Delphinus: Find the Starry Summer Dolphin

Swinging high overhead on summer nights, a tiny starry dolphin swims through the night sky. Find Delphinus tonight!

Delphinus as depicted in Urania's Mirror, a boxed set of constellation images by Sidney Hall. Image Source

The first step to finding the dolphin constellation is to find the Summer Triangle, a trio of bright stars visible all summer and well into the fall. After the Sun sets, look toward the East. Near the zenith of the sky, you will see the blue-white star Vega shining brightly. If you take a little more time to look, I bet you will be able to find two other bright stars that, with Vega, form a large triangle. See star chart below, set for Peoria at 10 PM. 

The Summer Triangle is easily visible this time of year. Image source: Stellarium and me.

 Click here to read more about the Summer Triangle and its constellations. 

Now that you have located the Summer Triangle, look below and a bit to the left of Altair,  the bottom star in the triangle. There is a compact group of stars that really does look like a dolphin (with a bit of imagination). 

Click on image to enlarge. Can you see the small dolphin shape below and left of Altair?

Here is the same scene, with constellation lines and images to help your imagination. 

Constellation lines show Delphinus as a lopsided box with a tail.

A little imagination can help you find the dolphin shape!

The stars in Delphinus are not as bright as the three stars that mark the Summer Triangle, so it will be harder to spot in a light polluted city. If you get out of the city to a darker sky, it will be easily visible with the unaided eye.

Constellations have long been used to help remember star patterns - ancient Greek sailors used constellations for navigation, and farmers watched the changing star patterns to predict the seasons. Since dolphins were a familiar sight to ancient mariners, it is no surprise there is a dolphin constellation. 

François Boucher, Arion on the Dolphin, 1748. In this oil painting, the mythical dolphin has been transformed into a sea monster. Image Source

One myth associated with the constellation tells the story of how a dolphin saved the life of the poet Arion (a real person who lived in the 7th century BCE). According to the legend, Arion's reputation as a skilled musician and poet made him quite popular throughout Greece and somewhat wealthy. While returning to Greece by ship from a tour of Italy, sailors plotted to kill him and steal his fortune. 

The sailors surrounded him with drawn swords. Arion begged to sing one last song in praise of the god Apollo. His beautiful music attracted a school of dolphins who swam along the ship. Placing his faith in the gods, Arion leapt overboard, and one of the dolphins carried him on its back to Greece. Apollo, god of music and poetry, placed the dolphin in among the constellations. Close by is the constellation Lyra in the Summer Triangle, which represents Arion's lyre. The myth of Arion and the dolphin has been the subject of many paintings, such as the example above, as well as several operas.

So next time you are out on a clear night, look up! I bet you will be able to find the Summer Triangle. And if your sky is dark enough, look for the little starry dolphin. Remember, you can always learn what's happening in the sky and get the latest news from space at the Dome Planetarium at the Peoria Riverfront Museum. Follow us on Facebook and Twitter for daily updates!  

Join us for a space party this weekend! Cocktails, science demos, exhibit, planetarium show, oh my!