Tony Flanders' Astronomy Site
Messier Guide: Late Autumn
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The dominant object of late autumn is M31, the Andromeda Galaxy, by far the biggest, brightest, and most prominent galaxy visible from locations north of the tropics. If you can tear your eyes from M31 and its companions M32 and M110, the octile of the sky from RA 0 to RA 3 also contains a smorgasbord of other interesting objects: two of the galaxies that are hardest to see under heavy light pollution (M33 and M74), the nearest galaxy with an active nucleus (M77), the faintest of the Messier objects (M76), and a very bright albeit sparse open cluster (M34). Here is the complete list of objects for this section, all of the Messier objects from RA 0 to RA 3 minus M103, which was covered in the previous section:
Obj S178S70U178U70 TypeConRADec MagPBrtSBrtSize
M110 3C3C4C5C GALAnd00:40.4+41:41 8.119.822.722x11
M32 2C3C2C3C GALAnd00:42.7+40:52 8.117.721.18.7x6.5
M31 1A1B2B2C GALAnd00:42.7+41:16 3.416.622.2191x62
M33 3A3B4C4C GALTri01:33.9+30:39 5.720.123.071x42
M74 4D5D5D-- GALPsc01:36.7+15:47 9.420.523.111x9.6
M76 2B4C3B-- PLNPer01:42.4+51:34 10.118.620.42.7x1.8
M34 2B2B2B2B OCLPer02:42.0+42:47 5.2----21.535
M77 2C3C3C4D GALCet02:42.7-00:01 8.918.421.67.1x6.0

For a key to this table, see Key to the Tables.

With the exception of M77 and M74, all of these objects have far northerly declinations, and so remain well-placed for a very long time for observers in the North Temperate Zone, starting typically in the late summer and extending well into the winter, or even the early spring.

Several of the objects listed in the early autumn section are also far north, and remain visible throughout autumn. And M45, the Pleiades, harbinger of the winter sky, can be seen rising in the east throughout autumn from northern latitudes.

M31, M32, and M110

M31, the Andromeda Galaxy, is the largest and brightest member of the Local Group of galaxies, with our own Milky Way not far behind. It is also the only galaxy which is genuinely easy to see from the Northern Hemisphere, even with tiny instruments and even under heavy light pollution. The two Magellanic Clouds, our nearest galactic neighbors, are much brighter even than M31, but they are visible only from the Southern Hemisphere.

Like our own Milky Way, M31 is a spiral galaxy, but we see it from a rather awkward angle, which makes the spiral structure hard to discern even in the best astrophotographs. Some galaxies, like M33, M51, M83, and M101 are face-on spirals oriented nearly perpendicular to our line of sight, so that we see the spiral pattern laid out neatly along the sky. Others, like M104, are edge-on spirals oriented nearly parallel to our line of sight, so that we see them as thin lines across the sky with a central bulge in the middle. We see M31 neither face on nor edge on, but at a shallow angle, so that the face of the disk is visible, but appears as a highly elongated ellipse. The dark lanes between the spiral arms are visible, but barely.

M32 and M110 are the two brightest satellite galaxies of M31, as the Magellanic Clouds are satellites of our Milky Way. M32 and M110 are both classified as elliptical galaxies, and they are nearly identical in total brightness, but the similarities stop there. M32 is tiny and intense, with an extremely bright core, while M110 is huge and diffuse, with no core worthy of the name. They rank near the top and bottom of all the Messier galaxies in surface brightness.

There are two classic ways to locate M31. For people not familiar with the sky who are using wide-field instruments like binoculars, M31 can be located with respect to the Pole Star and Cassiopeia. A line from Polaris through Alpha Cassiopeiae, continued on for 50% of that distance, lands almost directly atop M31. But since this is a 15-degree jump through the sky, you are unlikely to land M31 inside a telescopic field of view using this method.

