big-dipper-web.jpg

This is a photo I took of the big dipper. More photos are here.

Here is a practice drawing from Starry Night.

Here is Van Gogh’s impression of the Big Dipper. One of the first asterisms many people learn to recognize is the seven-star Big Dipper, consisting of the seven brightest stars of Ursa Major, the great bear. These stars are, starting with the end of the dipper’s handle (or end of the bear’s tail), Alkaid, Mizar (with its fainter optical companion Alcor), Alioth, and then clockwise around the bowl starting with where the handle joins it, Megrez, Phecda, Merak, and Dubhe. In addition to the Big Dipper asterism are less-familiar portions of the bear. Three medium-bright stars form the bear’s nose, and a pair of triangles of stars and a third very skewed triangle (nine total) form three visible paws. The bowl of the dipper looks like a saddle on the bear’s back. Here is a map of Ursa Major.

Nearby constellations

The bear seems to be chased by Canes Venatici (hunting dogs–directly below Alkaid if viewing the dipper so the bowl faces up–see the bright star bottom center of the photo at the beginning of the post). It seems to be walking on the little lion, Leo Minor. It is sniffing out the hard-to-see lynx. The dragon (Draco) winds between the big and little dippers. Bootes the herdsman seems to be chasing the bear away.

Galaxies

Ursa Major is home to many galaxies, it being well outside the galactic plane (visible as the Milky Way) so one has a clear view out of our galaxy. M81 (Bode’s Galaxy) is one of the brighter galaxies in the sky, just visible to the naked eye under very good conditions. It is next to M82, the Cigar Galaxy, and in fact, the two recently had a close encounter that disrupted both galaxies. In addition, M101 (Pinwheel Galaxy) is near Alkaid (so is the Whirlpool Galaxy, M51, though technically, it is in Canes Venatici). Other galaxies in or near Ursa Major include M97, M108, M109, and nearby M63, M94, and M106 in Canes Venatici.

History and Mythology

Ursa Major may be one of the oldest constellations. American Indians, Australian Aborigines, and ancient Romans all saw it as a bear, and the three cultures had not interacted for thousands of years. It may be 50,000 years old even (to a time when humans worshiped bears). See AAVSO’s notes on the subject.

In any case, the Greek myth was that Zeus fell in love with Callisto. Zeus’s jealous wife turned Callisto into a bear (Ursa Major) out of revenge. Later, Arcas, Callisto’s son by Zeus, nearly killed her in a hunt (unknowingly) but Zeus intervened by turning Arcas into a bear (Ursa Minor) and placed them both in the sky.

See Wikipedia’s article for more information.

It’s been cloudy and rainy (except for a few brief moments of sunshine) for almost a week now! I’m sure there are stars up there somewhere, but I can see no evidence from here. It’s times like this that “blimp telescope” idea sounds good. So… here is my sketch of M51 through binoculars. This one was faint, very hard in light pollution, even in a telescope. I have an older observation on the same page where I did not see M51. Incidentally, though I did not draw it then, M51 was very prominent in binoculars in Hardy County, West Virginia.

Deneb, or Alpha Cygni is one of the three stars of the summer triangle and is the “top” of the northern cross. Because Cygnus is in the Milky Way, you see a rich starfield in binoculars–the drawing doesn’t begin to do justice to the Deneb starfield, especially under a dark sky. Many stars you cannot actually see, but your eyes still detect that they are there; there is a “sensation” of far more stars than you can actually resolve. Partly, this is the nebulosity of the faint starglow, and partly, the stars do come into vision, especially averted vision, briefly and disappear. This is an older observation, as tonight is rainy and cloudy with storms. Tonight was to be a Howard Astronomical League star party, but the weather had something to say about that.

Sometimes the binoculars give a better view than the telescope. That is true with the asterism known as the Coathanger. In the telescope image, some stars are cut off by the narrow field of view, but the whole asterism appears in binoculars. Here is an older observation of Collinder 399, the Coathanger, in binoculars.

I removed the ISP-provided images decorating the pages and replaced them with my own. On the main page, you will see my telescope (edited from a picture taken from a star party with GIMP) replacing the crescent moon. On other pages, you will see a selection of my sketch of Pleiades replacing the gas giants. On the Favorite Links page, the generic galaxy picture was replaced with my Big Dipper creation from GIMP, using the photo I have on the astrophotography page (under Observations). This makes the page more “my own”

The easiest way to find the Beehive cluster (M44) this year is to find Saturn, as the constellation it is in (Cancer) is very dim. If you aim your binoculars at Saturn and move a little left, you will see a collection of stars much like a swarm of bees. The field of view shown includes Saturn and Aselus Borealis and Aselus Australis (literally, northern and southern donkey), which represent two donkeys feasting from a manger (Praesape), another name for the cluster. The central pentagon (house-shaped) is the manger, surrounded by straw on the floor.

The sky is so hazy I cannot even see bright M13 in binoculars. So, here is an older observation. M81 is Bode’s Galaxy, a spiral. M82 is the Cigar Galaxy, an irregular that is dimmer than M81. The two are not just in the same place in the sky, they are close together in space, having recently passed very close to each other and interacted.