In an era of giant telescopes scouring the sky from both the ground and in space, one could be forgiven for thinking there wasn’t much left for an enthusiastic hobbyist to discover. But with patience and the right equipment, even an amateur astronomer can stumble on to an undiscovered galaxy.
From the dark skies of Pollino National Park in southern Italy, Giuseppe Donatiello had been investigating the Andromeda Galaxy with his home-built telescope, looking for previously reported dwarf galaxies and stellar streams.
In images acquired late in 2010 and 2013, Donatiello noticed an unidentified smudge of light. That smudge turned out to be a dwarf spheroidal galaxy — now dubbed Donatiello I — lurking on the far side of Andromeda.