A much more precise method is to start with the bright star Beta Andromedae, just 8 degrees from M31. It is well worth learning the constellations of Andromeda and Pegasus, which dominate the autumn sky. They are connected through the star Alpha Andromedae (Alpheratz), which is tecnically in Andromeda but is also one of the four stars composing the Great Square of Pegasus. The whole thing forms a vast asterism which I like to think of as the Truly Gigantic Dipper, shaped very much like the Big Dipper, but twice as big. Projections from Polaris through the stars of Cassiopeia, and then continued for an equal distance, very nearly outline the bright stars of Andromeda.

In decent urban skies of better, you should be able to see Mu Andromedae, the mag 3.9 star 4 degrees NW of Beta And. A line from Beta through Mu and continued another 4 degrees lands directly atop M31. Slightly SE of M31 is Nu Andromedae, mag 4.5. If you can see Nu, it is likely that you can also see M31 itself with your unaided eye. It sometimes appears to me as a faint, smallish cloud, and sometimes as a nearly stellar object. It is worth a look, because at nearly 3 million light years, M31 is the most distant object visible to the naked eye without major effort. If you cannot see M31 without aid, even the tiniest optical instrument, such as opera glasses, should show it as a faint cloud of light.

Under urban skies, little more than the core of M31 is visible. In my 70mm scope, it shows much the same at all powers, as a very bright, slightly elliptical patch, about 5' by 4'. I can see somewhat more of the core in my 178mm scope, especially at higher power, plus a very faint extension to the SSW. In the larger scope, it is also apparent that there is an intense, nearly stellar nucleus near the center.

Under suburban skies, much more of M31 is visible in both scopes. The core is embedded in a huge faint glow about one degree long from SW to NE, but much narrower, perhaps 6' to 8' at the widest in the 70mm scope and 10' to 12' wide in the 178mm scope, and tapering towards the ends. M31 is a spiral galaxy, and this extended glow is the inner part of the disk. If you correlate the telescopic view in the suburbs to a photograph, it will be apparent that you are seeing the portion of the disk inside the first dark lane, the hub where the spiral arms join together.

The extended glow is brighter on the SW side of the core, but extends much farther on the NE side, well out of the field at 60X when the core is centered. To see maximum detail, I find it advisable to use fairly high magnifications, at least 80X or 100X in my 178mm scope, and scan around the galaxy, seeing only a small part at one time. However, the low-power view, fitting as much as possible of the galaxy and its companions, is equally rewarding in a different way.

In the 178mm scope under suburban skies, it is apparent that the extended disk stops much more abruptly on the NW edge than on the SE edge. This is due to the inner dust lane, which blots out the disk quite effectively. Under darker skies, you can see another much fainter patch of light on the NW side of the inner dust lane, then a second much subtler dust lane to the NW of that, and after that, only the faintest hint of light.

M32 is visible about half a degree due S of M31's core, forming a striking, nearly rectangular shape with three nearby stars of similar brightness. M32 is easy to see even in very small scopes and under heavy light pollution, but at low magnifications, it can be hard to distinguish from a star. It appears as a point or tiny circle of bright light, with a slightly hairy or fuzzy appearance. Some people believe that the highly condensed appearance of M32 is due to the fact that the outer portions of this galaxy have been stripped away by the tidal forces of its much bigger neighbor. In fact, M32 appears very much like an enormous globular cluster.

Under dark skies, huge M110 is much more prominent than tiny M32, but it is nearly invisible under serious light pollution due to its low surface brightness and the almost complete absence of a bright central core to grab the eye. In fact, I sometimes think that M110 is the hardest of all the Messier objects to see under very bright skies. All three galaxies show easily together in one low-power field under dark skies, but under bright skies, it is better to use fairly high magnification, and to starhop to M110's presumed location from M31's core, then start applying averted vision.

Seeing M110 under urban skies is a real feat. It appears as an extremely subtle, elusive patch, barely brighter than the background, about 5' by 3', extended N-S. Because M110's difficulty is due almost entirely to low surface brightness and not low total brightness, it is very nearly as easy (or hard) to see in my 70mm scope as in my 178mm scope.

M110 is still subtle under suburban skies, but fairly obvious once you have found it, a nearly featureless patch of light, uniformly bright, about 6' by 4' or perhaps slightly larger, with no clearly defined center or edges. Again, the view is quite similar in my 70mm scope and my 178mm scope.

