When Raspberry Pi devices appeared, we were excited by their potential to simplify astrophotography and the ZWO ASIair has been developed to do just that.
The package we are reviewing is a ‘bundle’ that includes a 30F4 mini guide scope and ASI120 guide camera.
The ASIair is lightweight and compact, and designed to be fitted on or near to your telescope with hook and loop pads.
With so many useful features it is difficult to accurately describe its functions in just a few words, but basically it is a stand-alone computer that can control ZWO cameras and a filter wheel, provide Wi-Fi connectivity to a mount, and auto-guiding.
A 12V DC supply is required to power the ASIair’s 5V converter and, once turned on, the ASIair establishes its own local Wi-Fi, either 5G for faster communication or 2.4G for greater range.
Smartphone or tablet users can then connect directly to the ASIair via the downloadable ZWO ASIair app.
Best of all worlds
The unit is compatible with most popular telescopic mounts, including Celestron and Sky-Watcher.
These can in turn be controlled using a smartphone or tablet, thanks to integration with SkySafari, a popular planetarium app.
We connected our 10 Micron mount with the supplied RS232 cable, and within a few moments were able to simply tap on targets within the SkySafari app and the mount happily slewed to them.
Typical mount handsets can be clunky to use and require repeated button pressing and menu navigation, not to mention the trailing cables.
They always seem to end up snagging on something, so the ability to stand back from the mount and simply click your next target on a phone screen is probably reason enough to invest in an ASIair unit.
But it is capable of much more, as we discovered.
All ZWO USB3.0 cameras, cooled cameras and ASI mini cameras are recognised by the ASIair.
Our supplier kindly made an ASI294MC camera available to test the imaging capability of the system.
Before starting the imaging run though we set up the 30F4 guidescope, attaching it to our telescope, along with the ASI120MM Mini camera.
There are four USB2.0 ports on the rear of the ASIair and the cameras were immediately recognised, with all their key characteristics available to the control app.
The guide camera has a USB-C (24-pin) connection, along with an ST4 connection if required.
We were impressed with the sheer simplicity of setting it all up; astrophotography is so much more rewarding when the technology just works.
Opening up the autoguiding interface revealed a familiar setting, as PHD2 scope-guiding software is incorporated into the app.
After finding a suitable guide star we started the calibration process. A short while later, as autoguiding began to work, our attention turned to the imaging process itself.
Controlling the imaging camera is straightforward; just choose whether Light, Dark, Bias or Flat frames are required.
Next, set the exposure time and number of pictures to take and hit the go button. This is hassle-free astroimaging with no laptop required.
The pictures taken are saved on to a 32GB SD card, and can be transferred to a computer for processing, either by removing the SD card from the ASIair and using the supplied USB adaptor, or via Wi-Fi or Ethernet.
The operating system for the ASIair is installed on the SD card. Basic instructions are provided but remember to take care when first using the equipment and to make a backup of the software.
Once everything was set up and running, the guiding was moving along happily and the images were being taken and saved, with a progress report displayed live on our phone.
We even wandered away from the equipment, out of range of the Wi-Fi signal. When we returned the connection automatically refreshed itself and brought the app on our phone up to speed with what the camera had been doing while we were away, again, the process was seamless.
If you already have the appropriate ZWO cameras then the ASIair and auto-guiding bundle really simplifies astrophotography, making it easy to control everything using the phone in your pocket.
Not only is the ASIair unit itself nicely made, the app that controls it is slick, well designed, and simple to use.
Astronomy software can become complicated and having to navigate overly technical applications in the dark with cold hands is fairly daunting.
This app is a pleasure to use and provides almost everything you need to know on one screen, including image progress, guiding graph and image preview.
There’s a histogram stretch, to give an idea of how much faint signal the camera is collecting. Colour images can also be debayered – where colour filters are adjusted – while you are on the move.
The ASIair app runs on recent Android and iOS devices. When tested, it ran smoothly on a recent smartphone and an older Android tablet. It would have been nice to see a night vision mode with red controls.
The ASIair could be used at public astronomy events, displaying the object the scope is trained on easily for all to see on a screen, without hindrance of cables.
30F4 Mini guidescope
Mounted on a standard finder-scope shoe, this 30mm, f/4 scope has a helical focusing method with 20mm of travel. Lightweight and extremely compact, it nonetheless provides a clear, wide image of the sky for plenty of guide star options without adding too much weight. There are two thumbscrews for holding a 1.25-inch camera.
The lightweight ASIair unit provides four USB2.0 ports, ethernet connection, and an SD memory card slot, with a 32GB SD card included. It is powered by the supplied 5V USB lead, using a 12V DC power source (not supplied) and establishes a local 5G or 2.4G Wi-Fi within seconds of being switched on.
ASI120MM mini camera
Nicely matched to the guidescope, the monochrome ASI120MM Mini camera has 1280X960 resolution, with a 12-bit ADC (analogue to digital converter) and can be used as a planetary or lunar camera in its own right. As a guide camera we found it to be amply sensitive using a medium gain setting, with images demonstrating low read noise.
Accurately focused images are essential for good quality results. Within the ASIair app there is a focusing assistant tool which allows coarse and fine adjustments and displays the results as a numerical value. Alternatively, the live view star image displayed on a phone or tablet works well with Bahtinov mask focusing, a diffraction-based technique.
The off-line plate solving function works by comparing an image of the sky taken by the camera against a database, and accurately identifying the mount’s position. After syncing the mount accordingly, the Go-To positioning accuracy of the mount will be improved, allowing targets to be located more effectively.
- Price: £381
- Guidescope: 30mm objective lens; 120mm focal length; 1.25-inch fitting
- Guide camera: USB2.0 CMOS camera, 1/3-inch-sensor, 1280×960 resolution
- Main unit: ZWO ASIair Smart Wi-Fi unit, including SkySafari bridge with ASI USB3.0 camera control
- Weight: 500g
- Extras: Hook and loop mounting pads, SD card reader, USB-RS232 cable, short USB cable
- Supplier: 365 Astronomy
- Tel: 020 33 845 187
This review originally appeared in the May 2019 issue of BBC Sky at Night Magazine