2011 Observer Challenge List

Below is the 2011 Observer's Challenge Objects list.

NGC 281 by LVAS President, Jim Gianoulakis

NGC-281 is an H-II region of nebulosity that also contains sparse open cluster IC-1590 and the asterism Barnard 1.  The object gets its name from the curved shape that resembles the Pac-Man character.  It lies in the constellation of Cassiopeia and sits just below the right V of the W.  The Pac-Man Nebula was discovered in 1883 by E.E. Barnard.  The multiple star, or asterism, also called HD 5005, is known as Barnard 1 and consists of a mag. 8 primary star along with four dimmer companions.

With larger backyard telescopes, the glow of the nebula is fairly easy to spot by sweeping the area.  However, to see detail, it is best viewed with an O-III filter.  A smaller scope (and even some finders) may show a faint glow with or without a filter.  Some of that glow may be from the cluster or the asterism.

The more severe challenge is seeing a fourth star in Barnard 1.  Many have resolved three stars but there is a fourth that only a few have seen.  In photographs of the nebula, a bright star within the cluster area of the nebula looks a bit fat.  That fat star is the asterism.  Using higher magnification of at least 150X, it can be recognized as a triple star.  However, with superb optics and excellent viewing conditions, there is a fourth star within that group.  As for the fifth companion, it may well be beyond the range of most backyard telescopes.

NGC 7380, The Wizard Nebula

Image by Hunter Wilson - in Hubble Palette Ha/OIII/SII with amateur equipment

NGC-7380 is an open cluster in a star-rich area of Cepheus.  Discovered by Caroline Herschel in 1787, she failed to note the nebulosity at the time.  Later, when the nebulosity was discovered, it was given the designation Sharpless or Sh2-142.  It is commonly known as the Wizard Nebula, a name derived more from photographic images rather than visually.  Many confuse the nebula with the cluster and mistakenly list NGC-7380 as the Wizard Nebula when in fact it is merely the rather obscure cluster.  At mag. 7.2, it is a loose collection of maybe 125 stars total, but good luck picking out which ones are actually part of the cluster!  The magnitudes of the actual members vary widely.  For most observers with backyard telescopes, the nebula will be invisible without a filter so be sure to have an O-III handy if one is available.  If not, a UHC or LPR may help if the skies are dark.  The challenge still counts if one sees either the cluster, the nebula or both.

NGC-6946, also known as ARP 29 or Caldwell 12, is known as the Fireworks Galaxy.  It is a face-on spiral galaxy and lies approximately 22 million light years away.  William Herschel discovered it in September, 1798.  Nine supernovae have been discovered within the galaxy.  It is highly obscured from us by interstellar dust.  It shines at mag. 9.6.

It is fairly easy to locate on the border between Cepheus and Cygnus.  Through smaller scopes it appears as a round smudge, but through larger optics, maybe 10-inches or more, the spiral structure may be visible, depending on sky conditions and the observer’s eye.  What is particularly interesting about this object is that if one were using a wide-field eyepiece, there is a nice open cluster nearby; NGC-6939 can be squeezed into the field of view.  If the scope is large enough, the view of the spiral structure of the galaxy and the sprinkling of the open cluster provides a spectacular view.  An added bonus, if the optics are big enough, is the small and obscure UGC-11583, a mag. 14.3 galaxy that appears as a faint oval smudge.  For most challenge members, this small galaxy is beyond reach.

The main challenge is, of course, the galaxy itself.  The faint round glow may or may not reveal spiral structure, depending on aperture, sky conditions, and one’s eyes.  However, within that glow, one might be able to detect the twinkling of several faint stars superimposed upon that glow, giving the galaxy its nickname.