M33

Our Local Group of galaxies is dominated by three big spiral galaxies: M31, the Milky Way, and M33. M33 is much the smallest and faintest of the three, but it is still quite a bit bigger and brighter than the average galaxy. M33 is unusual among spiral galaxies in that it does not seem to have a massive black hole at the center. This may be related to the fact that its central core is unusually small and faint compared to the brightness of the disk. M33 is quite close in space to M31, which is reflected in the fact that they appear quite close in the sky from our perspective, but it is not quite close enough to count as a satellite galaxy.

Unlike M31, M33 happens to be oriented nearly perpendicular to our line of sight, so that the spiral pattern is clearly visible in astrophotographs, or when M33 is seen through a medium-to-large telescope under truly dark skies. One of my proudest feats of suburban observing was detecting unmistakeable signs of the spiral pattern in my 178mm scope.

Because of its proximity to our Milky Way, M33 is second highest among all of the Messier galaxies in total brightness, but due to its enormous size, it also ranks third from the bottom in surface brightness. This makes M33's visibility famously paradoxical. Under dark skies, M33 is one of the easiest galaxies to see in small instruments; it is not especially hard to see with the unaided eye, and is very easy to see in small binoculars. (Easier in binoculars than in a telescope, many people say.) Under even modest light pollution, however, M33 is notoriously difficult to see even in large instruments, due to its low surface brightness.

Actually, I do not find M33 quite as hard to see as the surface brightness would predict. Partly, no doubt, that is because the theoretical size of 71 by 42 arcminutes grossly over-states what one sees through a telescope. Yes, M33 is enormous, but even under superb skies, M33 appears no bigger to me than 40 by 25 arcminutes, less than one third of the size as determined from photographs. Moreover, although M33's core is abnormally faint compared to the galaxy as a whole, it is big enough and bright enough to show up reasonably well even under urban skies unlike, say, the core of M101.

Given M33's subtle appearance under urban or suburban skies, it is definitely advisable to starhop to it rather than using a point-and-shoot method. The nearest reasonably bright star is Alpha Trianguli. Under good suburban skies, Alpha can be seen to form an attractive elongated triangle together with Beta and Gamma Trianguli to the E, but this triangle does not stand out well under urban skies. The triangle is just small enough to fit in the field of standard 7X binoculars, which will also neatly split mag 4.9 Delta Trianguli from nearby Gamma. If you cannot make out the triangle, Alpha can be found 2/5 of the way from bright Alpha Arietis to Beta Andromedae, the jumping-off star for M31. From Alpha Tri, it is a modest but slightly awkward starhop over 4 degrees of fairly blank sky to M33.

Since M33 itself can be hard to discern, you should look first for an elegant quadrangle about 35' long and 25' wide composed of three mag 8.1 stars and a mag 9.3 star at the N corner. The core of M31 lies slightly to the E of the center of this quadrangle.

Under urban skies, M33 shows best at moderately low magnification, around 20X - 30X in my 70mm scope or 40X - 80X in my 178mm scope. It tends to fade out at higher powers. What I see in both scopes is a large, vague blob of light about 10' by 8' elongated N-S, with no clear center or edges. It swims into ghostly existence when I scan with averted vision, and disappears when I look directly at it.

M33 is much easier to make out under suburban skies, although it still shows best with averted vision. In fact, M33 is not terribly hard to see in my 7x35 binoculars under suburban skies, not much harder than in my telescopes. Although easier to see, the view in my 70mm scope is not much different under suburban skies than under urban skies. The 178mm scope, however, begins to reveal significant additional detail. At first, the impression is just of a moderately faint 5' circle surrounded by a much fainter cloud about twice that diameter and slightly elongated N-S. Then, scanning methodically with averted vision at 100X, I see a smaller and fainter concentration about 10' S of the core, and a broad triangle of extremely faint light stretching through that secondary concentration and pointing S. On the N side, I see a very faint, fairly thin thread of light reaching first NE and then bending almost due E. Comparing this impression to the photographs, I see that the E edge of the triangle on the S is one of the spiral arms, and the ethereal thread to the N is the other.

