What it actually is

An ASIAir is a small Linux computer with a handful of USB ports, a 12 volt input, a few switched power outputs and its own Wi-Fi radio. It sits on the telescope, everything else plugs into it, and you control the entire rig from a phone or tablet. That is the whole idea. It replaces the laptop, the extension lead, the folding table and the long trailing cable that used to run back to the house.

It matters more than it sounds. Almost every session I have lost was lost to something mundane — a USB cable working loose in the cold, a laptop lid closing, a hub dropping a device mid-run. Shortening the cable runs to a few centimetres on the scope itself removes most of that class of failure at a stroke.

Everything hangs off one box, and the box talks to your phone phone or tablet Wi-Fi — no cable needed ASIAir control box + storage one 12 V input Mount Main camera Electronic focuser Guide camera Dew heater goto, tracking, meridian flip exposures, cooling, storage autofocus by V-curve guiding and dithering switched 12 V, kept warm all night
The blue lines are short cables that live on the telescope. The only thing running back to the ground is power. On my own rig the controller, main sensor and guide sensor are all inside the ASI585MC Air, so three of those boxes collapse into one.

A night, in the order it happens

The app is arranged around the sequence a session actually follows, which is the reason it is quick to learn even if you have never used capture software before.

How a session runs, start to finish Polar align Plate solve Autofocus Frame Autorun Flip & finish on-screen, ~5 min then goto target EAF V-curve rotate, re-solve lights + dithering then darks & flats this is the part you sleep through
Only the first four stages need you awake. Autorun handles the rest, including the meridian flip, and will re-solve and re-centre afterwards so the framing survives the flip.

Polar alignment

The routine takes two exposures a set distance apart in right ascension, plate-solves both, works out where your polar axis actually points and then draws live arrows telling you which way to turn the altitude and azimuth bolts. It does not need Polaris to be visible, which is the single most useful thing about it if you image from a balcony with an obstructed north.

Plate solving and goto

Plate solving is the feature that changes the hobby. The camera takes a short exposure, the software identifies the star pattern against a catalogue, and the mount then knows precisely where it is pointing rather than where it believes it is pointing. Ask for a target, and it will slew, solve, correct and re-solve until the object is on the pixel you asked for. Star alignment routines, hand controllers and finder scopes all become optional.

Autofocus

With an electronic focuser attached, the ASIAir steps the focuser through a range of positions, measures star size at each, fits a V-curve and returns to the minimum. It takes about a minute and it is more accurate than I am with a Bahtinov mask. More to the point it can be set to repeat automatically every hour or after a given temperature drop, which is what actually keeps a long night sharp — a refractor moves focus measurably as the tube cools.

Autorun, guiding and dithering

Autorun is the plan: a list of exposures, a count, a filter, and optionally several targets in sequence. Guiding runs alongside it, making small corrections from the guide sensor, and dithering nudges the mount a few pixels between frames so that fixed sensor noise lands in a different place each time and averages away during stacking. Dithering is free and it is the cheapest noise reduction available; leave it on.

Where it is strong, and where it is not

The strength is integration. Everything talks to everything else, nothing needs configuring, and there is no driver layer to go wrong. Frames are written to the onboard storage, so a phone going flat or wandering out of range does not stop the run — the box carries on regardless, which is exactly what you want at three in the morning.

The cost of that is a closed ecosystem. It expects ZWO cameras, and it supports a defined list of mounts and accessories rather than anything that speaks ASCOM. If you already own a camera from another manufacturer, this is not the controller for you, and a mini PC running NINA will be more flexible and considerably more work. It is a deliberate trade: less choice, far fewer things to debug in the dark.

Four things worth knowing before your first night

  • Station mode is better than the default. Out of the box the ASIAir broadcasts its own network, which means your phone leaves your home Wi-Fi to connect to it. Joining it to your house network instead lets you keep both, and lets you check on a run from inside.
  • Give it a proper power supply. A single 12 V feed runs the controller, a cooled camera, the mount and the dew heaters. Undersized supplies cause failures that look like software faults, especially when cooling and slewing happen at the same time.
  • Take flats before you take anything down. The moment the camera rotates in the focuser, that night's flats stop matching. It is a two-minute job at the end of the session and it saves a re-shoot.
  • Copy the data off before the card fills. The onboard storage is generous but not infinite, and a night of short subframes fills it faster than expected.

Everything in the recent gallery was captured this way, on the Askar V riding the Juwei 14. Once the sequence is running the work moves indoors, which is where Siril takes over.