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Common star 15 EP

HD 188504

RA 298.5961° · Dec 30.0253° · star

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Score breakdown

· 3 badges
15 pts · Common
Common 22 pts → Uncommon
  • Hot blue B-type star +6
  • Giant star +6
  • Star +3
Total score 15

7 more points to reach Uncommon.

Badges

  • Star · +3
  • Hot blue B-type star · +6
  • Giant star · +6

Trivia

Hard to believe

  • True brightness. It pours out about 4.3 million times as much light as the Sun. It only looks ordinary because it is so far away.

What it actually is

  • Spectral class. Its spectrum reads B7III — a blue-white B-type star, with a surface tens of thousands of degrees hot and a life measured in tens of millions of years.
  • Where it is in life. It is a giant. It has already exhausted its core hydrogen and swollen up enormously in response.

Find it in the sky

  • How to spot it. At magnitude 8.2 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 July — that's when to go looking.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out brilliant white (B−V 0.1) — hotter and whiter than the Sun, the colour of Sirius or Vega.
  • Why no green stars. No star ever looks green: a surface hot enough to peak in green also floods out plenty of red and blue, and your eye blends the mixture back to white.

Properties

absmag
-11.76
bv
0.109
constellation
Cyg
luminosity
4405548.6351
mag
8.24
name
HD 188504
spect
B7III

Nearby objects

About HD 188504

HD 188504 is a common star. It sits in the constellation Cyg, shines at apparent magnitude 8.24 and has spectral type B7III.

Its spectrum reads B7III — a blue-white B-type star, with a surface tens of thousands of degrees hot and a life measured in tens of millions of years.

How to see it

Look for HD 188504 in the constellation Cyg. At apparent magnitude 8.24, it is an easy target for binoculars.

Like any astronomical target, HD 188504 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 188504 is a common star

HD 188504 scores 15 points on Spacedle's rarity scale, which places it in the common tier. Another 7 points would lift it into a rarer tier.

That score comes from 3 science badges — Star, Hot blue B-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.