I recently heard a radio host mention the “dog days of summer” in reference to the hot and steamy weather we’ve been experiencing. His supposition was that the term was coined because dogs get hot and lazy during this weather. The term actually originated from ancient Greek and Romans and has nothing to do with our canine friends sprawled out, panting on the floor. Rather it relates to a star that is up in the sky.

Sirius is the brightest star visible from Earth. It’s so bright because it is twice as big as our sun and the fifth closest star to our planet at 8.6 lightyears away. The brightness inspired its name which comes from the Greek word for “scorching” or “glowing.” It is also called the “dog star” because it is in the constellation Canis Major (Great Dog).

In July and August Sirius is visible in the east just before sunrise. It travels across the sky with the sun all day. Greeks and Romans believed that the conjunction of these two bright heavenly bodies generated more heat, causing the hottest days of the year. The “dog days” are officially July 3 through August 11, a period which encompasses 20 days before and 20 days after Sirius and the sun rise and set together.

Since Sirius travels with the sun at this time of year, the constellation Canis Major is not visible now (look for it in the dark skies in December-March). However, the summer sky is full of other constellations that are worth looking for.

The Big Dipper, forming the shape of a ladle with a curved handle, is probably the easiest constellation to find. It is one of the most familiar constellations because it is visible all year in the northern hemisphere. Look to the northwest after sunset. In spring and summer, it is at its highest point, in the autumn and winter it dips closer to the horizon.

The Big Dipper is made up of seven bright stars. If the skies are dark enough and your eyesight is good enough (or you have a pair of binoculars) you may see an eighth star close to the second star from the end of the handle. This optical double star has been used as an eyesight test by numerous indigenous cultures.

The reason we can see the Big Dipper all year is because it rotates around the North Star, or Polaris and does not “set.” It can help you locate the North Star, not a particularly bright star, by drawing a line between the two stars at the end of the bowl of the dipper and continuing in the direction of the upper part of the ladle. The next visible star in that line will be Polaris. The North Star has been used for navigational purposes by mariners, enslaved Black people trying to escape the South, and birds during spring migration.

The Summer Triangle is another favorite star pattern. It’s huge, encompassing a large swath of the sky. Three prominent stars, Deneb, Altair and Vega create this isosceles triangle. Each of these stars are part of different constellations. Cygnus the Swan includes a distinctive cross-shaped pattern flying into the center of the triangle, with Deneb as the tail of the bird. Deneb comes from the Arabic word meaning tail. Altair makes up part of another bird constellation, Aquila the Eagle, which appears to fly opposite Cygnus the Swan. The bright star Vega (5th brightest star in the sky) is part of the constellation Lyra, the harp. The other stars that make up Lyra are much dimmer and are best viewed where skies are dark, away from light pollution.

Observers today may have difficulty discerning these constellation shapes and making sense of the ancient myths associated with them. Don’t let that keep you from going out on a clear, dark night, away from outdoor lighting, to gaze at the stars. If you are curious about constellations, star names and astronomical facts, visit the McAuliffe-Shepard Discovery Center in Concord. Or connect with the NH Astronomical Society. They offer free public observation stations around the state where they share their knowledge. Many libraries around the state have telescopes that can be checked out like a book.

Why not go out some evening? The heat of the dog days will be diminished after dark, and you’ll be treated to a free light show right above your head. Happy star gazing.