RA 252.8539° · Dec 1.2159° · star
4 more points to reach Uncommon.
21 Oph is a common star. It lies about 378.8 light-years from Earth, sits in the constellation Oph, shines at apparent magnitude 5.51 and has spectral type A2Vs.
Its spectrum reads A2Vs — 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 21 Oph in the constellation Oph. At apparent magnitude 5.51, it can be glimpsed with the unaided eye under dark skies.
Like any astronomical target, 21 Oph 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.
21 Oph scores 18 points on Spacedle's rarity scale, which places it in the common tier. Another 4 points would lift it into a rarer tier.
That score comes from 4 science badges — Star, Naked-eye visible, White A-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.