Back in November last year, I became aware that ZWO were making a range of cooled imaging cameras based on Sony sensors. Initially I was thinking of getting the ASI174MM-cooled as it is a reasonably sized sensor with global shutter. But after reading about the other cameras in the line up, I decided to pre-order the ASI178MM-cooled, as it has smaller pixels – great for planetary imaging and also for deep sky objects with a fast telescope. This camera finally arrived on Tuesday.
Why buy the ASI178MM-cooled imaging camera?
- Very reasonable price at US$699. I managed to get it for less by pre-ordering it before 31/12/15.
- Great back-illuminated CMOS mono sensor which has high resolution 6.4 megapixels, which can be used for ultraviolet, H-alpha solar, planetary and deep sky object imaging – all in one camera. No Bayer matrix means its sensitivity to UV is much higher than traditional colour sensors*.
- Very low read noise (2.2 e), high sensitivity.
- Cooled sensor which can go below ambient temperature by 35-40 degrees Celsius.
- USB 3.0 port allows for faster data transfer for even faster frame rates – particularly important for planetary imaging.
*Do note that to get maximum transmission for UV, the AR coated window (cut at 350nm) needs to be replaced with a Quartz or Fused silica window – I have enquired with ZWO regarding such as window, as I believe that could make ZWO cameras more useful for UV imaging of Venus or of flowers in UV.
I have to say that this camera looks very impressive indeed, does not feel too heavy but is very nicely constructed. And it looks great – I do like the red. Interestingly there is no indication of which camera this is on the actual camera body – it is only looking at the size of the sensor which gives you a clue (and what the camera is recognised as by the imaging program such as Sharpcap) as to which camera you have.
In order to cool the sensor down, it is recommended to use a 12V 2A DC adapter, which I happen to have one handy at home, so no need for any further outlay.
And look at those fins which dominates most of the casing – all allowing for the heat to be dissipated to cool down that sensor and reduce dark noise.
It comes with the accessories you see below. Of note, there is a pack of 4 desiccant tablets available to replace the ones in the imager should the sensor start to dew over; this should be unlikely to happen for many years as the sensor compartment is sealed. But should this be necessary, it should be possible to buy spares from ZWO.
I have mounted this camera to my Xagyl filter wheel, as I will be using the Astronomik LRGB filters for imaging.
This 1/1.8″ sensor is equivalent to 4.8x crop factor from 35mm full frame. Hence the focal length of the telescope used will be multiplied by 4.8x – that should allow for deep sky imaging even with shorter focal length telescopes or fast camera lenses.
Sensor: 1/1.8″ Sony Starvis CMOS IMX178 mono
Resolution: 6.4 megapixels (3096 x 2080)
Pixel size: 2.4 micron
Sensor size: 7.4mm x 5mm (4.8x crop)
Exposure range: 32 microseconds – 1000 seconds
Back focus distance: 17.5mm
Shutter type: Rolling shutter
Max fps: 3096×2080 (60fps/30fps)