Cygnus is the constellation of the Swan, and it is one of the relatively few constellations that looks like its name, a bird with large wings and a long neck. It is supposed to represent Zeus who took the form of a swan to seduce Leda, a mythological queen of Sparta in Greece. As a result of her liaison with Zeus, she gave birth to Helen of Troy. The main stars in Cygnus are also known as the Northern Cross. It lies in the Milky Way and I can remember seeing the Milky Way in Cygnus in Upminster in the 1960s; sadly, this is no longer possible. Below Deneb is a dark region known as the Cygnus Rift. Deneb is a hot A type star and as a result it is a bright star (magnitude 1.3) despite being 2,600 light years away – it is one of the most distant stars we can see with the naked eye. It forms one corner of the Summer Triangle along with Vega and Altair.

Being in the Milky Way, Cygnus contains several star clusters, but here we will only consider the two Messier clusters, Messier 39 and Messier 29. Messier 39 [1] is theoretically a naked-eye object, but is best observed in binoculars, but as it is a sparse cluster, it is difficult to make out against the background of the Milky Way. It has a roughly triangular shape and is roughly the size of the full Moon. It lies halfway between Deneb and the much dimmer Alpha Lacertae (mag. 3.8). It is 280 million years old and is 1,000 light years distant. Messier 29 [2] is easier to locate as it lies just below the bright star Sadr. It is much smaller and dimmer than Messier 39 and looks like a small version of the Pleiades. It is only 10 million years old and lies roughly 5.000 light years away, an enormous distance.

There are several objects in Cygnus which are the province of imagers rather than visual observers. The small emission nebula NGC 6888 or Caldwell 27 (better known as the Crescent Nebula) lies close to Sadr and M29; like M29 it is 5,000 light years from us. The emission nebula called the North America Nebula (Caldwell 20 or NGC 7000) [3] is no less than 13 times the size of the full Moon. With the neighbouring Pelican Nebula (it is in fact part of the North America Nebula, but split visually by a dark cold molecular cloud), the North America Nebula lies between Deneb and Xi (or Ksi) Cygni (mag. 3.7), and may be seen as a slight nebulosity in telescopes, but only images reveal its full glory. It is 2,600 light years distant.

The Veil Nebula [4], Caldwell 33/34, is a supernova remnant which is 36 times the size of the full Moon. I have seen the Witch's Broom Nebula, which is part of the Veil Nebula, in a large telescope in a dark area (it looked like neon lighting), but again it is best seen in images. It is divided into the Eastern Veil, the Western Veil and Pickering’s Triangle (now increasingly named after its actual discoverer Williamina Fleming) in-between; the Witch's Broom is part of the Western Veil. The supernova which formed the Veil Nebula took place between 10,000 and 20,000 years ago, and would have been brighter than Venus when it exploded. It lies 2,400 light years away.

A better object for visual observers is the Blinking Nebula [5] (Caldwell 15 or NGC 6826), so-called because of the alleged blinking effect if one looks at it and then at the side of it. It is small and bluish-green, not unlike the planet Jupiter. It lies about one and a half degrees west of the star Zeta Cygni (mag. 4.5) and is about 2,000 light years distant. The variable star Chi Cygni [6], which lies between Eta Cygni and Albireo, is a Mira-type variable; like Mira, you either see it or you don’t, as it has a maximum of about 4.8 and a minimum of 14. It has a period of 408 days and it peaked in late May 2023. It should peak again on 10 July 2024, when Cygnus is well-placed in the sky.