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Uncommon star 25 EP

HD 180420

RA 289.4823° · Dec -34.5195° · star

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Score breakdown

· 5 badges
25 pts · Uncommon
Uncommon 34 pts → Rare
  • Toward the galactic centre +8
  • Giant star +6
  • White A-type star +5
  • Star +3
  • On the zodiac +3
Total score 25

9 more points to reach Rare.

Badges

  • Star · +3
  • Toward the galactic centre · +8
  • On the zodiac · +3
  • White A-type star · +5
  • Giant star · +6

Trivia

What it actually is

  • Spectral class. Its spectrum reads A7III — 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.
  • Where it is in life. It is a giant. It has already exhausted its core hydrogen and swollen up enormously in response.

Sense of scale

  • In perspective. Far away by human standards, yet still a local address inside the Milky Way's spiral arms.

Find it in the sky

  • How to spot it. At magnitude 8.3 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Sagittarius.
  • Southern sky. It rides the southern half of the sky — an easier target the further south you are.
  • Best time of year. It stands highest in the middle of the night around July — that's when to go looking.

Could we get there?

  • Verdict. Hopelessly far for any craft humanity can build today.

Getting there

  • Aboard Voyager 1. ≈ 11.1 million years at Voyager 1's speed (17 km/s).

Properties

absmag
1.869
bv
0.339
constellation
Sgr
dist ly
633.3128
luminosity
15.574
mag
8.31
name
HD 180420
spect
A7III

About HD 180420

HD 180420 is an uncommon star. It lies about 633.3 light-years from Earth, sits in the constellation Sgr, shines at apparent magnitude 8.31 and has spectral type A7III.

Its spectrum reads A7III — 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.

How to see it

Look for HD 180420 in the constellation Sgr. At apparent magnitude 8.31, it is an easy target for binoculars.

Like any astronomical target, HD 180420 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.

Why HD 180420 is an uncommon star

HD 180420 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 5 science badges — Star, Toward the galactic centre, On the zodiac, White A-type star and Giant 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.