NGC 7822 in Cepheus – Old Men and the Sky

Cepheus is looking bad in the depiction Stellarium uses in their Western constellation art. The picture shows an old man sitting around in his bathrobe. It could be me in this pandemic if I had more hair. I would be offended if I were him. That depiction is way too close to the truth, too exposing, not nearly romantic enough. It is the women in his life making the big splash. He is just a geezer hanging out in lazy togs for everyone to see, reminding people innocently passing by, if they will listen, that he prefers to be called King. There you are old dad, taking up space in the sky, trying to think somehow you might be important. An old man’s lament.

NGC 7822 is by the king’s knee in the Stellarium constellation art.

Cepheus is the mythical king of Ethiopia and husband to the vain queen Cassiopeia. He figures as the weak father-figure in a royal family of constellations whose saga dominates the northern skies. Cepheus and Cassiopeia had a beautiful daughter named Andromeda. Both of these women in Cepheus’s life had things going on with the big wigs. Cassiopeia boasted that she and her daughter were more beautiful than the sea nymphs. The sea nymphs heard of the boast and did what sea nymphs do and got vociferously jealous. They complained to Poseidon, their trident wielding god of the sea. Poseidon, always with an ear and eye for the gals and presumably looking for distraction in an age before social media, agreed to punish Cassiopeia for her boastfulness by sending the sea monster Cetus to ravage the coast of Ethiopia. Good old-world entertainment. The monster was on its way to do its terrible work while Cepheus dithered, finding an oracle to ask how he could stop the devastation. Whatever could he do? The oracle, being the rascal oracles are–just look at today’s political pollsters–advised that the only way the gods could be appeased was the sacrifice of his gorgeous daughter. Andromeda was to be chained to the coastline for Cetus to devour. Cepheus was torn by the oracle’s false choice of protecting his beloved daughter and concern for the people of Ethiopia. In the end he caved and Andromeda, in her toga torn loose and her long flowing locks, was chained to a rock by the sea. Good thing for Andromeda that there were potent god-men about who were good with a sword and who thought there might be other ways to treat a woman and to deal with a monster. Perseus, mounted on his mighty winged war horse Pegasus, saw Andromeda and was smitten by her beauty. He swooped down, slew Cetus, and claimed the hand of Andromeda.

The ancient Greeks were not much impressed by Cepheus. They thought he acted beneath the royal authority and deportment expected of a ruler. Greek myth treats him as a weak character dominated by the desires of his compelling wife. The poet Aratus (3rd century BCE) sang of the king as “one that stretches out both his hands” no doubt in supplication to the gods, like the irascible Poseidon. Lindsey Graham in a bathrobe comes to mind.

Here Cepheus is with both hands stretched out, praising Perseus for fixing his mess. Pierre Mignard (1679) at Louvre Museum, Paris

Late October nights bring about a big change in astro-viewing and photography. The days are shorter and the starry nights longer and colder. In the U.S. West we have had weeks of severe clear without a cloud between here and Seattle to San Antonio. This year the last few days of October brought these clear skies of Indian summer and a full moon. Somehow, as astro-photographers all know, clear skies and a big moon often go hand in hand. I chose NGC 7822 to photograph because it was away from the moon and used a narrow band hydrogen-alpha filter to shoot through because the filter cuts out the light of the moon.

NGC 7822 in Cepheus, 10/28-30/2020. Click on photo to see acquisition details

Cepheus lends its name to the astronomically important Cepheid variable type star. I was glad to see old man Burnham, still the go-to observer guide, give proper credit to Henrietta Leavitt of Harvard for the discovery of Cepheid variables. He might have instead just credited her male boss Edward Pickering or his peer Harlow Sharpley. In 1912 Leavitt announced the results of her observations of variable stars in the Small Magellanic Cloud. By comparing photographic plates over time she had the insight that for certain variable stars their period of variability is related to their actual intrinsic luminosity. The longer the period, the brighter the star. This fact gave us a much better way of discovering how far away stars are. Consider a 100 watt light bulb. We know how bright it is intrinsically. The further it is away, the dimmer it appears. Knowing its intrinsic brightness we can measure its apparent brightness and calculate its distance from the viewer. Miss Leavitt’s stars gave us the same ability at the astronomical level. Edwin Hubble used this knowledge to realize that the blur known as M31 was two million light years away. This would make it a separate galaxy, now named after the happily rescued Andromeda, and all at once our galaxy was not the universe. Imagine the moment.

NGC 7822 is a star forming complex of glowing ionized hydrogen gas about 2900 light years away. King Cepheus might have been around about the time this light started its way to my telescope. The region is relatively young at a few million years old. One of the hottest stars known is a primary source illuminating the nebula. Its solar winds shapes the elephant trunk shaped pillars of creation you can see in my image if you look closely. As far as I can tell, that star is toward the top center of my image but is not one of the brighter appearing, closer stars. My image was taken over 3 nights of the last days of October where this old man grabbed 25 hours total of 10 minute exposures and used about 17 hours of the best of them here. I can’t say why, but here it is.

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