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NGC 1976
Orion Nebula
Messier 42, Bernes 117
RA 05:35:24
Dec -05°
27.0'
Bright nebula |
This nebula is one of the most dramatic and
best known nebulae in the sky. It lies in the Sword of Orion, surrounding the
multiple star Theta Orionis, which illuminates it. M42 is the nearest emission
nebula to Earth, lying about 500 parsecs away. To the naked eye it appears as a
luminous patch, about the size of the Moon. As seen through a telescope, its
green tint is obvious to most, while some have even glimpsed red and pink areas.
William Herschel observed it in 1784 with his
newly completed 18.7-inch f/13 speculum telescope. He wrote of "the
beautiful Nebula of Orion. Its extent is much above one degree; the eastern
branch passes between two very small stars, and runs on till it meets a very
bright one. Close to the four small stars, which can have no connection with the
nebula, is a total blackness; and within the open part, towards the north-east,
is a distinct small faint nebula, of an extended shape, at a distance from the
border of the great one, to which it runs in a parallel direction, resembling
the shoals that are seen near the coasts of some islands." In the Appendix
to the 1912 'Scientific Papers of Sir William Herschel' this object is described
as "1774, March 1, 20 feet telescope, observed the Lucid Spot in Orion's
sword belt; but the air not being very clear, it appeared not distinct. 1774,
March 4, saw the lucid spot in Orion's sword thro' a 5.5 foot reflector; its
shape was not as Dr Smith has delineated in his Optics; tho' something
resembling it, being nearly as follows [Plate III. fig. 37]. From this we may
infer that there are undoubtedly chnages among the fixt stars, and perhaps from
a careful observation of this spot something might be concluded concerning the
nature of it. . . . 1780, February 19. Exactly as described on October 7, 1779 .
. . 1780, November 24. The Nebula in Orion is very fine indeed. I perceive not
the least alteration . . . 1783, January 31, Theta Orionis. The Nebula is quite
different from what it was last year. The 9th star very strong. 1783, September
20, the Neb. in Orion has evidently changed its shape since I saw it last. The
star under the nebula is nebulous, 20ft, 200 power. 1783, September 28,
Surprising changes in the Nebula Orionis. 1783, November 3. The Nebula in Orion
is beautiful, and I see several circumstances which I never observed with other
instruments, viz. just close to the four stars it is totally black for a very
short space, a few seconds. Below, in the open black part is a small distinct
nebula of an extended shape [This is III.1, an appendage to Messier 43]. The
eastern branch of the great nebula extends very far; it passes between two very
small stars and runs on so far as to meet a pretty bright star. The nebulous
star below the nebula is not equally surrounded, but most towards the south; on
the north of this lesser nebula it is joined by one still fainter, which makes a
rectangular corner by its meeting the small nebula . . . 1784, October 16 .. My
small neb. is just under the south following corner of the great one. The 43d is
not a nebulous star, the star not being at all in the centre of it; my little
one makes a part of it. It is altogether the most wonderful object in the
heavens . . . 1810, February 4, Review. 10 feet., The nebulosity is entirely of
the milky kind and extends a great way. The 43d is not a nebulous star, but a
star which happends to be situated in a place where some of the milky nebulosity
of the great nebula happens to be. The star is not central, nor is there any
condensation towards the star.
John Herschel, observing with his 18-inch
reflector in the mid-1800's, likened it to a "surface strewn with flocks of
wool - or like the breaking up of a mackerel sky."
IAAC contribution, Todd Gross (16-inch
Newtonian): “This is by far the best astronomical object in this scope. In
fact, the view is so good, it far exceeds the beauty seen in photographs. The
nebula is a huge emission nebula with filamentary arms, clouds of gas, and dark
rifts. Separated by M43 by a broad, glow-free area. I will not try to describe
the nebula in detail at this time. Here is an overview though. In my slightly
light polluted skies, the 19mm Panoptic at 98x brought out the best wide view.
At first glance, the entire complex looked strong, almost electric (radiant)
blue-green ( a bit closer to green ). This is the most colorful object I have
ever seen bar some doubles and perhaps Jupiter. Color was best maintained at
98x, but was also seen clearly at 210x... and through the binoviewer, also
approximately working at 210x. On closer inspection, I could "derive"
that the arms, particularly the more well defined arm, using a UHC filter.. was
actually reddish. This was more of a grey, but the mere subtraction of green
from this area, does give one the impression that with more light throughput,
red would be more clearly seen. Color was seen both with and w/o the UHC filter,
which mainly enhanced the outer regions of the nebula, nearly doubling it's
nebulosity. In the bright center area, (rectangular) surrounding the Trapezium,
that is so often seen "burnt-in" to photographs, there were included
intricate lacy threads of gas, and a nearly complete "canal" or dark
lane cutting almost all the way through it, (bisecting it , but offset) opposite
from M43, and opp. from the dark wedge that pokes into it. This was not at all
like any photos, much better resolution. The outer arms were lacy, and delicate,
very clearly seen, similar to photos,but nearly colorless the further out you
go. The Trapezium stars, at the core of the brightest part of the nebula were a
bit bloated, due to seeing . 4-5 stars were clearly noted. More on the Trapezium
stars (6) was reported on in a separate observation report. M43 looks like it is
included in M42, a roundish piece cut off from the main body.”
Donald J. Ware:”The Great Nebula. One of
the finest sights in the sky, this nebula is easily visible to the naked eye as
the”fuzzy" star in the middle of Orion's sword. It appears distinctly
nebulous in binoculars or finder scopes, and shows an amazing amount of detail
through the telescope. It is fully a degree in extent, with a wealth of fine
curling wisps of nebulosity curving out from the brightest region surrounding
the four relatively bright stars known as the Trapezium. On good nights with low
power, I have even been able to see colors in this object. The region around the
Trapezium appears as a cold steel blue color, wile the wispy regions further
away can appear as a soft ruddy pink. Slightly separated from the main
nebulosity, is M-43. This nebula is seen as a comma shaped cloud surrounding an
eighth magnitude star just north of the Great Nebula. The more time you spend in
this area, the more fine detail can be seen.”
