RA 345.5515° · Dec 57.1939° · star
15 more points to reach Epic.
HD 240165 is a rare star. It sits in the constellation Cas, shines at apparent magnitude 10.12 and has spectral type O9.5V.
Its spectrum reads O9.5V — 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 240165 in the constellation Cas. At apparent magnitude 10.12, a small backyard telescope will bring it into view.
Like any astronomical target, HD 240165 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 240165 scores 35 points on Spacedle's rarity scale, which places it in the rare tier. Another 15 points would lift it into a rarer tier.
That score comes from 4 science badges — Star, Never sets (northern circumpolar), Blazing O-type star and Main-sequence 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.