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Uncommon star 24 EP

HD 203840

RA 320.8371° · Dec 44.5183° · star

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Score breakdown

· 4 badges
24 pts · Uncommon
Uncommon 34 pts → Rare
  • Intrinsically luminous (Mv < −2) +10
  • Distant (over 1,000 light-years) +6
  • White A-type star +5
  • Star +3
Total score 24

10 more points to reach Rare.

Badges

  • Star · +3
  • Distant (over 1,000 light-years) · +6
  • White A-type star · +5
  • Intrinsically luminous (Mv < −2) · +10

Trivia

What it actually is

  • Spectral class. Its spectrum reads A0 — 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.

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 7.2 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Cygnus.
  • Northern sky. It rides the northern half of the sky — an easier target the further north you are.
  • Best time of year. It stands highest in the middle of the night around August — that's when to go looking.

Could we get there?

  • Verdict. Impossible with our current technology — and the next millennium of it.

Getting there

  • Aboard Voyager 1. ≈ 40.1 million years at Voyager 1's speed (17 km/s).
  • Fastest probe ever. ≈ 3.6 million years even at the Parker Solar Probe's 192 km/s.

Properties

absmag
-2.053
bv
0.184
constellation
Cyg
dist ly
2280.8112
luminosity
577.0321
mag
7.17
name
HD 203840
spect
A0

About HD 203840

HD 203840 is an uncommon star. It lies about 2,280.8 light-years from Earth, sits in the constellation Cyg, shines at apparent magnitude 7.17 and has spectral type A0.

Its spectrum reads A0 — 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 203840 in the constellation Cyg. At apparent magnitude 7.17, it is an easy target for binoculars.

Like any astronomical target, HD 203840 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 203840 is an uncommon star

HD 203840 scores 24 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 10 points would lift it into a rarer tier.

That score comes from 4 science badges — Star, Distant (over 1,000 light-years), White A-type star and Intrinsically luminous (Mv < −2) — 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.