The best deep-sky targets in Taurus

The constellation Taurus the Bull is an easy one to find in the Northern Hemisphere’s fall and winter skies. It stands opposite the Sun at the beginning of December.

The head of the figure is a large V of stars, and standing out among them is the ruddy 1st-magnitude star Aldebaran (Alpha [α] Tauri) marking one of its eyes. This star, along with Antares in Scorpius, Fomalhaut in Piscis Austrinus, and Regulus in Leo, were the four Royal Stars of ancient Persia.

If you’re new to constellation identification, the best way to locate Taurus is to wait until the easily recognized constellation Orion the Hunter rises into view. Then, using the three stars that mark Orion’s belt, draw a line upward, and you’ll arrive at Aldebaran.

A bit of stellar trivia involves the star Elnath (Beta [β] Tauri). On many star charts dated before 1928, it was a shared star with Auriga, being designated as both Beta Tauri and Gamma (γ) Aurigae. Once the International Astronomical Union formalized the constellation boundaries, however, Elnath was made part of Taurus, probably because the letter Beta comes before Gamma in the Greek alphabet.

Taurus also is the location of an important discovery made by Italian astronomer Giuseppe Piazzi on Jan. 1, 1801, when he found Ceres roughly 3° north of the 4th-magnitude star 5 Tauri. It was the first asteroid to be discovered.

As to our observing list, the objects are in order of right ascension, from west to east. So, if you start with the first object high in the sky, the others will rise in order after it, giving you more observing time when they’re best seen.

Starting off with a bang, our first target is the Pleiades (M45), and it couldn’t be easier to find. Just extend the line from Orion’s Belt that you used to find the V of Taurus and it will lead you to this magnificent open cluster.

At magnitude 1.6, M45 is tied for seventh place in brightness among all deep-sky objects. It’s also deceptively huge. With a diameter of 1.8°, it covers as much area as 12½ Full Moons.

We don’t know why French comet hunter Charles Messier chose to include it in his now famous catalog of nebulous objects that aren’t comets. Even thousands of years before he lived, skywatchers knew it wasn’t a comet. In fact, the Greek astronomer Eudoxus, who lived in the 4th century b.c.e., referred to the group as the Clusterers, and considered it a constellation.

One of the most popular names for M45 is the Seven Sisters. This implies that there are seven visible stars in this group, but human eyesight varies a lot. The majority of people can only see six stars, but if you have great eyes and are at a dark site on a night of good seeing (atmospheric steadiness), you may be able to identify 10 or more Pleiades.

Probably the best way to observe this cluster is to use binoculars. Any will give good views, but the finest come from high-quality 7×50, 10×50, and 11×80 instruments.

If your observing site is dark, try to see the Merope Nebula (NGC 1435). This reflection nebula surrounds (in an irregular way) the star Merope (23 Tauri). I’ve seen it through a 4-inch scope using a magnification of 30x, but it was tough. A larger aperture will certainly help, but keep the power low.

Next on our list is a planetary nebula called the Crystal Ball Nebula (NGC 1514). It glows softly at magnitude 10.2 and has a diameter of 114″. To find it, look roughly 3½° east-southeast of Atik (Zeta [ζ] Persei).

To properly view NGC 1514, use at least an 8-inch telescope. That’s because you also should use an Oxygen-III filter to dim the nebula’s 9th-magnitude central star, and that filter doesn’t let much light through it.

Although an 8-inch will give a satisfying view, if you can step up to a 16-inch or larger scope, the Crystal Ball will explode with detail. Rather than simply a round haze, you’ll see an irregular central section with a few dark zones, surrounded by a faint outer ring.

Our next target is the double star Chi (χ) Tauri. It’s not too bright, so if you can’t find it from the chart, look roughly midway between brighter Elnath and the Pleiades, slightly closer to the latter.

This is a pretty binary that some observers call winter’s Albireo (Beta Cygni), but not as bright. The two stars in Chi glow at magnitudes 5.5 and 7.6. The brighter one (always called the primary in double-star speak) appears yellow to most people, and the fainter one (the secondary) looks blue. Of course, because color perception in human eyes varies, your view may be different.

The two stars are separated by 19.4″, so any size telescope with a medium-power eyepiece will show both components easily.

Now we come to an object that you’ll need at least a 14-inch telescope to spot. It’s Hind’s Variable Nebula (NGC 1555), named in honor of its discoverer, British astronomer John Russell Hind, who found it in 1852.

NGC 1555 is a reflection nebula that we see because of its location near T Tauri. There’s a problem, though. T Tau is a variable star. Usually, its magnitude hovers around 10, but it can dip to 14 and stay there for a year or more. This is why it’s called Hind’s Variable Nebula. When T Tau is at minimum brightness, you have no hope of spotting the nebula.

