Hydra, the water snake, is the largest of all the constellations — and by far the longest. It spans more than 100 degrees — almost a third of the way around the sky. So it takes a long time to climb into view. Tonight, for example, its head is in the east-southeast at nightfall. It’s well to the left of Sirius, the brightest star in the night sky. But the snake’s tail won’t climb into view until after midnight.
The head consists of five or six faint stars, depending on how it’s drawn. Most of them are so faint that they’re not visible from cities, or even the suburbs. Five of them share a name: Minazal. It comes from an Arabic phrase that means “belonging to the uninhabited spot” — an indication that they’re not much to look at.
The Minazals are numbered, based on their position in the head. The brightest is Minazal 1. It’s a binary — two stars locked in orbit around each other. The system is about 160 light-years away. Its main star is about three times the size and mass of the Sun, and dozens of times brighter. The companion is smaller and fainter.
The closest of the Minazals is number three, at 135 light-years. And the farthest is number 2, at almost 600 light-years. As seen from Earth, it’s the faintest member of the quintet. In reality, though, it’s the brightest — more than 2500 times brighter than the Sun — the most impressive star in the head of the water snake.