Star clouds and dust in Sagittarius/Ophiuchus
AAO image reference UKS 38.    « Previous || Next »

Star clouds and dust in Sagittarius/Ophiuchus
Top left is NE. Image width is about 4.3 degrees.
© 2010, Australian Astronomical Observatory. Photograph by David Malin from UK Schmidt Telescope plates.

It is rather obvious to say that the Milky Way is rich in stars, and so it is, but not uniformly. The central regions, in the constellations of Sagittarius, Ophiuchus and Scorpius are the richest, but again not uniformly. On the southern side of the Milky Way, the star clouds of Sagittarius are the brightest parts and are clearly visible in the middle months of the year. This is the central bulge of our galaxy, as we look towards the Galactic centre.

The Milky Way's dust lane seems to divide it into two parts. On the northern side the density of stars should be similar to that on the southern side, but it is not. This is probably because the Sun is displaced from the Galactic plane by 100 light years or so, and we therefore see the 'northern' bulge through the dust of a spiral arm in the direction of Scorpius and Ophiuchus.

The picture above covers over four degrees of arc of the sky about 6 degrees from the Galactic plane. The western (right) side of the image borders the enormous dark cloud Barnard 78, while the brightest star-like object is the globular cluster NGC 6401. The formal boundary of Sagittarius and Ophiuchus runs north-south, roughly through the centre of the photograph, which is also crossed by the ecliptic, running east-west. A wide angle picture of this part if the sky including the ecliptic and the constellation boundaries is here.

Related images
UKS 20. The star clouds of Sagittarius
AAT 28.  The brightest part of the Milky Way
Constellation of Sagittarius (external site)
Constellation of Ophiuchus (external site)
Constellation of Scorpius (external site)

For details of object position and photographic exposure, search technical table by UKS reference number.

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Updated by David Malin, 2010, July 25