Navigate the cosmos to discover Cygnus X-1, the elusive black hole, using our handy guide for identifying it in the night sky

In the vast expanse of the night sky, two celestial bodies dance in a cosmic waltz that has intrigued astronomers for decades. One of these objects, HDE 226868 (HIP 98298), is a supergiant variable star that can be observed through a small telescope, shining at mag. +9.0.

However, HDE 226868 is not just an ordinary star. It is, in fact, a companion to a black hole known as Cygnus X-1. From an observational standpoint, Cygnus X-1 is essentially invisible to the naked eye.

This enigmatic pair orbits each other, separated by a mere 0.2 Astronomical Units (AU). This close proximity has led to some fascinating space phenomena. The black hole, believed to have a mass equivalent to 21.2 solar masses, has an effective radius of 44km. As a consequence of its immense gravity, no light can escape a black hole, leading to many strange space and time related phenomena.

The presence of Cygnus X-1 was first identified as a black hole by Paul Murdin and Louise Webster in 1971. Since then, the system has been the subject of numerous astronomical studies.

To locate HDE 226868, begin by centering up on Eta Cygni. From there, drift 8 arcminutes to the north of TYC2678-2291-1 and a fraction west. After finding mag. +7.3 HIP 98193, head 18 arcminutes east to find mag. +8.9 TYC2678-2291-1. Finally, drift another 8 arcminutes to the north and a fraction west to locate HDE 226868, the visible component of the Cygnus X-1 system.

The discovery of HDE 226868's companion black hole is attributed to the energetic and hot accretion disk that surrounds it. This disk, the source of X-rays that gave away the black hole's existence, is the result of HDE 226868's stellar wind removing material from the star, which ends up spiraling around the black hole.

If you're inspired to learn more about this fascinating cosmic duo, feel free to share your findings with us at contactus@our website. The guide for locating Cygnus X-1 was originally published in the October 2021 issue of our website.

In 2022, the star HDE 226868 was located in the constellation Cygnus, offering stargazers a unique opportunity to witness this celestial dance. As we continue to unravel the mysteries of the universe, who knows what other cosmic waltzes we might find?

Navigate the cosmos to discover Cygnus X-1, the elusive black hole, using our handy guide for identifying it in the night sky