In Ye Olden Days, observers heading out on a clear night had to take with them a bulky star atlas and maybe a Moon chart. But if you’re an amateur astronomer, they are also pocket computers that allow you not just to plan observing sessions in advance but enhance your enjoyment of and maximize your productivity during them. Today’s smartphones are essentially tricorder-like computers that occasionally - and inconveniently - make a weird noise or vibrate when someone wants to talk to you in real time. Why? Because there are now so many useful apps available for them that they are, I think, an essential a part of the amateur astronomer’s toolbox.

In recent years, another item has been added to that list for many (but not all) observers: a smartphone. If you have a pair of binoculars or a telescope to zoom in on those things, well, so much the better, but they’re not essential. You need a clear night, somewhere dark, and at least a basic knowledge of the night sky so you can hop from star to star and constellation to constellation to find interesting things like star clusters, galaxies, and planets.

In fact, the list of things you actually need if you want to go skywatching these days is pretty much the same as when I started out in this hobby 40 years ago. It’s easy to get the impression that if you want to look at the night sky, you have to live out in the desert and have either a telescope covered with so many wires and leads that it looks like someone has thrown a bowl of spaghetti over it, or a camera powerful enough to photograph Perseverence driving across Mars.

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