The Red Planet shines bright this month, transiting between the horns of Taurus the Bull and up toward Gemini the Twins, at just over one astronomical unit from Earth. One AU is the average distance from the Earth to the Sun, or about 150 million kilometers (93 million miles).
The peaks of the horns of Taurus are the bright stars Zeta Tauri and Elnath. At apparent magnitudes of 3.0 and 1.67, respectively, they are relatively easy to find by looking to the southwest after sunset. Zeta Tauri is a binary system, with the brighter Zeta Tauri A eleven times more massive than our sun and separated from its partner Zeta Tauri B by only 1.17 AU, nearly as close to each other as we are to the Sun or Mars right now, so we cannot see them as separate objects with backyard telescopes. Scientists have been able to measure their Doppler shift — the change in the frequency of their light spectra — to calculate an orbital period of just 133 days.
About one degree west of Zeta Tauri is the popular and magnificent Crab Nebula. You can approximate one degree in the sky using the width of your finger at arm’s length. The Crab Nebula bears the designation Messier 1 (M1) because it was the first object recorded by Charles Messier in 1758 during his research to locate the predicted return of a comet, as previously calculated by its namesake, Edmund Halley. This same nebula was independently discovered by multiple astronomers during the 18th century, and has since become one of the most studied and beloved objects in the night sky. Modern observations using the Hubble Space Telescope, the Chandra X-Ray Observatory and the Spitzer Infrared Telescope have continued to provide extraordinary detail of this magnitude-8.4 remnant of an ancient supernova, which was recorded by Chinese astronomers in 1054.
Defining the bull’s other horn is Elnath (from the Arabic for “butting one”). Relatively close at 130 light-years distant, this giant star is five times the mass of our sun and puts out about 700 times more light.
While the Pleiades is the most familiar open cluster in the constellation Taurus, it hosts many other star clusters and nebulae. The Hyades cluster is nearer the bright star Aldebaran in the face of the bull, with about 100 stars of similar age and chemical composition filling a spherical area of space.
Moving counterclockwise from the west around Elnath, you can find the Flaming Star Nebula (magnitude 6.0), M38 or the Starfish Cluster (magnitude 7.4), and M36, the Pinwheel Cluster (magnitude 6.3).
If you would like to learn more about the sky, telescopes, or socialize with other amateur astronomers, visit us at prescottastronomyclub.org or Facebook @PrescottAstronomyClub to find the next star party, Star Talk, or event.
Adam England is the owner of Manzanita Financial and moonlights as an amateur astronomer, writer, and interplanetary conquest consultant. Follow his rants and exploits on Twitter @AZSalesman or at Facebook.com/insuredbyadam.