Finding Hind’s Variable Nebula is a two-step process. First, look 1.7° west-northwest of Epsilon (ε) Tauri and locate SAO 93887, which glows at magnitude 8.4. Second, nudge your scope 5′ to the northeast of that star, and you’ll find T Tau. Next to it (if your scope is big enough and your night clear enough), you’ll hopefully see an unevenly lit wedge of light. That’s NGC 1555.

Our next target is the Hyades, whose luminaries are Alpha, Beta1, Beta2, Gamma, Delta (δ), and Epsilon Tauri. On other lists, it goes by Melotte 25, Collinder 50, and Caldwell 41. This object is an open cluster. Well, most of it, anyway; Aldebaran isn’t part of the cluster. That bright star lies 65 light-years from Earth, while the other stars are 150 light-years away. But Aldebaran is lumped in, giving the Hyades the impressive magnitude of 0.5. It’s also quite large, having a diameter of 5½°.

Because of its large size, don’t use a telescope to observe it unless you’re looking to split some of its double stars. You’ll get your best views through binoculars.

Now turn your gaze to the Pirate Moon Cluster (NGC 1647), which glows at magnitude 6.4 and measures 45′ across. To find it, point your scope 3½° northeast of Aldebaran. If the seeing at your site — and your eyes — are good enough, you might be able to spot a fuzzy patch without optical aid. The best way to observe NGC 1647 is through an 8-inch or larger telescope. If you start with the eyepiece that gives you the lowest magnification, the cluster should be nicely framed within the field of view. Then spend some more time with it as you crank up the power and split half a dozen or more double stars.

Next on the list is the reflection nebula IC 2087, which you’ll find 3.9° east of Chi Tauri. An 11-inch scope shows it as a not-quite-round haze 4′ across. Note the abundance of dark nebulosity in this area. Part of it hides the star whose light IC 2087 is reflecting in our direction.

Now it’s time to encounter open cluster NGC 1746. At least, that’s how it was designated shortly after it was discovered in the middle of the 19th century. Further study has revealed that NGC 1746 is actually a pair of clusters, one in front of the other. The closer one, NGC 1750, lies roughly 2,000 light-years away, while the farther one, NGC 1758, is 2,500 light-years distant. Because the two clusters aren’t physically related, NGC 1746 is now classified on most lists as an asterism. You’ll find it a bit more than 2° north of Iota (ι) Tauri.

When you observe NGC 1746, you can pretty much tell which stars are in which cluster, mainly because all the stars in each region have the same brightness. So, the (apparently) brighter dozen or more belong to NGC 1750, and the fainter field stars are in NGC 1758.

Our next two targets, a pair of open clusters less than ½° apart, lie quite close to Taurus’ boundary with Orion. To find the first, NGC 1807, move not quite 2° northeast of 11 Orionis, the topmost star in the Hunter’s shield. It glows at 7th magnitude and measures 5.4′ across.

The second of the pair, NGC 1817, stands 0.4° east-northeast of NGC 1807. At magnitude 7.7, it’s a bit fainter, but nearly three times as large, having a diameter of 16′. Most observers think it’s a prettier cluster than its brighter counterpart, but there’s something to be said for each.

A small scope at medium power will show about 30 stars in NGC 1817, and as you increase the aperture, you’ll see more and more. NGC 1807, on the other hand, shows about two dozen stars through any size scope. The main six form a jagged line, oriented north-south.

The second double star on our list is 118 Tauri, which is 3½° south of Elnath (Beta Tauri). It’s not as colorful as Chi Tauri, but seeing different colors in the two components is a fun challenge.

The primary star glows at magnitude 5.8 and is bluish-white. The secondary, at magnitude 6.6, displays a blue hue. Can you see a difference? With a separation of 4.8″, splitting the two stars is easy through any scope.

The final target on our list is the first entry in Messier’s list — M1. It’s also known as NGC 1952, but most observers call it the Crab Nebula. To find it, look 1° northwest of Zeta Tauri.

M1 is a supernova remnant, an expanding shell of gas formed when a supergiant star exploded. It was first seen by Chinese astronomers in 1054, and it could be seen for a year before fading away. What amateur scopes reveal now is a whitish rectangular cloud that measures 6′ by 4′ and glows at magnitude 8.4.

Because of its high surface brightness, the Crab takes high magnification well. So, crank up the power until the image starts to break down because of sky conditions, and look for its irregular border and darker areas across its face.

I think that as you grab the Bull by its horns (or its deep-sky objects), you’ll have a great time with the cool objects in this constellation. Good luck!