I wanted to tell you about the tiny constellation Delphinus the Dolphin and I’m happy to finally get there.
Less than a hundred years ago, the International Astronomical Union officially divided the sky into eighty-eight constellations to standardize the night sky around the world. Forty-eight of these constellations were cataloged by the Greek astronomer Ptolemy in the second century. Since then, the other 40 have gradually been added, many of them in the southern hemisphere.
Delphinus the Dolphin is one of Ptolemy’s original constellations. Although it is small and dark, it is very distinct. It is one of the few constellations that really looks like it is supposed to. Even though it is the 19th smallest constellation, it is one of my favorites. Once you see it, you will never forget it. Delphinus is made up of a skinny little diamond of faint stars that outlines the torso and head of the little dolphin and a single faint star that marks the tail. Delphinus swims in the celestial sea of the western sky on those first evenings after dusk.
Even though the five main stars that make up the delicate Delphinus seem dim to us, nothing could be further from the truth. Each of these stars is much larger and more powerful than our sun, and they emit much more light and energy than our parent star. Their weakness in our night sky is simply due to their great distance from us. They range from 95 light years to over 360 light years.
Throughout the ages, people have used constellations to tell stories related to religion or local mythology. This is certainly the case with Delphinus. Many early Hebrew cities saw Delphinus as a whale, reminding them of the Old Testament story of Jonah and the whale. The early Christian colonies considered the small diamond of stars to be the cross of Jesus.
I love Greek mythology tales about Delphinus. This is Poseidon, the god of the sea. As with most Greek gods, Poseidon was a real playboy who moved around in his youth. After many years, he tried to domesticate and marry. He set his sights on Amphitrite, one of the many Nereids who occupied his domain. According to legend, the Nereids, or Sea Nymphs, were like mermaids and their mission was to provide safety and protection to sailors and fishermen.
Despite Poseidon’s attempted charm and all his seductions, Amphitrite was disappointed and avoided him like the plague. She hated the god of the sea. Poseidon wasn’t about to give up on his ill-fated pursuit. He was determined to get his prize, so he kidnapped Amphitrite and put her in a cage. How about this for charm and class?
One day, when one of Poseidon’s guards opened the cage door, she yelled at him at the top of her voice. It was so sharp that it stunned the guard just long enough for her to slip up behind him, swimming her tail as fast and as far as she could.
Even after Amphitrite’s Great Escape, Poseidon didn’t give up. He swore to change his ways and become a nice guy. He sent Delphinus, his faithful and magical dolphin, in search of Amphitrite. Not only could Delphinus speak, but he was also a diplomat. He managed to find Amphitrite and persuaded her to give Poseidon another chance. She finally agreed, rode on the back of Delphinus and returned to the god of the sea. They were happily married, and as a reward Poseidon placed his faithful dolphin in the heavens like the constellation we still see from thousands of years later.
It might take a little work to find the little dolphin in the sky, but it’s totally worth it.
Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis/St. Paul and is the author of the book “Stars, a Month by Month Tour of the Constellations” published by Adventure Publications. Send your questions to
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