It’s smaller, lighter, and cheaper than the bigger ASIAir Plus astrophoto computer, but is it as good? I test ZWO’s new ASIAir Mini.
It is safe to say that products from ZWO, a company based in Suzhou, China, have revolutionized astrophotography worldwide. At the heart of their product line, and of any astrophoto rig incorporating ZWO products, is the ASIAir mini-computer.
The Air allows programming everything in your imaging setup with a device that is easy to power and use at the telescope. One app on a mobile device (iOS or Android) is all you need to control a camera, autoguider, GoTo mount, and any ZWO accessories such as filter wheels and motorized focusers.
Because your phone or tablet communicates with the Air via its WiFi, it is possible to operate an astrophoto system wirelessly from the comfort of your warm car or home.
A Succession of Airs
I reviewed the second-generation ASIAir Pro for AstroGearToday here, though just for use as an autoguider controller as at the time in early 2021 the ASIAir firmware did not support the Canon mirrorless cameras I use.
The Pro was superseded in August 2021 by the ASIAir Plus, reviewed for AGT by Lee Pullen here. The Plus corrected the older Pro’s main deficiency – its limited WiFi range – by adding an external antenna, which the ASIAirs should have had all along.
Introduced in October 2022, the Mini offers most of the features of the Plus, including the essential antenna, but in a smaller case and, at $199, at a price $100 cheaper than the $299 ASIAir Plus.
In my testing, I found the Mini worked very well. I didn’t miss or need the features it lacks compared to the larger, more costly Plus.
Setting Up the Air Mini
While the Mini comes with a small instruction pamphlet in English and Chinese, it is brief and fails to mention the need to enter a password when connecting to the Air for the first time, nor where you find it (it is on a sticker on the bottom of the Air). First time users could get stymied at step one!
However, the pamphlet does describe the subsequent activation, an initial one-time process that went smoothly.
The older ASIAir Pro held its operating system on a removable MicroSD card, which risked the Air not booting should the card become damaged or corrupted. The newer Plus and the Mini both use an internal eMMC (Embedded Multi Media Card) for the operating system and user files, for more robustness.
While images can be saved to the eMMC, I elected to also save the Canon CR3 raw files to my camera’s own SD card. It is also possible to save images to a Windows-formatted memory stick inserted into one of the USB ports instead of to the eMMC.
The Air Mini Hardware
As with ZWO’s other Air models, no power supply is included with the Mini. It is assumed the user has one. Any 12-volt battery or AC-to-12-volt DC power supply will work. But if it is to power both the Air and other devices, it needs to have sufficient output of 3 to 5 amps.
The supplied power cables can be used to distribute 12 volts from the centrally located ASIAir to other 12-volt devices such as ZWO cameras (maybe!), filter wheels, and focusers. (I tested the Mini with a ZWO autoguider only, plus mounts from Astro-Physics and Sky-Watcher, and Canon cameras.)
With the Air acting as a power distribution box, only one power cable needs to run from the power supply, likely located off the mount, to the Air, which would be riding on the scope, minimizing cable snags as the telescope moves around.
In theory, the Air could also be used to send power to the mount. But GoTo mounts can be notoriously demanding of power. The Mini’s maximum total output from its four DC power ports is just 3 amps. A GoTo mount alone can draw that much when slewing. Even ZWO’s own AM-5 mount can draw 5 amps.
Sky-Watcher, for example, specifically warns users not to power their mounts via any ASIAir, but only directly from a 12-volt source. Operating one of their mounts with inadequate power can actually damage the mount. In my case, trying to power my Astro-Physics mounts via the Air failed – the mount’s hand controller booted but refused to move the mount.
The same applies to cooled CMOS cameras. ZWO’s models can draw 5 amps with the cooler on, and so demand their own power supply. Thus, the Mini’s power outlets will be of limited use. But that’s also true of the Plus, as its maximum throughput is also 3 amps.
However, I found no issues powering a 12-volt anti-dew heater band via the Mini while also having a guidescope and Canon camera attached via USB cables.
With the bigger ASIAir Plus, its four power outputs can be switched on and monitored individually. With the Mini, all outputs are always on, with no individual control or statistics.
As an alternative, if all you are powering is the Mini itself with devices connected only to its USB ports and not to its power ports, it is possible to power the Mini from any 5-volt power bank (such as used to charge a phone) via the USB-C port on the side of the Mini. This works well, say, for just auto-guiding, but precludes using the Mini’s power outputs to distribute 12 volts to other accessories.
And yet, oddly, despite the Mini’s ability to run from a 5-volt source, I found that when powering it from a 12-volt battery, if the input voltage dropped much below 10 volts the Mini shut itself off, abruptly ending a session.
Connecting the Air Mini
While several power cables come with the Mini, no USB data cables are supplied. In setting up my gear, I had to fish through my drawer of umpteen cables to find the right ones to go from the Mini to my Canon camera, and from the Mini to the mount.
For those with older Sky-Watcher mounts or hand controllers lacking a USB port, the solution for mount control is to buy a so-called “EQMod” cable (available on Amazon) for your mount model that goes from USB-A into the RJ45 port where the hand controller plugs in. So, the Air replaces the hand controller. I did not test this configuration.
