Vincent van Gogh's The Starry Night has always been one of my favorite paintings, and it may even be partly responsible for my love of night-time astrophotography. But I always assumed that beautiful swirling sky was mostly a product of his imagination. Turns out, it may have been based on a very real sky on a very specific night. 

A team of astronomers used what they call "forensic astronomy" to compare the painting with astronomical simulations, historical weather records, star positions and Vincent van Gogh's letters. They concluded that the celestial arrangement in The Starry Night closely matches the predawn sky over Saint-Rémy-de-Provence, France, around July 22, 1889. 

That date is interesting because art historians have traditionally placed the painting in June 1889. But there was a problem with that theory: the moon in mid-June didn't match the thin crescent van Gogh painted. The new analysis also identifies the prominent group of stars in the painting as the Hyades star cluster in Taurus, rather than Aries, as earlier researchers had proposed. 

That doesn't mean van Gogh was simply painting the night sky like a photograph. Parts of the scene were clearly shaped by his imagination and distinctive style. But the research makes a fascinating case that beneath those famous swirls was something very real. More than 130 years later, astronomers may have figured out what van Gogh was actually looking at when inspiration struck.