RA 107.8484° · Dec -0.3019° · star
9 more points to reach Rare.
21 Mon is an uncommon variable star. It lies about 284.4 light-years from Earth, sits in the constellation Mon, shines at apparent magnitude 5.44 and has spectral type F2V.
Its spectrum reads F2V — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
Look for 21 Mon in the constellation Mon. At apparent magnitude 5.44, it can be glimpsed with the unaided eye under dark skies.
Like any astronomical target, 21 Mon 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 Mon scores 25 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 9 points would lift it into a rarer tier.
That score comes from 6 science badges — Variable star, Naked-eye visible, Yellow-white F-type star, Main-sequence star, Gently variable and A named variable 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.