s prohibitive to many.
So with that in mind, I specifically asked First Light Optics for this uncooled ZWO ASI585mc. I’ve had the camera for a while now and I’ve taken some images. It’s time to share my thoughts for with this camera in case you’re looking to buy one. This article will help your decision making.
Quick Links
Sensor
First thing with any camera is it’s sensor, so I’ll start there.
The ZWO ASI585mc uses a Sony IMX585 chip and has 8.3 megapixels. The image sizes are 3840 x 2160. 8 Megapixels may not sound much, especially compared to modern DSLR or mirrorless cameras but it’s still plenty for astrophotography.
This sensor’s Quantum Efficiency peak is 91%. That’s a fancy way of saying how efficiently it can use the light hitting the sensor. At 2.9 micro pixels means the chip itself is really quite small. This is important for deciding on suitability for focal lengths but I’ll tell you about that later.
The active sensor size is 11.4mm x 6.26mm. This means your telescope will have a Crop Factor of 3.2x when compared to a full frame DSLR.
Field of View
So why is that Crop Factor important? It’s a lot of numbers, but it basically means it affects how much your camera and telescope will see. The Field of View.
Field of View is the relationship between your focal length and the chip size of the camera. As the ZWO ASI585mc has a small sensor, it will – for lack of better words – zoom in more. This is something to consider as the camera chip size will directly change how your telescope behaves.
Even a wide field telescope will suddenly feel much more zoomed in.
Look at this example of some Field of Views:
- 1000mm telescope with a full-frame camera (Red)
- 1000mm telescope with the ZWO ASI585mc (Purple)
- 3200mm telescope with a full-frame camera (Orange)
You can use this to your advantage if you want. Zooming in more without having to buy a new telescope can breathe some new life into your current telescope. Also this tiny sensor and large crop factor means the ZWO ASI585mc is suitable as a Lunar, Solar and Planetary camera.
Is this a downside? Is it a benefit? That’s up to your interpretation. I personally really enjoyed the smaller field of view on my Sky-Watcher Evostar 80ED when I used it to image the Elephant’s Trunk Nebula.
Suitability Of The ZWO ASI585mc
Every camera sensor has a focal length range it operates best at. We call it sampling. Considering this camera has small pixels at 2.9um, it tells me it’s better for wider focal lengths.
Using Astronomy.tools we can calculate its best range is about 300mm to 890mm for Deep-Sky Astrophotography. So this is, in theory, its sweet spot producing the best images and no square stars and also ability to pick up fine detail.
Bare in mind, that’s the focal lengths AFTER any barlows or reducers.
That’s not to say it can’t be used with longer focal lengths. Small chips are often combined with very long telescopes for planetary and lunar work. It creates oversampling, which is useful for high magnification high resolution solar system work.
If you want more information about imaging planets, watch this video by Damian Peach on High Resolution Planetary Photography.
So let’s look at some examples from Stellarium that would sample nicely with this camera.
- 300mm you can squeeze in the Orion Nebula or the Eagle Nebula
- 500mm fits the Triangulum Galaxy M33 nicely
ZWO ASI585mc Images
The following images are only 1 hour of integration time, taken through an Antlia ALP-T Dual 5nm Narrowband Filter and the Sky-Watcher Evostar 80ED.
Using The ZWO ASI585mc
So I’ve enjoyed the camera and the pictures coming out have been quite clean for its size and not being cooled. But nothing’s perfect and I have found some niggles.
That small sensor is entirely up to you whether you like it or not. But it will make a drastic change to your telescope’s field of view. It won’t catch as much light as larger sensors either which can cause more noise.
The back distance to the sensor is 17.5mm but the uncooled version doesn’t have any adaptors for spacing. Chances are you won’t need them due to the small sensor. But it’s better to have them and not need them rather than need them and not have them. Most reducers and flatteners like 55mm from the reducer to the sensor.
The tiny chip will use the theoretical best part of your telescope – the centre. Though every setup is different. If you need adaptors, they’re sold separately.
ZWO ASI585mc Full Wells
The other niggle is the constant misconception of full wells. Yes, they have 40000 electron full wells at the lowest gain. But at Unity Gain, where the vast majority of us image, they’re 4000 electrons. In plain speak this means how much light the pixel can see before it just turns white and all detail is lost.
I would avoid doing very long exposures with this camera. That’s what I’m saying. Especially on bright targets. Narrowband works, but again I’d recommend against 10 minute exposures. And look out for targets with bright stars in the frame like the Horsehead Nebula and Alnitak.
These days most cameras come with no amp glow – or starbursting at the edges. I’m pleased to report the 585mc is no different. The images are nice and clean and post processing is easier.
Another benefit is its physical size is small so doesn’t add much weight. The fact it doesn’t need external power to operate a cooler either means it can be used from the ASIAir or even a USB from a laptop wherever you go, if you head out to remote sites etc.
Pricing and Conclusions
At the time of this review, the uncooled ZWO ASI585mc costs £382 from First Light Optics. If you fancy spending a bit more, the cooled ZWO ASI585mc Pro version is £619.
Not only is this capable of deep sky targets and imaging, including some narrowband with a mutli-bandpass filter. But it’s also already set up for planetary work and can hit up to 26 frames per second.
It’s a well priced, sensitive and versatile little camera that can turn its hand to just about every facet of telescopic astrophotography. Bare in mind that Field of View and use tools like Stellarium and Astronomy.Tools.
Feel free to download some sample images I’ve taken and assess the data yourself. Please credit me if you share them on social media.
I hope this review of the ZWO ASI585mc was helpful for you, let me know your thoughts of the ZWO ASI585mc in the comments below. Thank you for your time reading.
Clear skies to you, keep looking up and keep them cameras clicking.