The now defunct constellation of Poniatowski’s Bull still can be spotted high in the southern sky at about 10 p.m., not far from the bright stars Altair and Vega and on the western edge of the Milky Way’s Great Rift.

Jimmy Westlake/Courtesy

The now defunct constellation of Poniatowski’s Bull still can be spotted high in the southern sky at about 10 p.m., not far from the bright stars Altair and Vega and on the western edge of the Milky Way’s Great Rift.

Jimmy Westlake: Poniatowski’s Bull

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Jimmy Westlake

Jimmy Westlake's Celestial News column appears Tuesdays in the Steamboat Today.

Find more columns by Westlake here.

— There was a time when you could go outside and invent your own constellation. If it caught on with enough people, you could achieve a sort of immortality in the stars.

While there is no law prohibiting you from connecting the stars into whatever pattern you fancy, our modern day constellations are more or less written in stone out of a matter of scientific convenience. You see, by the 1920s there literally were hundreds of star patterns that filled the sky, and different folks in different parts of the world imagined different pictures in the stars. It became so difficult for astronomers to communicate with one another about the constellations that they decided it was time to determine once and for all which of the hundreds of constellations would become permanent fixtures in our night sky and be officially recognized all across the world. When the smoke cleared, 88 constellations remained, including the 48 original Greek constellations and 40 more recent additions. Dozens of others were cast into the trash heap of history to be forgotten.

One such discarded constellation, Poniatowski’s Bull, shines down in our late summer sky. Polish astronomer Marcin Poczobutt invented this star pattern in 1777 to honor his king, Stanislaus Poniatowski, who ruled Poland between 1764 and 1795. It was never a bad idea to flatter your king, especially if you needed funds for something like a new telescope for the royal observatory. Poczobutt confiscated a few stars from the classical summer constellations of Ophiuchus and Aquila to create his new constellation. The distinctive V-shaped group of stars that forms the face of this summertime bull bears a striking resemblance to the more familiar face of our wintertime bull, Taurus. It’s easy to spot, not far from the bright Summer Triangle star Altair and on the western side of the Great Rift in the summer Milky Way.

The stars of Poniatowski’s Bull were once thought to form an actual star cluster, such as the famous Seven Sisters, or Pleiades, but it turns out to be a chance alignment of unrelated stars, more like the famous little Coathanger asterism. Sweeping this area with binoculars, though, will reveal several other sparkling star clusters nearby.

Just off of the right tip of the “V” of Poniatowski’s Bull is one of the most remarkable stars in the whole sky, a faint little red dwarf named Barnard’s Star for its discoverer, famed American astronomer E. E. Barnard. Shining from six light years away, Barnard’s Star is the second closest star to our solar system, after the Alpha Centauri system, and is such a low wattage bulb that it is not visible to the naked eye or even in binoculars. What makes Barnard’s Star unique is its rapid proper motion across the heavens relative to the surrounding stars. It moves about 10 seconds of arc per year across our line of sight, which adds up to about one-half the apparent diameter of the full moon in a human lifetime. Had the ancient Greeks been able to see this faint star, they would have seen it a whopping 7 degrees from where we see it today. Barnard’s Star has the greatest proper motion of any known star.

Alas, Poniatowski’s Bull now been has re-annexed into Ophiuchus, the Serpent Bearer, but it is not forgotten.

Jimmy Westlake teaches astronomy and physics at Colorado Mountain College’s Alpine Campus. He is an avid astronomer whose photographs and articles have been published all across the world. Check out Jimmy’s astrophotography website at www.jwestlake.com.

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