The Night Sky
January / February
Orion now dominates the winter sky to the south. As well as being home to both the Orion and Horsehead nebulae, Orion is a wonderful ‘guide post’ constellation, pointing the way to neighbouring constellation all winter.
A line through Orion’s belt leads to Sirius in Canis Major to the south-east; in the opposite direction it leads to Aldebaran in Taurus and on to the Pleiades. A line from Rigel through Betelgeuse leads to Castor and Pollux in Gemini.
Sirius is a brilliant white with a tinge of blue, but when the air is unsteady, or when it is low to the horizon it seems to flicker and splinter with all the colors of the rainbow. At a distance of just 8.7 light-years, Sirius is the fifth-nearest known star. Among the naked-eye stars, it is the nearest of all, with the sole exception of Alpha Centauri.
The Orion Nebula is easy to find and always wonderful to see in the telescope – the Horsehead Nebula is an extremely challenging visual target.
Double Stars in Orion:
Mintaka is easy to locate, as it is the westernmost of the three bright stars making up Orion's belt. It is actually a complex multiple system, but can be seen with a small telescope as a binary star with one star much brighter than the other.
Beta Orionis (Rigel) is a fine test for small-aperture scopes, because the companion hides in the glare of the main star.
Lambda Orionis is a delicate little pair, best seen with 75 – 90X.
Theta 1 Orionis The “Trapezium,” by far the finest multiple star in the night sky. Located in the brightest part of the Orion Nebula.
Iota Orionis is a fine double that sports the white and blue colors typical of many Orion doubles.
Struve 747 is another binocular pair. In telescopes, appears in the same low-power field as iota Orionis.
Theta 2 Orionis is a wide binocular pair located on the edge of the Orion Nebula.
Sigma Orionis is a nice, wide triple, best viewed using low power.
Struve 817 is a faint, but pretty pair is located just 1/3 degree south of Betelgeuse. A fine sight when captured in the same low-power field as this great star.
(You will probably need Stellarium to locate these stars).
Meanwhile, in the east, the constellation of Taurus (the Bull) has risen. The open cluster, M45, the Pleiades (often called the Seven Sisters), it is one of the brightest and closest open clusters and will richly repay a visit with binoculars. In a small telescope, the brightest stars can be seen surrounded by blue reflection nebulae caused by reflected light from many small carbon grains.
Also in Taurus is the Crab Nebula (M1 is the first entry of Charles Messier's catalogue). Lying 6500 light years from the Sun, it is the remains of a giant star that was seen to explode as a supernova in the year 1056. It may just be glimpsed with binoculars on a very clear dark night and a telescope will show it as a misty blur of light.
In 2017, the first major shower of the year, the Quadrantids, will peak on the night of January 4th and early morning hours of January 5th. The next meteor shower (Lyrids) is not until April.
At the feet of the Twins lies Messier 35. Located just off the trailing foot of Castor, M35 can barely be seen with the unaided eye on dark transparent nights. In low-power binoculars it may look like a dim, fairly large unresolved interstellar cloud. Even through light-polluted suburban skies, 7x glasses reveal at least a half dozen of the cluster's brightest stars against the whitish glow of about 200 fainter ones. M35 has been described as a "splendid specimen" whose stars appear in curving rows, reminding one of the bursting of a skyrocket.
In Cancer, appearing to the eye as merely a misty patch of light, binoculars will quickly reveal M44 as a beautiful open star cluster, containing hundreds of tiny stars. It is known to some as "Praesepe”, the Manger. The cluster also goes by the name "Beehive," a moniker that apparently evolved almost four centuries ago, when some anonymous person, upon seeing so many stars revealed in one of the first crude telescopes exclaimed: "It looks just like a swarm of bees!"
The Double Cluster of Perseus
NGC 869 and 884 are magnificent through binoculars or the low-power field of a small telescope; a pair of glorious open clusters, each of which would be beautiful by itself. The overall diameter of each cluster is about 45 arc minutes, or about one-third larger than the apparent diameter of the moon. So you should use very low powers to get both clusters together in the same field of view. Close inspection with a telescope will reveal a fine ruby-colored star near the center of 884.