Page "Cygnus (constellation)" Paragraph 2

There are several other dimmer double and binary stars in Cygnus.

Mu Cygni is a binary star with an optical tertiary component.

The binary system has a period of 790 years and is 73 light-years from Earth.

The primary and secondary, both white stars, are of magnitude 4. 8 and 6. 2, respectively.

The unrelated tertiary component is of magnitude 6. 9.

Though the tertiary component is divisible in binoculars, the primary and secondary currently require a medium-sized amateur telescope to split, as they will through the year 2020.

The two stars will be closest between 2043 and 2050, when they will require a telescope with larger aperture to split.

Omicron Cygni is a contrasting double star similar to the brighter Albireo.

The components, 30 Cygni and 31 Cygni, are divisible in binoculars.

The primary, 31 Cygni, is an orange-hued star of magnitude 3. 8, 1400 light-years from Earth.

The secondary, 30 Cygni, is a blue-green hued star of magnitude 4. 8, 720 light-years from Earth.

31 Cygni itself is a binary star ; the tertiary component is a blue star of magnitude 7. 0.

Psi Cygni is a binary star divisible in small amateur telescopes, with two white components.

The primary is of magnitude 5. 0 and the secondary is of magnitude 7. 5.

61 Cygni is a binary star divisible in large binoculars or a small amateur telescope.

It is 11. 4 light-years from Earth and has a period of 650 years.

Both components are orange-hued dwarf ( main sequence ) stars ; the primary is of magnitude 5. 2 and the secondary is of magnitude 6. 1.

61 Cygni is significant because Friedrich Wilhelm Bessel determined its parallax in 1838, the first star to have a known parallax.

16 Cygni is a binary star 70 light-years from Earth.

Both components are white and of the 6th magnitude.