RA 178.8687° · Dec 54.7794° · star
3 more points to reach Common.
HD 103540 is a trash star. It lies about 652.3 light-years from Earth, sits in the constellation UMa, shines at apparent magnitude 8.43 and has spectral type A3.
Its spectrum reads A3 — 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 103540 in the constellation UMa. At apparent magnitude 8.43, it is an easy target for binoculars.
Like any astronomical target, HD 103540 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 103540 scores 12 points on Spacedle's rarity scale, which places it in the trash tier. Another 3 points would lift it into a rarer tier.
That score comes from 3 science badges — Star, Never sets (northern circumpolar) and White A-type star — 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.