Hawaiian Astronomical Society

Constellations: Corona Australis -- Passion run Amok

Myth

The house of Cadmus was many times cursed. You remember Cadmus? The man sent after his sister, Europa, but who followed a cow, fought a dragon, sowed its teeth, founded the house of Thebes, and married Harmonia, daughter of the gods Ares and Aphrodite. Cadmus lived a tough life, but spent many years blissfully married. The gods, however, never allow mortals to remain happy. Cadmus had four daughters and a son. The son's name was Polydorus. the daughters were Ino, Semele, Autonoe, and Agave. Most came to bad ends. Blame Zeus. He started it by abducting Europa. Now he fell in love with Semele.

Zeus kept his affair with her secret long enough to get her good and pregnant. When Hera, his wife, eventually discovered it, her desire for revenge could not be satisfied. During Semele's sixth month of pregnancy, Hera appeared to her, disguised as her maid. She urged Semele to ask Zeus to appear before her, just as he appeared before Hera. Later, when god and mortal lay together, Semele made Zeus promise on the River Styx to grant a favor. Then she made her request. Zeus was horrified, but felt forced to comply. Sources say Semele died either of fright, or was struck by lightening, and her soul fled to Hades.

Zeus busied himself with her dead body. He ripped her open, took the six month old foetus, and placed it in his thigh to bring it to term. He called the baby Dionysus. Ino, Semele's sister, agreed to raise it, thereby incurring the wrath of Hera. Hera descended to Hades to ask the Furies for help. They drove Ino and her husband mad, causing them to murder their own children. Zeus then took Dionysus to the nymphs of Nyssa. Eventually Dionysus retrieved his mother from the underworld, named her Thyone, and placed her crown in the sky. The Romans called her Stimula, goddess of female passion.

And what of the others? Cadmus and Harmonia ended their lives in exile, turned into snakes. Their grandson, Pentheus, became king, and was torn limb from limb by his mother, Agave (Semele's sister) in a Dionysian frenzy. Polydorus became the next king of Thebes. Autonoe had a son, Actaeon, who also was interested in Semele. Some sources say Zeus arranged for him to spot the goddess Artemis naked in the woods. Artemis turned him into a deer, to be killed by his own dogs. Autonoe went into exile for grief at the loss of her son.

Maps

Each map can be clicked on to produce a 916x1200 version of it. They sport red labels, which look good on screen, but which disappear when used with red flashlights. Each map, therefore has a second link to a map better suited for printing in a graphics program, and using in the field. While they are quite large, they are all about 50-55k, and so are easy to view at today's modem speeds. The first map is a wide area view of the constellation, suitable for naked eye browsing. The next views are binocular width, showing stars to mag. 10, and labeling deepsky objects to magnitude 12.

Interactive, wide area map of Corona Australis

Click the map for a 912x1200 version of the above. Click here for a map better suited for use in the field.

Detailed View

Click here for a map better suited for use in the field.

Images

16k JPEG Caldwell 68 (NGC6729) is a combination reflection and emission nebula around the star R Coronae Australis (mags. 9.7-13.5). Just north are the related reflection nebulae NGCs 6726-7. The latter are 9'x7' in size. NGC6729's size is variable, and while not difficult, it is less bright than its siblings to the north-west.

Map	Printable Map

Image thumbnail 24k JPEG NGC6541 (Bennett 104, Caldwell 78) is a globular cluster located in the constellation's south-west corner. Dreyer calls it bright (mag. 6.6), round (13'), extremely condensed overall, with a gradual brightening middle. Stars are from mag. 13 and fainter. This and the above image are from the Digital Sky Survey.

Map Printable Map

Image thumbnail 48k JPEG NGC6496 (Bennett 100) is a mag. 9.2 globular cluster located in south-western Corona Australis on the border with Scorpius. Dreyer calls this a "nebula plus cluster," one that is fairly large (6.9'), much elongated, and brightening only quite slowly toward the middle. It's appearance through a 12" includes a patch of haze with a few scattered stars resolved. The resolved stars most likely sit in the forground. A 4" shows only the haze. Image is from the Digital Sky Survey.

Map Printable Map More info.

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