Not far from the end of the N arm, but a little farther out, some 12' NNE of the core, is a truly extraordinary object: the extragalactic emission nebula NGC 604. It is actually quite easy to see in my 178mm scope even under urban skies, in some sense easier than M33 itself, because it has very high surface brightness. However, it is also easy to miss because it lies surprisingly far from the central part of M33, and easy to overlook because it appears incredibly small, barely non-stellar even at 100X.

NGC 604 is an emission nebula within the N arm of M33, an object very much like the Orion Nebula, but some 1500 times as distant, and incredibly much bigger and brighter to be so readily visible at such an enormous distance. Indeed, NGC 604 is one of the inherently brightest emission nebulae known in the entire universe.

M74

The galaxy M74 is a strong contender for the title of hardest Messier object to see. It is low both in total brightness and in surface brightness, making it hard both for small instruments under dark skies and for large instruments under bright skies. It also has an abnormally small and faint core compared to the rest of the galaxy. If you ever get to see it with a really big scope under truly dark skies, it will be apparent that M74 is a face-on spiral with faint, tightly wound arms studded with emission areas, very much like M101 but on a much smaller scale.

Fortunately, M74 is quite easy to locate, being just 1.3 degrees ENE of mag 3.6 Eta Piscium, and forming a nearly equilateral triangle with that star and mag 6.2 101 Piscium to the S. If you have trouble finding Eta Psc, first find Aries, the most prominent constellation in this part of the sky. A line from Alpha Arietis through Beta Arietis points slightly N of Eta Psc.

Because M74 is unlikely to be apparent at first sight, it is a good idea to first locate the line of 5 stars ranging from mag 10.5 to mag 12.0 slanting from 17' due E of M74 to 20' NW. Then you must apply averted vision in the area S of the largest gap in that line of stars.

In my 70mm scope, M74 is difficult under dark skies, extremely difficult under suburban skies, and invisible under urban skies. It shows up best at around 60X, and requires both averted vision and carefully controlled breathing. When seen, it is actually fairly large, several arcminutes across and nearly circular. I might think that the suburban view was an illusion if not for the fact that it moves when I move the telescope. Moving the scope also helps the object appear in the first place.

M74 is nearly as difficult using my 178mm scope in the city. Again, it responds best to fairly high power (120X or higher), and again it requires averted vision and controlled breathing. M74 is much easier in the 178mm scope under suburban skies. It still requires averted vision, but it is reasonably solid once seen, and less prone to fade out unexpectedly. The best view under suburban skies is at somewhat lower power, around 80X, where M74 appears as a vague featureless circle about 4' across.

M76

M76 is another notoriously difficult Messier object, but its difficulty lies entirely in low total brightness; it is near the top in terms of surface brightness. Therefore, M76 is quite hard to see in small instruments under any conditions, but is quite easy and attractive in large scopes even under very bright skies. M76 is a planetary nebula, shaped quite similarly to M27 but much smaller and with somewhat higher surface brightness. Hence M76's nickname of the Little Dumbbell, where M27 is just the Dumbbell.

M76 lies just one degree N of the mag 4.0 star Phi Persei. If you cannot see Phi Per directly, try looking first for mag 3.6 51 And 2 degrees to its SSW. A mag 7.8 star lies just 5' S of Phi Per, and a line from that star through Phi Per lands directly atop M76. Even if you cannot see M76 itself immediately, the field is easy to recognize by the reddish mag 6.7 star 13' to the ESE of M76 and the mag 9.5 star 8' to the WSW. Both stars fit easily with M76 even in a high-power field.

I have several times tried and failed to see M76 in my 70mm scope under urban skies; apparently, it is just too faint to detect under such conditions. Using the 70mm scope in the suburbs, M76 is quite faint, requiring averted vision, but unmistakeable. It appears very small and has no hint of detail except a slight elongation N-S. The best view is at around 60X.

