RA 172.4893° · Dec 46.2580° · star
5 more points to reach Uncommon.
HD 99900 is a common star. It lies about 516.9 light-years from Earth, sits in the constellation UMa, shines at apparent magnitude 8.58 and has spectral type A7IV.
Its spectrum reads A7IV — an A-type star: white-hot, typically about twice the Sun's mass, and the class most of the sky's famous bright stars belong to.
Look for HD 99900 in the constellation UMa. At apparent magnitude 8.58, it is an easy target for binoculars.
Like any astronomical target, HD 99900 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 99900 scores 17 points on Spacedle's rarity scale, which places it in the common tier. Another 5 points would lift it into a rarer tier.
That score comes from 4 science badges — Star, Never sets (northern circumpolar), White A-type star and Subgiant (leaving the main sequence) — 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.