61 Cygni (Piazzi's Flying Star)

Magnitude A / B / C
Separation A-BC/ AC
Position angle A-BC / AC
Spectral class A / B / C
Colour A / B / C
: Cygnus
: 21:06:51 / +38.44
: 5.3 / 6.1
: 31.1"
: 151°
: K5V / K7V
: yellow / yellow-orange
Detail sketch:
Date / Time
Observing Location
Seeing / Transparency
Magnification / Field of View '
: 22/10/08 / 21:30
: Landgraaf
: 3/4
: Orion Optics UK 300 mm
: 17 mm Nagler type 4
: 94 / 52
61 Cygni

Observing Report

In the 35mm 61 Cygni is easily split, and looks already beautiful, two yellow-orange eyes set against a black velvet sky (almost in the zenith during observation). A very easy object to locate and observe. The magnitude of both components seems to be almost equal at first, but when you observe a bit more carefully, you will notice that the A-component is slightly brighter than the B-component. The optimum magnification is 94x, which is achieved by using the 17mm Nagler. The surroundings are not very spectacular. There are no prominent field stars visible. There is however one star that can be seen perpendicular to the 61 Cygni double. Together they form a small triangle. To the north-west of 61 Cygni I see another small triangle of stars, one star a bit brighter, the other two very dim.

Now we come to the colour. When you read a few of the historic observing reports, you quickly notice that “seeing colour” is something that varies greatly. Every observer has its own perception of colour. Webb saw 61 Cygni as “yellow or gold”, while Smyth writes “both yellow, but the small one is of the deepest tint”. Burnham sees them both as “fine orange tint”, while Haas describes them both as “amber-yellow”. To me, the A-component looks more or less yellowish, the B-component seems to have an orange tint to it.


61 Cygni is a visual binary with a period of 659 years (Haas). It is only 11.4 lightyears away from us. It is the fourth nearest star to the earth, that can be seen with the naked-eye (under dark skies). Only Sirius, Alpha Centauri and Epsilon Eridanus are closer. The double is composed of two cool dwarfstars. The brighter A-component, a K5 star, has a temperature of 4450 K. The B-component, a K7 star, is a bit cooler, 4120 K. 61 Cygni has a large proper motion, about 5 arcseconds per year. This was first noticed by Piazzi in 1792. That's why he called it “The Flying Star”.