M76 is quite easy to see in my 178mm scope, readily perceptible with direct vision even at low powers and under heavy light pollution. The best view is at high power, around 120X, where it appears as a bold, clear dumbell or hourglass shape, about 2' by 1.5' elongated NNW to SSE. The shape is marginally clearer when I use my UHC filter, especially under urban skies.

M34

M34 is a large, bright, coarse open cluster, a pleasant change from faint galaxies and miniscule planetary nebulae. It shows well under bright skies and in small instruments, and is fairly easy to see with the unaided eye under exurban or rural skies.

M34 is fairly easy to find by the point-and-shoot method, lying about 1 degree N of a line connecting Beta Persei (Algol) and Gamma Andromedae (Almach), about 40% of the way from the former to the latter. Both Algol and Almach are unusual stars. Algol (meaning The Demon) shines at mag 2.1 most of the time, but for 10 hours every 3 days, it slowly fades to mag 3.4 and then returns to its normal brightness. This variation is due to an unseen companion which orbits around the primary star and periodically passes between us and the primary, blocking some of the light. Almach is an attractive wide double, easily split at 60X, with a blueish secondary about 2.5 magnitudes fainter than the yellowish primary.

If you cannot find M34 by point-and-shoot, you are faced with a rather onerous 6-degree starhop from Algol, as no reasonably bright star lies significantly nearer.

Although M34 is quite bright, its stars are scattered over more than half a degree of sky, and the background stars are also fairly rich. Therefore, M34 stands out best at low power, which compresses its stars and shows them off against the widest possible background. M34 is small and tight in my 7x35 binoculars, especially under suburban skies or better, where five of the stars resolve easily.

The best compromise between framing and seeing detail seems to be around 60X both in my 70mm scope and in my 178mm scope. About two dozen stars in a 35' circle are visible in the smaller scope at that power, but some of them are extremely faint under urban skies. In the 178mm scope, some three dozen stars are visible in the same area.

Near the center of the cluster is a U-shaped asterism of 8 mag 8 and mag 9 stars, open to the ESE, about 6' by 4'. At the NW end of the U is the attractive double star John Herschel 1123, with nearly equal mag 8 components separated by 20", and fairly easily split even at 16X. This double star also forms one corner of a tiny dipper-shaped asterism of mag 9 and mag 10 stars lying within the U.

M77

M77 is a Seyfert galaxy, akin to a quasar but not so extreme, with much or most of its radiation emitted by an active nucleus whose size is infinitessimal compared to the galaxy as a whole. According to current theories, the nucleus is powered by a dense cloud of gas spiralling into a black hole.

Because of the active nucleus, M77 has high surface brightness and an intensely bright core, making it readily visible even under very heavy light pollution. However, light pollution can obliterate the outer disk, making it hard to distinguish M77 from a star.

M77 lies one degree WSW of Delta Ceti, a mag 4.1 star that can be rather hard to locate under bright skies. If in doubt, the best place to start is with Alpha Ceti, a reddish mag 2.5 star that is much the brightest in that part of the sky. Starting with Alpha, it should be easy to locate mag 3.5 Beta Ceti some five degrees to the W, and possibly some of the four fainter stars which compose the head of Cetus, the Whale, together with Alpha and Beta. 7x binoculars help a lot in making out the head, although they won't quite fit the whole thing in one field of view. Delta Cet lies 3 degrees SSW of Beta.

If you cannot see M77 immediately one degree ESE of Delta Cet, look first for the line of mag 9 stars just to its NE. M77 lies just where one might expect a fourth star to lie if the line contained four stars.

In my 70mm scope, M77 is a bit hard to see under urban skies, requiring averted vision at 60X. It is considerably easier under suburban skies, where direct vision suffices. In both cases, it shows as a faint, slightly hairy star.

M77 shows much better in my 178mm scope, which has enough aperture to make M77's core appear like a brightish star. To confuse matters, there is a real mag 10.8 star, nearly identical in brightness to M77's core, lying just a couple of arcminutes to the E. M77's core is surrounded by a faint haze some 3' in diameter, nearly reaching to the neighboring star. The view is nearly identical in the city and the suburbs, except that the haze is more pronounced in the suburbs.