Obects & Observing Tips:
Nebulae
[NASA photo, APOD]
You are here: Haggart Observatory >> Favorite Objects >> Nebulae
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Obects & Observing Tips: Nebulae |
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You are here: Haggart Observatory >> Favorite Objects >> Nebulae |
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Diffuse (star-forming) Nebulae:
These are areas of hot, glowing gas in which new stars are condensing; they
are very dramatic objects, though the stunning colors seen in photographs are
not visible to the human eye, even through a telescope. (Our eyes "refresh"
too frequently to pick up the colors, except for possibly a bit of pinkish glow
in large amateur telescopes. Computer imaging and photographic plates can collect
light over long periods.) Because they are so young - only a few million years
old, with ongoing star formation - they still contain extremely massive, bright
but short-lived, O and B type stars.
( Check out the SEDS explanation of diffuse
nebula.)
Observing Diffuse Nebulae:
Best Bets:
There are only a few of these fine objects available. (Links are
to the SEDS website description.)
| Nebula | Constellation | Availability by month | Mag. | Dist. (ly) |
Diam (ly) |
|||||||||||
| J | F | M | A | M | J | J | A | S | O | N | D | |||||
| M8: Lagoon |
Sagittarius
|
- | - | - | - | - | - | X | X | X | - | - | - |
6
|
5,200
|
136
|
| M17: Omega, Swan |
Sagittarius
|
- | - | - | - | - | - | X | X | X | - | - | - |
6
|
5,000
|
75
|
| M20: Trifid |
Sagittarius
|
- | - | - | - | - | - | X | X | X | - | - | - |
8
|
5,200
|
44
|
| M42 / M43: Orion | Orion | X | X | X | - | - | - | - | - | - | - | X | X |
4
|
1,600
|
30
|
| M78 | Orion | X | X | X | - | - | - | - | - | - | - | X | X |
8.3
|
1,600
|
4
|
"Planetary" (dying star)
Nebulae:
star in final stages of life cycle has "blown off" much of its surface
layers, or "atmosphere" into an expanding ring or dumb-bell shaped
cloud
the remnant of the central star is a "white dwarf"
binoculars: dim, hard to spot with any light pollution
telescopes: spot with low power, use high power to view (24mm or less)
| Constellation | J | F | M | A | M | J | J | A | S | O | N | D | Mag | Dist (ly) | Diam (ly) | Age (yrs) | |
| M27: Dumbbell | Vulpecula | - | - | - | - | - | X | X | X | X | X | X | - |
7.4
|
1,250
|
2
|
?
|
| M57: Ring | Lyra | - | - | - | - | X | X | X | X | X | X | X | - |
8.8
|
2,300
|
2.4
|
8,000
|
| M76: Little Dumbbell | Perseus | X | X | X | - | - | - | - | - | - | X | X | X |
10.1
|
3,400
|
2.6
|
?
|
| M97: Owl | Ursa Major | - | X | X | X | X | X | X | X | X | - | - | - |
9.9
|
2,600
|
?
|
6,000
|
[It is apparently very hard to determine distances to planetary nebulae, and diameter and age estimates depend on the distance; different authors report wildly varying distances. SEDS gives age estimates on the Dumbbell of 4,000 years from one study and 48,000 years on another]
| Constellation | J | F | M | A | M | J | J | A | S | O | N | D | Mag | Dist (ly) | |
| M1: Crab Nebula |
Taurus
|
X | X | X | - | - | - | - | - | - | - | X | X |
8.4
|
6,300
|
The Crab Nebula is the remnant of a supernova that appeared in 1054 AD.
Data sources:
SEDS "Diffuse Nebulae" website: www.seds.org/messier/diffuse.html
(note on ages: if several given, I've used the one attributed to Sky Catalog
2000)
Sky and Telescope Messier Card, 1997
Watson, Brent. Finder Charts of the Messier Objects, 1993
(Monthly availability determined from star charts in Rey, The Stars: a New Way to See Them and at Heavens-Above.com)