RA 38.1772° · Dec 61.4560° · star
1 more point to reach Rare.
HD 15558 is an uncommon star. It sits in the constellation Cas, shines at apparent magnitude 7.91 and has spectral type O5e.
Its spectrum reads O5e — an O-type star — the hottest, rarest main class there is. Fewer than one star in a million is an O, and none of them lasts long.
Look for HD 15558 in the constellation Cas. At apparent magnitude 7.91, it is an easy target for binoculars.
Like any astronomical target, HD 15558 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 15558 scores 33 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 1 point would lift it into a rarer tier.
That score comes from 3 science badges — Star, Never sets (northern circumpolar) and Blazing O-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.