The purpose of this list is to show that you do not always need a telescope to observe literally thousands of spectacular deep sky objects (DSOs) in the night sky. In most cases, the objects on this list can easily be viewed with a pair of 7×50 binoculars, provided the sky is reasonably dark, and the objects rise 25 degrees or so above the local horizon.
Note, however, that the images shown on this list were taken using imaging equipment attached to telescopes, and were selected solely to aid identification of the objects since some of their detail and structure may not be clearly visible through binoculars in less than perfect seeing conditions.
That said, if you have a pair of binoculars lying about the house, use them to observe some of these beautiful deep-sky objects tonight. You’ll be glad you did, and what’s more you’ll have saved yourself all the trouble associated with setting up a telescope. So without further a do, let us start our binocular tour.
NGC 129 – Open cluster
Right Ascension: 00h 30m 00s
Declination: +60° 13′ 06″
Apparent magnitude: 6.5
Distance: 5,450 light years
Discovered by William Herschel in 1788, this sparse but large cluster is located almost exactly mid-way between the stars Beta Cassiopeiae and Gamma Cassiopeiae in the constellation Cassiopeia. With binoculars, you will be able to see at least six stars with magnitudes ranging between 9 through 12, although it might be difficult to distinguish them from the background stars in the loose and scattered cluster, so look for the small triangle formed by three relatively bright stars in the centre of the cluster. In the image opposite, this triangle can be seen just below centre in the frame.
Alpha Persei Cluster – Open Star Cluster
Right Ascension: 03h 26.9m
Declination: +49° 07″
Apparent magnitude: 1.2
Distance: 557-650 light years
Also known as Melotte 20 or Collinder 39, this young cluster is just 50 million years old, and will show several blue stars when viewed without optical aid. However, with binoculars, the brightest star in the cluster, which is a white-yellow supergiant called Mirfak (Alpha Persei), becomes visible.
Other bright members of the cluster include Delta, Sigma, Psi, 29, 30, 34, and 48 Persei, with some stargazers referring to these stars as the “Attendants of Mirfak”. The stars in Melotte 20 share a common association and travel through space together.
Coma Star Cluster – Open Star Cluster
Constellation: Coma Berenices
Right Ascension: 12h 22.5m
Declination: +25° 51″
Apparent magnitude: +1.8
Distance: 280 light years
Also known as Melotte 111, this small cluster contains about 40 or so stars that share a common proper motion, which suggests a common origin. The stars in the cluster are all about 450 million years old, and stretch across about 7.5 degrees of the sky. In a high quality instrument, at least 90% of the cluster’s stars can be seen at the same time, so look for the distinctive “V” formed by the brightest stars as the constellation rises. Interestingly, Melotte 111 used to represent Leo’s tail until about 240 BC, when Ptolemy renamed it after Berenice, the legendary Egyptian queen who sacrificed her hair as an offering to the goddess Aphrodite for the safe return of her husband King Ptolemy III from the Third Syrian War (246–241 BC).
IC 4665 – Open Cluster
Right Ascension: 17h 46m 18s
Declination: +05° 43′ 00″
Apparent magnitude: 4.2
Distance: 1,400 light years
AS open clusters go, IC 4665 is among the youngest, being only about 40 million years or so old. Located about 1,400 light years away, this large open cluster stretches across 30 light-years of space, and consists of a few dozen stars of magnitudes 7 and 8.
It can be found to the northeast of Beta Ophiuchi, and is easily seen with binoculars from urban areas, but under dark skies, it is a naked eye object, and appears as a hazy spot covering a two Full Moons area of the sky.
Trumpler 2 – Open Cluster
Right Ascension: 02h 36m 00s
Declination: +55° 50′ 00″
Apparent magnitude: 5.9
Distance: 2,000 light years
Even though this cluster is located within the plane of the Milky Way (in the Perseus Arm), it has an apparent visual magnitude of 6, which means that under reasonably dark skies, it can be seen without optical aid, although binoculars provide a clearer view of the cluster’s more luminous stars. The brightest star in the cluster, HD 16068, is a K3-type giant star, is shown as the bright yellow spot just right of centre.
