4.1 KiB
| name | created_by | created_date | updated_by | updated_date |
|---|---|---|---|---|
| Ophiuchus | skybber | 2021-07-10 14:48:05.710581 | skybber | 2022-02-11 18:16:46.353752 |
A large equatorial constellation of the summer sky, stretching between Hercules and Scorpio. The ecliptic passes through the southern part of Ophiuchus, which is why Ophiuchus is also sometimes referred to as the "13th constellation of the animal". The Sun is here in the first half of December each year, specifically from November 30 to December 17. Ophiuchus lies almost exactly in the middle of the sky: between the north and south poles and between the spring and autumn points.
There are five stars of magnitude greater than three in Ophiuchus, but it's an extremely spread out and uncluttered summer constellation, but well worth exploring with a good map and at least some sort of binocular. In its northeastern part, a split branch of the summer Milky Way extends into it, while its southernmost parts delve into the rich region between Sagittarius and Scorpius, near the centre of the Galaxy. Because most globular clusters are concentrated around it, there are many - over 20 - in the constellation. Ophiuchus also contains typical Milky Way objects such as open clusters, emission and dark nebulae.
The most important and prominent dust complex is the large dark formation Pipe nebula (LDN 1773). Its mouthpiece is clearly visible as a roughly four-degree notch from the eastern side into a less conspicuous, but still easily visible bulge to the west of the Galactic plane. It is formed by the Barnard system of dark nebulae 77, 78, 59, 65, 66, 67 on the borders of Sagittarius, Ophiuchus and Scorpio and transforms in triads into a region virtually devoid of any bright stars. Start looking for the pipe about twelve degrees east of Antares at the line of three 3-4mag stars, the only really conspicuous ones in the area. The brightest of these - θ Ophiuchi - lies in the middle of this line. The head of the Pipe is located three degrees SSE of it, the mouthpiece extends two degrees down below θ Oph and terminates three and a half degrees southwest of 36 Ophiuchi, the westernmost star of the line. The globular cluster M19 also lies a short distance to the VSV.
The plume, by the way, forms the hind legs and part of a much larger dark structure that has come to be referred to as the Dancing Horse, especially in Anglo-American countries. It can be found roughly midway between M24 and the star Antares and is easily seen, especially with the naked eye. The whole complex consists of the following parts: Barnard 64 and 259 (the nostrils of the horse), B 268 and 270 (the mane), B 47, 60 and 63 (the forelegs and the kupyto), B 262, 266 and 269 (the lower parts of the forebody), B 77 (the abdomen), B 78 (the hind part) and finally B 65-67 (the hind legs). The rider starts still in Ophiuchus and ends in Sagittarius near Trifid. We'll play with the dark nebulae some more. The surrealistically long extension of the horse's foreleg, winding down to the ρ Ophiuchi complex, also represents the so-called Dark River (B 44, 45, 46, 47, 51, 60, 253). This begins roughly at the star 22 Scorpii, is about half a degree wide and ten degrees long, gradually widening into a breaking chain of dark regions. All the while, this huge physically related complex is one of the darkest. The incoming starlight is dimmed by up to 30 magnitudes in some places. That's enough to keep us from seeing a massive supernova explode!
In the northern part of the constellation, the brightest part of the Milky Way is around the open cluster NGC 6633, which is visible to the naked eye as a distinctive circular spot. To the east of it is the angularly larger but less conspicuous cluster IC 4756, which may also be visible without binoculars. Stellar clusters 66, 67, 68, 70 and 73 Ophiuchi are arranged in a small V-shape. This is Poniatowski's Taurus, an old but no longer extant constellation introduced in 1777. To the northeast of it, and next to the star β Ophiuchi, lies another open cluster - IC 4665. To the naked eye, it appears as an unmissable moon-sized hazy spot on the edge of the Milky Way.