Struve 1850: A Wide Binary Star in Boötes

Posted byWayne McGrawPosted inDouble/Multiple StarsTags:, ,
Illustration of double star system

On spring and summer nights, the binary Struve 1850 shines down from the northern constellation of Boötes, the Herdsman. The two stars are wide apart in the sky, making them an easy target to find. The prolific 19th-century astronomer Friedrich Georg Wilhelm Struve cataloged the pair in 1823, and they represent several great doubles for amateur astronomers to track down in the Herdsman, including Delta Boötis, Izar, Iota, and many more.

Struve 1850 is located in the region indicated by the arrow. Credit: Stellarium

A Tale of Two A-Type Stars

Struve 1850 consists of two nearly identical stars, both classified as A1V spectral type stars. These are hot, white main-sequence stars significantly more massive and luminous than our Sun. With magnitudes of 7.1 and 7.6, and the generous separation between them, these stars are easy for backyard stargazers to enjoy with binoculars or small telescopes. As noted by Bob Argyle, this pair lies more than 800 light-years away from us in their serene cosmic dance.

My Observations

DateMay 12, 2023
Time10:52 P.M.
LocationSeattle, WA
Magnification169x
ScopeMeade 8″ SCT
Eyepiece12mm
SeeingAverage
TransparencyAverage
Sketch of Struve 1850 binary star in the constellation of Bootes. The drawing shows the two stars as they appear through an 8-inch SCT telescope under suburban skies using a 12mm eyepiece. The pair is also known as: STF 1850, HD 127067, SAO 83374, HIP 70786, HR 5414
Sketch of Struve 1850 on a late spring night

On a crisp May evening as the clock approaches 11 PM, I turn my telescope toward Struve 1850 high in the southeastern sky. After careful star-hopping through Boötes’ sparse star field, the distinctive pair swims into view.

Both stars appear remarkably similar, displaying a very subtle yellow tint against the black velvet of space. The companion star, slightly dimmer than its primary, mirrors its partner overall in this serene cosmic dance.

Key Stats

ConstellationBoötes
Best ViewingSpring
Visual Magnitude+7.1, +7.5
Separation25.29″
Position Angle262°
Distance from Earth873 ly
Milky Way LocationOrion Spur
My Viewing GradeB
DesignationsSTF 1850, HD 127067, SAO 83374, HIP 70786, HR 5414, 2014-00239-1, GC 19521

Sources and Notes

Stelle Doppie. (n.d.). [Entry for Struve 1850]. Retrieved from https://www.stelledoppie.it/index2.php?iddoppia=59980

Bob Argyle. (2023, May). Double Star of the Month: STF1850. The Webb Deep-Sky Society. Retrieved from https://www.webbdeepsky.com/double-stars/object?object=STF1850

Sketch by Wayne McGraw

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