This open cluster is sometimes referred to as the Rabbit, as some of its stars are said to resemble a bunny with long ears, although binoculars of at least 80mm, and a magnification of x20 wil be needed to show the creature this asterism depicts. Around eight stars of magnitude 9.5 form most of the astrism, with a further four stars of magnitude 10 completing the shape.
NGC 2264 – Emission Nebula
Right Ascension: 6h 41m
Declination: +9° 53″
Apparent magnitude: 3.9
Distance: 2,600 light years
The designation NGC 2264 applies to two objects; the Cone Nebula at the bottom of the frame, and the Christmas Tree cluster, whose shining blue baubles lights up the nebulosity in the background like, well, a Christmas tree. Both objects are located about 2,600 light years away in the constellation Monoceros, and can be found near the feet of Gemini.
At magnitude 4.5, NGC 2264 can easily be seen with the naked eye under a dark sky, and makes a startling sight using binoculars. Two more objects, the Snowflake Cluster (best seen in infrared) and the Fox Fur Nebula, are sometimes associated with NGC 2264, although they are not officially recognized as being parts of NGC 2264
Melotte 25 (Hyades) – Open Star Cluster
Right Ascension: 4h 27m
Declination: +15° 52″
Apparent magnitude: 0.5
Distance: 153 light years
The Hyades cluster in the constellation Taurus is perhaps the best-known open cluster after the Pleiades (M45). Located only 153 light years away, it is one of the most intensely studied clusters since its several hundred constituent stars share a common origin, age, chemical composition, and proper motion across the sky. However, one of the brightest stars that form the distinctive “V” shape of the cluster, Aldebaran, is not a member of the cluster. At 65 light years distant, Aldebaran is much closer to Earth than the closest stars in the cluster, and merely happens to lie along the same line of sight as the cluster.
NGC 1981 – Open Cluster
Right Ascension: 05h 35m 12.00s
Declination: -04° 24′ 00.0″
Apparent magnitude: 4.6
Distance: 1,500 light years
The small cluster NGC1981 marks out the northernmost point of Orion’s sword, and consists of about 20 or so magnitude 6 and brighter stars that stretch across 25 or so minutes of arc.
Some observers report seeing the shape of a crocodile in the cluster, while others see a capital letter “F” tipped on its side. Still others see the shape of a running man in the background nebula designated NGC 1977, but regardless of what you see when you observe this striking assembly of bright stars, you will have to agree that it is an incredibly beautiful target for binocular observers.
NGC 253 – Spiral Galaxy
Right Ascension: 00h 47m 33s
Declination: -25° 17′ 18″
Apparent magnitude: 8.0
Distance: 11.4 million light years
Also known as the Silver Coin or Silver Dollar Galaxy, NGC 235 is a bright starburst galaxy whose energetic star formation activity in its nucleus causes it to glow brightly in the X-ray and gamma-ray wavelengths. It is also one of the largest galaxies known, with its high surface brightness making it one of the easiest galaxies to observe with binoculars and small telescopes, after the Andromeda Galaxy, (M31).
However, telescopes of 8-inch and larger apertures will reveal dust lanes and individual stars in NGC 253. NGC 253 was discovered by Caroline Herschel, the sister of William Herschel, in 1783.
NGC 2403 – Spiral Galaxy
Right Ascension: 07h 36m 51.4s
Declination: +65° 36′ 09″
Apparent magnitude: 8.9
Distance: 8 million light years
Located about 8 million light years away, NGC 2403 is an outlying member of the M81 Group of Galaxies, and bears more than a passing resemblance to M33, a satellite galaxy of M31. NGC 2403 contains about one billion stars, is about 50,000 light years in diameter, and contains large number of H II regions where stars are being formed at a relatively high rate. Although 10×50 binoculars will easily reveal this galaxy, observing the bridge of dust and gas that connects it to the star forming region designated NGC 2404, may require a small to medium telescope. Note the location of the supernovae designated SN2004DJ, which was observed in NGC 2403 in 2004.