Moondark for September: The Milky Fly-Way  

Ever since our distant ancestors looked up, they have wondered about the hazy band we call the Milky Way. From a truly dark site, it can be mistaken for a cloud that will not dissipate, fixed to the celestial sphere in its nightly march across the sky. Today’s astronomers know the glowing circle of light to be the insider’s view of the disk of our own home galaxy.  

The Greeks believed that drops of breast milk for the infant Hercules flew upward to the sky. Australian Aborigines regarded the arc of light as a river in the Sky World, with bright stars as fish and dimmer ones as lily pad bulbs. To me, as I look up, it seems more like a celestial flyway for the winged creatures of the sky.  

This is plain enough under a late summer sky. See the constellations of Cygnus the Swan, and Aquila the Eagle, flying south along the Summer Triangle? Since antiquity these constellations have been seen as birds with a rich lore and mythology. Even Sagitta, the Arrow, flies between these starry birds. And just to the east--what’s that? A Winged Horse, Pegasus!  

 
Now look closer, for the Swan Nebula (Messier’s 16th), the Eagle Nebula (M17) and the Wild Duck Cluster (M11). Never mind that these are really stellar nurseries, revealed as “pillars of creation" in detail by the Hubble Space Telescope.  
  
And insects too: the Butterfly Cluster (M6) and Bug Nebula (NGC 6302) in Scorpius. I would even propose more revisionist astronomy: I see the Dumbbell Nebula (M27) is a moth attracted by the glow of the Milky Way, flitting between the star clouds of Cygnus and Scutum and Sagittarius. Below our horizon, Musca the Fly hovers near the Southern Cross, and Apus the Bird of Paradise circles the south Celestial Pole.  

Now rising far to the north, the Owl Cluster (NGC 457) is one of many such clusters in Cassiopeia. This fall sky heralds a change of seasons. Both the feathered and the starry creatures will soon head south, each along their own flyways.  

Image captions: From north to south, top to bottom along the Milky Way: M11, M16, M17 and M6. I took these images while cruising the flyway with a CB245 CCD on a 20-cm Schmidt-Cassegrain at f/6.3 or 80-mm refractor at f/5 (M6 only).  
Moondark is written by Doug Miller and published both electronically and in hard-copy form in the Star Gazer News for the Delmarva Star Gazers. Please address comments and suggestions to dmiller@udel.edu. This document was last revised on 23 August 1998. All text and images copyright © 1998 Douglas C. Miller, All Rights Reserved. This material may not be reproduced in any form without prior permission.