About Box Nebula
Box Nebula is a rare nebula. It sits in the constellation Oph and shines at apparent magnitude 11.5.
A planetary nebula: the shed outer atmosphere of a dying Sun-like star, lit from within by the naked stellar core left behind.
Rare nebula 38 EP
Box Nebula
RA 258.5179° · Dec -12.9106° · openngc
Score breakdown
· 4 badgesRare 50 pts → Epic
- Planetary nebula (a dying star's shell) +12
- Coming towards us +10
- Nebula +8
- Has a proper name +8
Total score 38
12 more points to reach Epic.
Badges
- Nebula · +8
- Has a proper name · +8
- Planetary nebula (a dying star's shell) · +12
- Coming towards us · +10
Trivia
What it actually is
- What it actually is. A planetary nebula: the shed outer atmosphere of a dying Sun-like star, lit from within by the naked stellar core left behind.
Find it in the sky
- How to spot it. At magnitude 11.5 you'll want a small backyard telescope, over in Ophiuchus.
- 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 June — that's when to go looking.
Its true colour
- Its true colour. Its teal-green comes from doubly-ionised oxygen at 501 nanometres, and its red from hydrogen at 656 — colours no ordinary object on Earth produces.
What's in a name
- A misleading name. 'Planetary nebula' is a 240-year-old mistake. William Herschel coined it in the 1780s because these round greenish discs resembled the planet Uranus he had just discovered. There are no planets involved whatsoever.
- Named. Notable enough to have earned a proper name, not just a catalogue number.
How we came to know it
- The New General Catalogue. Its NGC number comes from J. L. E. Dreyer's 1888 catalogue, itself built on decades of sky sweeps by William Herschel and his sister Caroline.
Properties
- constellation
- Oph
- dso type
- PN
- mag
- 11.5
- name
- Box Nebula
- named
- yes
- radial velocity kms
- -40
- size arcmin
- 0.26
How to see it
Look for Box Nebula in the constellation Oph. At apparent magnitude 11.5, a small backyard telescope will bring it into view.
Like any astronomical target, Box Nebula 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 Box Nebula is a rare nebula
Box Nebula scores 38 points on Spacedle's rarity scale, which places it in the rare tier. Another 12 points would lift it into a rarer tier.
That score comes from 4 science badges — Nebula, Has a proper name, Planetary nebula (a dying star's shell) and Coming towards us — 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.