RA 277.0260° · Dec -20.8111° · star
2 more points to reach Rare.
HD 169991 is an uncommon star. It sits in the constellation Sgr, shines at apparent magnitude 9.84 and has spectral type B8/B9II/III.
Its spectrum reads B8/B9II/III — a blue-white B-type star, with a surface tens of thousands of degrees hot and a life measured in tens of millions of years.
Look for HD 169991 in the constellation Sgr. At apparent magnitude 9.84, a small backyard telescope will bring it into view.
Like any astronomical target, HD 169991 is best seen from a dark site away from city lights, and when it is above the horizon depends on your latitude and the time of year. The visibility panel above works out tonight's viewing window for your saved location.
HD 169991 scores 32 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 2 points would lift it into a rarer tier.
That score comes from 5 science badges — Star, Toward the galactic centre, On the zodiac, Hot blue B-type star and Bright giant — each earned for a real, measurable property of the object. Rarity on Spacedle is never random: the more remarkable an object's astrophysics, the more badges it collects, the higher it scores, and the rarer it ranks.