February 2024
The Backyard Astronomer
Adam England

Unicorns and Roses

A less well known and relatively modern constellation fills the void between Orion, Canis Major, Hydra and Gemini, though with modern light pollution the stars are difficult to see with the naked eye. Monoceros – mono meaning “one” and ceros meaning “horn” – the Unicorn is a simple seven-point constellation, but only two of the stars are usually discernible without binoculars or a telescope. Coined by Dutch cartographer Petrus Plancius in the 17th century, Monoceros contains many intriguing objects for the amateur observer.

The nose of the unicorn is quite easy to locate. Start with the bright orange shoulder of Orion, the easily identifiable star Betelgeuse, and the dimmer blue star Meissa that marks the Hunter’s head. Draw a line from Meissa to Betelgeuse, continuing nearly that same distance again to the Southeast of Betelgeuse to find the binary system ε Monocerotis, denoting the nose of the unicorn. Just a slight look continuing to the east will place the Rosette Nebula in your view.

Rosette Nebula (NGC 2237)

About 5,200 light-years distant, the Rosette Nebula takes its name from the stylized floral design, often seen as a textile rose awarded for competitions. In 1690 English astronomer John Flamsteed first noted the nebula, its circular shape and dark center, reminiscent of a rose. Approximately 130 light-years across, this emission nebula is a star nursery, estimated at more than 10,000 solar masses. The intense radiation of the juvenile stars in this densely packed space excites the molecules in the clouds of gas and dust around them, emitting more and more radiation in a chain of events that continuously sends ever increasing quantities of ultraviolet and X-ray radiation in all directions. For us this equates to a beautiful nebula, perfect for our viewing pleasure. At an apparent magnitude of 9.0, even small telescopes can resolve this stellar breeding ground.

Enjoy the Rosette Nebula, Monoceros and Orion in the southern sky in the early evening hours through February. Wishing you clear skies!

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.