Messier objects from Taurus to Puppis
- Builds on
- Sections O1.2 and O1.8
- Reading time
- 45 min
- Exercises
- 3
- Olympiad problems
- 0
The Pleiades, M45, are the one Messier object that almost everyone has seen, a tight little group of six or seven stars that many people mistake at first glance for the Little Dipper. The winter sky round Orion holds 16 Messier objects in all. Most of them are open clusters, young stars still close together in the disc of our Galaxy, which is why they gather along the winter Milky Way, and they are among the easiest Messier objects to find. In this section we find each of them from the stars of Section O1.2.
O1.12.1Taurus and Orion
The Crab Nebula, M1, is the remains of a star that exploded in the year 1054. Near which star of Taurus does it lie?
The Pleiades lie 13.7° north-west of Aldebaran, and need no finding. The Crab Nebula, M1, a supernova remnant and the first object in Messier's list, lies 1.1° north-west of ζ Tau, the tip of the southern horn of the Bull. In Orion, the Orion Nebula, M42, is the hazy middle star of the sword below the belt, and the smaller De Mairan's Nebula, M43, is part of the same cloud, 0.14° north-east of the centre of M42. The faint reflection nebula M78 lies 2.5° north-east of Alnitak, the eastern star of the belt.
O1.12.2Auriga and Gemini
Three open clusters lie in a line across the southern half of Auriga, along the Milky Way. M36 lies 5.9° north of Elnath, the star shared by Auriga and Taurus. M38 is 2.3° north-west of M36, and M37, the richest of the three, 3.7° south-east of it. In Gemini, the large open cluster M35 lies 2.3° north-west of Propus (η Gem), at the feet of the western twin.
| Star | Tap a star on the chart. |
|---|---|
| Constellation | |
| Magnitude | |
| Angle between two stars | Tapping a second star gives the angle between them. |
| Hop | None drawn |
O1.12.3Canis Major, Monoceros, Puppis and Lepus
South-east of Orion, the open cluster M41 lies 4.0° south of Sirius, and is just visible to the naked eye under a dark sky. M50, in the faint constellation Monoceros, lies about a third of the way from Sirius to Procyon, 0.8° off the line between them. Due east of Sirius, at about 13°, lie the two open clusters M47 and M46 in Puppis, 1.3° apart. M47 is the brighter and looser of the two, and M46 is a rich cluster of fainter stars with a small planetary nebula, NGC 2438, in front of it. Further south in Puppis, M93 is 1.5° north-west of Azmidi (ξ Pup). The globular cluster M79, the only one of the winter sky, lies in Lepus 3.9° south of Nihal (β Lep). Last, the open cluster M48, in Hydra, lies 13.9° south-east of Procyon, in an empty part of the sky.
| Star | Tap a star on the chart. |
|---|---|
| Constellation | |
| Magnitude | |
| Angle between two stars | Tapping a second star gives the angle between them. |
| Hop | None drawn |
Sirius and Procyon are 25.7° apart. M50 lies about 0.36 of the way from Sirius to Procyon. How far is it from Sirius, along the line?
All 16 Messier objects of the section are listed below with their way from the nearest bright star.
| Object | From the nearest bright star |
|---|---|
| M45, PleiadesOpen cluster in Taurus, magnitude 1.2 | Around Alcyone (η Tau) |
| M1, Crab NebulaSupernova remnant in Taurus, magnitude 8.4 | 1.1° north-west of Tianguan (ζ Tau) |
| M42, Orion NebulaDiffuse nebula in Orion, magnitude 4.0 | 0.5° north of Hatysa (ι Ori) |
| M43, De Mairan's NebulaDiffuse nebula in Orion, magnitude 9.0 | 0.6° north of Hatysa (ι Ori) |
| M78Diffuse nebula in Orion, magnitude 8.0 | 2.5° north-east of Alnitak (ζ Ori) |
| M36Open cluster in Auriga, magnitude 6.0 | 5.7° south-west of Mahasim (θ Aur) |
| M38Open cluster in Auriga, magnitude 6.4 | 6.4° west of Mahasim (θ Aur) |
| M37Open cluster in Auriga, magnitude 5.6 | 4.9° south of Mahasim (θ Aur) |
| M35Open cluster in Gemini, magnitude 5.1 | 2.3° north-west of Propus (η Gem) |
| M41Open cluster in Canis Major, magnitude 4.5 | 4.0° south of Sirius (α CMa) |
| M50Open cluster in Monoceros, magnitude 5.9 | 9.4° north-east of Sirius (α CMa) |
| M47Open cluster in Puppis, magnitude 4.4 | 10.8° north of Azmidi (ξ Pup) |
| M46Open cluster in Puppis, magnitude 6.1 | 10.2° north of Azmidi (ξ Pup) |
| M93Open cluster in Puppis, magnitude 6.2 | 1.5° north-west of Azmidi (ξ Pup) |
| M79Globular cluster in Lepus, magnitude 8.2 | 3.9° south of Nihal (β Lep) |
| M48Open cluster in Hydra, magnitude 5.8 | 13.9° south-east of Procyon (α CMi) |
- The Pleiades are not the Little Dipper, though their shape is similar. The Little Dipper is far larger and holds Polaris, and the Pleiades fit easily inside one field of binoculars.
- M42 and M43 are parts of one cloud of gas, and M43 lies only 0.14° from the centre of M42. A question pointing at the Orion Nebula usually means M42.
- Of the three clusters in Auriga, M37 lies furthest to the south-east, and M38 furthest to the north-west, with M36 between them. Their numbers do not follow their order in the sky.
- O1.12.1
Which Messier object lies 4.0° south of Sirius?
The answer is (a). M41 lies 4.0° south of Sirius. M50 lies on the way to Procyon and M47 lies east of Sirius. - O1.12.2
How many of the 16 Messier objects of this section are globular clusters?
globular clusterOnly one of them, M79 in Lepus, is a globular cluster. The others are open clusters, nebulae and the Crab Nebula, which is a supernova remnant. - O1.12.3
A chart shows three open clusters in a line across the southern half of Auriga. Which is the middle one?
The answer is (b). M36 lies between M38, 2.3° to its north-west, and M37, 3.7° to its south-east.