Taurus, the Bull, is a distinctive constellation that lies just northwest of Orion, high in the evening sky in late winter. A V-shaped group of stars forms the bull’s head, and two long horns extend to the northeast. Taurus’ brightest star, Aldebaran, marks one of the bull’s eyes.
Several large open star clusters lie within the borders of Taurus. The largest of these clusters, called the Hyades, lies at the head of Taurus. Except for Aldebaran, all the stars that outline Taurus’ head are members of the Hyades cluster. The cluster also contains a number of fainter stars that are visible with binoculars. The wide field-of-view provided by binoculars makes them the best instruments for viewing the Hyades cluster. This cluster appears so large because it is one of the nearest open star clusters, at about 150 light-years from Earth.
The Pleiades cluster, which lies just over 10° northwest of Taurus’ head, is the best-known star cluster in Taurus. At 1° across, the Pleiades cluster is much more compact and cluster-like than the Hyades cluster. The brightest stars of the Pleiades cluster form a dipper-like shape; people sometimes confuse the cluster with the Little Dipper, which is a constellation many times larger than the Pleiades. The Pleiades cluster is also called the Seven Sisters, but there are far more than seven stars in this cluster. If you have good eyesight and a dark sky, you may be able to see nine or more stars in the Pleiades without any optical aid.
Binoculars and telescopes both give excellent views of the Pleiades. Binoculars provide enough magnification and gather enough light to show many of the cluster’s fainter stars while still showing the cluster in the context of the surrounding star field. Even at the lowest possible magnifications, most telescopes magnify the Pleiades enough that it loses its “cluster” appearance. However, careful observation with a telescope under dark skies may reveal the reflection nebula that enshrouds the stars of the Pleiades. This nebula is easiest to see near Merope, the bright star at the bottom left corner of the “dipper bowl.” Clean optics will be helpful for spotting this nebula because it can easily hide in any glare around the bright stars of the cluster.
Of course, not every star cluster appears as large and bright as the Hyades and Pleiades. In addition to these two clusters, Taurus contains several nice star clusters of more ordinary dimensions. Two such clusters, NGC 1647 and NGC 1746, both lie almost perfectly along a line between Aldebaran and Alnath, the star marking Taurus’ right horn. NGC 1647 lies only about 3.5° from Aldebaran, while NGC 1746 lies about two-thirds of the way from Aldebaran to Alnath. Both clusters require fairly low magnification, and they are both easily visible with binoculars as small fuzzy patches with a few stars resolved.
The most prominent nebula in Taurus is M1, the Crab Nebula. The Crab lies about 1° northwest of Zeta Tau, the star marking Taurus’ left horn. This nebula is the expanding cloud of gas that was left behind when a star exploded in A.D. 1054. Chinese astronomers recorded that the supernova which created the nebula was visible during the day for three weeks.
The Crab Nebula is bright enough to be visible with binoculars as a tiny fuzzy oval. Observing the nebula with binoculars can be a little challenging, but it will be much easier if you have a stable support and a dark sky. The Crab Nebula is easy to see in almost any telescope as a fuzzy gray oval. The brightest area of the nebula makes a fat S shape in the oval of the nebula. Even with large telescopes, it is difficult to observe details beyond the nebula’s basic shape. However, carefully observing the Crab at high magnification, especially with an OIII filter, may reveal traces of filamentary structure around the edge of the nebula.