A hardware feature missing from the Mini is an ethernet port, negating the option to connect it to a WiFi extender to boost its signal range.
In practice, however, I found the Mini’s signal strength good enough to maintain a solid connection to my iPad even when it was inside my house some 50 feet from the scope and Mini in the backyard. That’s per the advertised spec and a huge improvement over the now-discontinued ASIAir Pro, which worked only within a few feet of the scope.
However, at greater distances from the Mini images took four to five times longer (up to 30 seconds) to download and display compared to when the iPad was close to the Mini.
The Air Software
As with any ASIAir, to run the Mini you need to download the free ASIAir app from either the Apple App Store (for the iOS version) or Google Play store (for the Android version). I tested the iOS version. Firmware updates for any of the ASIAirs are applied through the app.
I initially tested the Mini with v2.0 of the app, then v2.1.1, with v2.x being a major update from v1.x. The app ran fine on my iPhone and iPad, though to get the phone to recognize the Mini I had to turn off “Cellular Data” in the phone’s settings. That’s a common glitch with the app. Leave Cellular Data turned on and while the phone will see and connect to the Mini’s WiFi network, the app will still insist there’s no device present to connect to.
No instruction manual is supplied or available for the current v2.x app, a major deficiency. The PDF file downloadable from ZWO’s website is outdated, as it describes the older ASIAir Pro and operation of the software as it was in early 2020.
ZWO’s marketing suggests that operating an ASIAir is “As Easy As 1-2-3.” I feel that’s a bit of a stretch. Even as an experienced astrophotographer I find the app can be confusing to navigate at first. But like any software, you get used to its quirks.
To access the app’s object lists and exposure planning modes, perhaps to set up a plan by day for the coming night, you must have your camera connected, a nuisance if your system is set up outside. The star atlas, which is based on the open-source Stellarium app, also defaults to the current time and can’t be set to a later time for that night.
There are no help pages embedded in the app that you can call up. While most of the app’s features can be figured out by fumbling around on your own, I suspect most beginners will rely on YouTube experts to provide tutorials. I know I did!
When a mount is connected to one of the Mini’s USB ports, auto-guiding is handled through the USB connection rather than via the mount’s ST-4 autoguider port, though that mode is also an option.
For cooled CMOS astro cameras, only ZWO branded cameras are supported. But all the Airs, including the Mini, will control a wide range of Canon, Nikon and, as of March 2023, Sony cameras. The Mini worked well with all my Canon mirrorless cameras. I could not test it with a Nikon or Sony.
With a camera connected, the Air can control the camera’s exposures in sync with the autoguiding to perform “dithering.” This function allows the Air to shift the mount’s position by a few pixels between each exposure, then resume autoguiding. This is helpful for averaging out thermal noise hot pixels later when stacking images.
With the Mini, autoguiding and dithering worked very well, with the time between exposures much shorter once I reduced the “Timeout” from the default of 60 seconds to 30.
When a mount is connected, the Mini issues the GoTo commands. Upon arrival at a target, the app will “plate solve” by taking an image to determine exactly where the scope is pointed in order to perform a precise final framing. This worked well with the Mini, though sometimes with long delays between each iteration.
Air Mini Recommendations
Confusingly, ZWO seems to now have two websites: the older https://astronomy-imaging-camera.com/ and the newer, more polished-looking https://www.zwoastro.com/.
As of early March 2023, the latter site describes only the larger ASIAir Plus, not the Mini, though the Mini is offered as an option after clicking the Buy Now button. However, many dealers offer ZWO products where the product distinction is clearer. Even so, be careful you don’t order the $300 ASIAir Plus by mistake if it’s really the Mini you want.
But is it the Mini you want? If you prefer to have full control over power distribution, or plan to do planetary imaging requiring faster USB 3.0 ports, or want to “live stack” images from high megapixel cameras, then the ASIAir Plus is the one to get.
However, I think for most users the Mini will be more than sufficient for deep-sky imaging, offering all the key features needed. Its lower cost and smaller size are advantages when assembling an entry-level and portable astrophoto rig.
If you have an older ASIAir Pro, especially the original plastic cased ASIAir from 2018, upgrading to the Mini will get you the major benefits of the eMMC storage and external antenna with its greater WiFi range. It was for those reasons I purchased the Mini to replace my Pro.
Even if all you want is an autoguider, the combination of the ASIAir Mini ($199) coupled with ZWO’s 30mm Mini Guide scope ($99) and their ASI120MM guide camera ($149) makes for one of the best and most affordable solutions available. This combination allows expanding your rig’s capabilities by adding camera and mount control later when needed just by adding the right USB cables and learning the app’s many options.
I can recommend the new ASIAir Mini, especially for cost-conscious beginners or anyone assembling a compact deep-sky imaging system.
Plus
Provides central control of auto-guiders, cameras, and mounts
Offers most features of the very powerful ASIAir app
External antenna for good WiFi range
Very small, light, and affordable
Minus
Lack of current documentation for the ASIAir app
No independent control of 12-volt outputs
Limited power throughput
Sensitive to low input voltage
Retail Price: $199.00
Website: https://astronomy-imaging-camera.com/product/asiair-mini
