61 Cygni / ˈsɪɡni / is a binary star system in the constellation Cygnus, consisting of a pair of K-type dwarf stars that orbit each other in a period of about 659 years. Of apparent magnitude 5.20 and 6.05, respectively, they can be seen with binoculars in city skies or with the naked eye in rural areas without light pollution.

天鹅座61 （英语：61 Cygni），有时也被称为贝塞尔星（Bessel's Star）或皮亚齐飞行之星（Piazzi's Flying Star），中国传统名称天津增廿九，是一个位于天鹅座的双星系统，由一对K型橙矮星所组成，彼此互相以659年的周期运转，形成一个目视双星系统。

2023年8月11日 · 61 Cygni is a double star in the constellation Cygnus the Swan. It’s not a standout in brightness. Why go to the trouble of finding it? Stars are individuals, and there’s something interesting...

61 Cygni is a variable and multiple main-sequence star of spectral class K7 in the constellation of Cygnus. 61 Cygni visual magnitude is 6.03. Because of its faintness, 61 Cygni is visible to the naked eye only from locations with very dark skies, while it is not visible at all from skies affected by light pollution.

61 Cygni, first star whose distance from Earth was measured. German astronomer Friedrich Wilhelm Bessel obtained a value of 10.3 light-years in 1838; the European Space Agency satellite Hipparcos made much more accurate distance measurements than ground-based telescopes had accomplished and

61 Cygni is a binary star system in the constellation Cygnus. The system consists of a pair of K-type dwarf stars that orbit each other in a period of about 659 years. The stars have an apparent magnitude of 5.20 and 6.05, respectively.

2015年6月3日 · Our second featured star, 61 Cygni, is one of summer's best and brightest double stars — a gorgeous pair of orange-red dwarfs (magnitudes 5.2 and 6.0) located 11.4 light-years away in Cygnus. 61 Cygni shines with a combined magnitude of 6.2 and forms the fourth corner of a parallelogram made with Deneb, Gamma, and Epsilon Cygni.

61 Cygni was the first star system (other than the Sun) to have its distance to Earth successfully calculated by Friedrich Wilhelm Bessel (1784-1846) using trigonometric parallax and the diameter of the Earth's orbit around the Sun in 1838. Smaller and dimmer than Sol, the stars are barely visible with the naked eye.

61 Cygni / ˈsɪɡni / is a binary star system in the constellation Cygnus, consisting of a pair of K-type dwarf stars that orbit each other in a period of about 659 years. Of apparent magnitude 5.20 and 6.05, respectively, they can be seen with binoculars in city skies or with the naked eye in rural areas without light pollution.

61 Cygni lies to the southeast of Deneb. Look for a triangle of stars of similar brightness. 61 Cyg is the westernmost. North is up and east is left. In 2009 these stars are 31.3" apart, making them easy in any scope. The cool surface temperatures give them a ruddy orange hue that really makes them stand out in the field.