Le Forbes (Stoke, St. Mary Bourne, Hampshire)
observing from Puimichel, France, writes in the The Webb Society Nebulae and
Clusters Section Report No. 11, January 1993: "Extremely detailed nebula,
with many wisps and filaments spreading out of the field. Pink tinge visible in
M43. (42-inch, x185/x310)"
Tom Lorenzin, in the electronic version of "1000+
The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: “4M;
>1 degree extent! the "ORION NEBULA"; illuminated by Theta ORI;
defies description! find it-- revel in the wisps, filaments and colors-- and
come up with your own!.”
Steve Gottlieb: 17.5-inch: best emission
nebula in northern sky, fantastic view under all conditions, bright colored
wings sweep to the E and S. The remarkable structure is difficult to describe
but includes bays, filaments, knots, nebulous stars and a huge outer loop.
Definite colors are visible including pale greens and pinks. Highlighted by the
Trapzezium which contains six stars. The bright portion surrounding Theta has an
"electric" appearance with dark streaks and a dark wedge = "fish's
mouth" intrudes on the NE side. Using an Hß filter, the nebulosity
significantly dims in general but there is one outer wing or loop on the W side
(oriented N-S) which obviously increases in contrast with the filter!
Steve Coe, using a 13” f/5.6, notes: “Extremely
Bright, extremely large, irregular shape, very much brighter in the middle at
100X in the 13". The Great Orion Nebula is certainly a showpiece and it
probably is the most observed deep sky object in the Winter sky, it deserves
that position of honor. On a night I rated 9/10 for transparency at a very dark
site in the Arizona desert the center of the Sword of Orion is fuzzy to the
naked eye. In my 11X80 finder the "batwings" feature of the nebula is
obvious, with the western side brighter. Going to the 13" at 100X, the
nebulosity is larger than the 30' field of view. All 6 six stars in the
Trapezium section are seen and a backround of very faint stars embedded in the
nebula are at the limit of averted vision. The area around the Trapezium in
very, very mottled, like storm clouds. The dark marking called the "fish
mouth" appears three dimensional. The dark area is obviously in front of
the nebulosity. The dark lane extends beyond the nebula to the NE. Raising the
power to 220X will hold 10 of the faint stars in the nebula steady. The central
region around the Trapezium has "rays" of nebulosity that extend into
the darker region to the south. The Trapezium stars are contained within a "hole"
in the nebula, it appears that these stars lit off and blew away the material
nearby. At all powers, the nebula is a pale lime green and has pink fringes
where the nebulosity is brightest. Overall a spectacular object that no
photograph or drawing can truly capture. 13" Sentinel 8/10 38mm Entire
sword region just fits, very bright, very, very large, much brighter middle, 57
stars involved incl 4 in Trapezium. Grey-green color and entire circle of Orion
Neb. included. 100X a great view, excellent contrast, bright curved wings lead
away from Trapezium to the north and south, Fishmouth takes a bite in from the
East. WOW!! 6" f/6 Sun Valley 22mm panoptic very bright, very large,
irregular figure, much, much brighter middle, many stars involved. A fabulous
view of the entire Sword area. Adding the UHC filter makes for a very contrasty
view of this famous region.”
David Neilson (Oakland, California, USA),
writes in the The Webb Society Nebulae and Clusters Section Report No. 10, July
1992: "Much detail seen near the Trapezium and opposite dark gulf; very
convoluted and turbulent appearance. Bluish colour very obvious, as also are the
outlying arms, which show a reddish tint. (8-inch)."
Alan Shaffer, using a 10-inch
Schmidt-Cassegrain reflector, notes: “Can't resist a view. The seeing in
Palos Verdes was great. This object jumped out of the night sky. At 104X, the
object more than filled the field. Pale green in color. Noticed that one of the
nebula arms extended very far. The dark central region gave great contrast to
the beautiful glow. Always a grand view!!”
See also "Visual Astronomy of the Deep
Sky" by Roger N. Clark (1990, Sky Publishing Corporation) page 98, and "The
Visual Orion Nebula" in Astronomical Scrapbook, Sky & Telescope,
November 1975, p299.
15.5-inch f/9 Newtonian: For
the most part, astro-photos are a bane to deepsky observers. Many people get
turned off deepsky because their scopes don’t show the same breathtaking
views depicted on long-exposure photos. I too was disillusioned with the Orion
Nebula when I first saw it with my 2-inch refractor -- I was naively expecting
to see the writhing gas streamers, etc, etc. A few years later, after
nevertheless continuing to scan the sky with the 2-inch, I had the great fortune
of getting access to a 15.5-inch f/9 equatorially mounted Newtonian. On that
first clear, crisp night, I turned the 15.5-inch on M42. I was observing with a
friend of mine, using the lowest power eyepiece we had (110x). He located the
nebula, or so he thought. What he had actually found was the fainter M43 nearby.
But we were astounded! This was amazing, and we spent a good while studying the
nebula. And then, I nudged the old Newtonian a fraction, and M42 drifted
silently into view. Wow, what an entrance! There were my writhing gas streamers!
The trapezium was easily visible, and the surrounding nebulosity awesome.
Equally prominent was the darkening leading to the Trapezium. Most of all, there
was a long streamer sweeping away from the main complex. Now I could go back to
my earlier 2-inch observations and sketches, and identify the bits I had seen -
the trapezium, the winged nebulosity, and the dark nebula. [AS] |
