3.3 KiB
| name | created_by | created_date | updated_by | updated_date |
|---|---|---|---|---|
| Cassiopeia | skybber | 2021-06-06 08:41:35.776601 | skybber | 2022-02-11 18:35:27.035219 |
A constellation near the North Pole, it is circumpolar in our latitudes. It's one of the constellations we can easily identify in the sky. Five bright stars form a characteristic "W" or "M" shaped constellation in the star-rich Milky Way, on the opposite side of Polaris from the Big Dipper. Cassiopeia is crossed by the autumn Milky Way and the constellation is therefore also extremely rich in open star clusters. Some are among the most beautiful in the sky, while others are only tiny groups or clusters of stars nestled in rich star fields, and are therefore not easy to discover and correctly identify. Without a detailed constellation map, we can quickly get lost in this area. The constellation is also decorated with a few nebulae, a few galaxies and a large number of colourful double and multiple stars.
We look into the constellation Cassiopeia and its surroundings in the direction of galactic rotation, but out of our arm. Because there are no large clouds of interstellar material in this region, we can admire the arm of Perseus in our autumn sky. This is the main outer arm, lying furthest from the centre of the galaxy. It's wide, ragged and merges with the Orion arm in places. Rather than encircling the Galaxy in a continuous line, it is a series of disconnected clouds of young stars and nebulae. Seen from a distance, it would appear as a faint arm with many concentrations of young stars and nebulae. Unlike the Sagittarius and Ruler arms, however, it does not have a major effect on the appearance of our Galaxy.
Let's follow the course of the Milky Way in the sky. The main stream continues through Cassiopeia and cuts directly through the five bright stars of the constellation. It is very uneven, tapering off a little and losing a little intensity. It is sharply defined in the northern part, but in the south it passes very smoothly into its surroundings, and in a side view almost touches the Great Nebula in Andromeda during excellent conditions. Its brightest part is a narrow belt stretching from stars 1 and 2 Cas to stars 9 and 10 Cas. This belt is flanked on the south side by a single oval, slightly conspicuous brightening, on the edge of which lies the open cluster M52, which is not the easiest to observe with the naked eye, and is sometimes confused with a small conspicuous brightening in its neighbourhood, which is only a chance grouping of about four faint stars.
A few brighter areas and a few darker areas are still visible in the main stream, the most striking of which is the oval bay penetrating the main pattern of the constellation to the star δ Cas. Conversely, there is a small brightening near γ Cas, and a small hazy circular patch is visible to the naked eye just off the ε Cas star. On closer inspection, the triangle of stars 52, 53 Cas and HR 657 (magnitudes 6.0 - 5.6 - 5.3) can be easily distinguished. In the southern part of the constellation, on the other hand, a large group often referred to as Stock 2 is an ideal object for the binocular. It consists of about 50 stars of 9th and 10th magnitude covering an area of the sky of one degree.
Translated with www.DeepL.com/Translator (free version)