Star Atlas
[1] The region of the sky containing the
constellation of Scorpius, imaged by the
European Space Agency.[2] This is a 340-million-pixel vista of the
central parts of our galactic home, a 34 by
20-degree wide image. It shows the region
spanning the sky from the constellation
of Sagittarius, the Archer, to Scorpius, the
Scorpion. The very colourful Rho Ophiuchi
and Antares region features prominently
to the right, as well as much darker areas,
such as the the Pipe and Snake Nebulae.
The dusty lane of our Milky Way runs
obliquely through the image, dotted with
remarkable bright, reddish nebulae, such as
the Lagoon and the Trifid Nebulae, as well
as NGC 6357 and NGC 6334. This dark lane
also hosts the very centre of our Galaxy,
where a supermassive black hole is lurking.
ESO/S. Guisard.Delta Cephei or Eta Aquilae. It was this which initially misled Edwin
Hubble when he was trying to measure the distance of the Andromeda
Galaxy. He used Cepheids as "standard candles" but he did not know and
had no means of knowing that there were two separate kinds of Cepheid
and he had picked the wrong one! This is why his initial estimates for the
distances of the spiral galaxies were much too low, though still great
enough to demonstrate that they were remote systems and not inside
our own galaxy.Tucana, the Toucan
Tucana has one splendid globular cluster 47 Tucanae, which appears
to be silhouetted against the Small Magellanic Cloud. This is highly
misleading because the globular is a member of the Milky Way Galaxy
whereas the Small Magellanic Cloud is a satellite of the Milky Way and at
a very much greater distance.come to a very rich region of the Milky Way together with one lovely star
cluster, M11, known as the Wild Duck Cluster.
Delphinus, the Dolphin
Below and to the east of Altair look for Delphinus, the Dolphin, which is
sometimes confused with the Pleiades open cluster in Taurus, despite
not being as bright or as compact as the cluster. Next, let us find the
Southern Birds. There are several of these – Grus the Crane, Pavo the
Peacock, and Tucana the Tucan. The most distinctive of these is Grus,
where there are two second magnitude stars Alnair and Beta Gruis, and
a whole line of fainter stars which give the impression of being wide
doubles, though they are merely optical pairs.
Pavo contains a star called Kappa Pavonis which, for a long time,
was regarded as a Cepheid variable of a type once known as a Type II
Cepheid. This is much less luminous than a classic Cepheid such as