Smart stargazing A beginner's guide

Curious about smart telescopes? Jamie Carter has the low-down on the app-powered tech that's making deep-space imaging easier than ever

- Jamie Carter

Imagine this: you set up a small telescope in your back garden. On your phone's screen, you tap on the Orion Nebula. Seconds later, the scope slews to it, focuses and begins revealing the colourful swirling gas and dust from 1,300 lightyears away – even though you live in the middle of a light-polluted city.

That's the promise of the new wave of smart telescopes. They're compact, app-controlled, robotic observatories that are more like mini versions of the professional telescopes perched on mountaintops in Chile or Hawaii than the refractors and reflectors that have long been at the heart of amateur astronomy.

A smart telescope is a motorised telescope with an integrated camera and onboard computer. In some ways, these fully contained units are similar to the motorised Go-To telescopes that have been around for decades, but here everything is more digital – and less optical. They're available as refractors and reflectors, in various shapes and sizes, but what they all do is focus the light they collect onto a CMOS sensor, like those found in smartphones (and initially created for use in NASA spacecraft).

Once light reaches the sensor, the onboard computer takes over. Using a process called plate solving, the telescope matches the pattern of stars it sees to a celestial catalogue, determining precisely what it's looking at. It can then slew automatically to selected deep-sky targets, track them precisely and build up detailed images by stacking many short exposures. Sophisticated image-processing algorithms enhance contrast, bring out subtle colours and suppress the effects of light pollution. It's the same process used by deep-sky astrophotographers who assemble their own rigs by putting CMOS cameras on telescopes – but with smart scopes, the entire process is automated.