Astronomers and Star Gazers need a challenge when observing. Novices can be easily overwhelmed by long lists of challenging objects. Expert observers can be so focused on their projects, they easily can ignore the challenge provided by observing with different instruments.
By presenting three objects in each of several different groups, the hope is to provide all observers, no matter what their experience level, no matter what type of instruments they have access to, challenging objects to observe. There is even a group for the one instrument we are all born with, the naked-eye. Astrophotographers and astroimagers are not ignored here, either.
No matter what your experience, no matter what you use to observe, get outside and “Keep looking up!”
February’s Sky Challenges
- Barnard’s Loop, also known as Sharpless 2-276, is an emission nebula in the constellation of Orion. It is part of a giant molecular cloud which also contains the bright Horsehead and Orion nebulae. The loop takes the form of a large semi-circular arc some 14° across. It is thought to have been created about 2.5 million years ago by a series of supernoavae that also gave rise to several runaway stars, including AE Aurigae, Mu Columbae and 53 Arietis. The stars within the Orion Nebula are believed to be responsible for ionizing the loop.You will need dark, cloudless, and transparent skies and may benefit from using a nebula filter to see this diffuse nebula.
- The Pleiades or M45. This well known open cluster lies in the constellation of Taurus. It is about 100′ across and contains about 100 stars. Why, you are wondering, is this easy to find object in the challenge list? Well, the six bright stars are fairly easy to see: Atlas, Alcyone, Maia, Taygeta, Electra, and Merope. The challenge here is to view Asterope, Caleano, Pleione, 18 Tauri, HIP 17776, and HIP17900.
- The third member of this month’s naked-eye challenges is to view the Andromeda Galaxy from inside of Loop 410 in San Antonio. A good place to try this would be at the February meeting of the San Antonio Astronomical Association at Christ Lutheran Church of Alamo Heights.
- M33 is a very large, very dim spiral galaxy in Triangulum. M33 is the third largest member of the Local Group of Galaxies. It is small compared to its big apparent neighbor, the Andromeda galaxy M31, and to our Milky Way galaxy, but by this more of average size for spiral galaxies in the universe. One of the small Local Group member galaxies, LGS 3, is possibly a satellite of M33, which itself may be a remote but gravitationally bound companion of the Andromeda galaxy M31. M33 is approaching the Milky Way at 24 km/sec.The Triangulum galaxy is of type Sc, and is a “late” representative of that type of galaxy so it is classified as an Scd. The pronounced arms exhibit numerous reddish HII regions, including NGC 604, as well as blueish clouds of young stars. Population II stars and globular clusters have been found. Although no supernovae have yet been detected in the Triangulum galaxy, several supernova remnants have, and were cartographed by radio astronomers with high acuracy. At least 112 variables have been discovered in M33, including 4 novae and about 25 Cepheids. A strong X-ray source is also situated in this galaxy.
- NGC 2354, an open cluster in Canis Major. It has an apparent diameter of 20′, it is round, and composed of relatively bright stars and a sprinkling of fainter stars. The center seems empty, with very few stars.
- The open cluster Collinder 70. It is about 150′ across and contains about 100 stars, including Orion’s Belt Stars. How many stars can you find?
Small Telescope Challenges
- For 2″ to 6″ telescopes:
- Observe the Sun. You will need a solar filter for this one. Please review Sky & Telescope‘s article on Viewing the Sun Safely before attempting to view the Sun. Never, ever look at the Sun without a solar filter!
- Winter Alberio (HD 56577), a binary star in Canis Major lying about 1.6° north of τ Canis Majoris and 0.5° west (2000.0 coordinates are: R.A. 7h 16m 36.8s, Dec. -23 deg. 18′ 56″). This colorful pair has an orangish primary and a blue-white secondary.
- Arp 336, also know as NGC 2685, an edge-on galaxy in Ursa Major, with an apparent size of 4.5′ by 2.4′.
Medium Telescope Challenges
- For 8″ to 14″ telescopes:
- The globular cluster, G1. G1 or Mayall II is located about 2.9 million light years away in the Andromeda Galaxy.
- Leo I, also known as the Regulus Galaxy. This dwarf spheroidal galaxy is a member of the Local Group of Galaxies and is a companion of the Milky Way. It is fairly bright at magnitude 9.8 and large, 9.8′ x 7.4′, but is only 12′ from Regulus making this a difficult object to view.
- Asteroid (26591) Robertreeves, formerly 2000 ET141
Large Telescope Challenges
- For 16″ and larger telescopes:
- Split Sirius
- NGC 2285/NGC 2288/NGC 2289 are three faint spiral galaxies in Gemini that lie within 7′ of each other.
- J 900 or PK 194+2.1 is a starlike planetary nebula that lies some 3° west-northwest of γ Geminorum.
- Novice: Star Trails
- Intermediate: IC2177 – Seagull Nebula
- Expert: B33/IC434 – The Horsehead Nebula