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Wed, 26 Apr 2017 02:16:07 GMTNGC 1977 The Running Man Nebula
Thu, 02 Nov 2006 20:45:17 GMT
Right Ascension: 5 : 35.5 (hours : minutes)
Declination: -04 : 52 (degrees : minutes)
Apparent Diameter: 20. (arc minutes)
Located in the Constellation Orion a bright nebula.]]>Astrophotographyhttp://ironwoodobservatory.com/gallery/details.php?image_id=32IC 434 Horsehead Nebula
Thu, 02 Nov 2006 20:43:35 GMT
Right Ascension 05 : 40.9 (h:m)
Declination -02 : 28 (deg:m)
Distance 1.6 (kly
Apparent Dimension 6x4 (arc min)
E. Pickering detected IC 434 photographically in 1889, the Horsehead can be detected on a photo made on January 25, 1900 by Isaac Roberts (Roberts 1902). E.E. Barnard recognized the object in the 1910s.
The first published description of the Horsehead Nebula was given in Barnard (1913), and it was first cataloged by Barnard (1919).
The remarkable Horsehead is a dark globule of dust and non-luminous gas, obscuring the light coming from behind, especially the moderately bright nebula IC 434. It is the most remarkable feature of an interesting region of diffuse nebulae, which belongs to a huge cloud of gas and dust situated 1,600 light years away in the direction of constellation Orion. The bright reflection nebula in the lower left is NGC 2023.]]>Astrophotographyhttp://ironwoodobservatory.com/gallery/details.php?image_id=31Diffuse Nebula M78 (NGC 2068), a reflection nebula, in Orion
Thu, 02 Nov 2006 20:42:15 GMT
Right Ascension 05 : 46.7 (h:m)
Declination +00 : 03 (deg:m)
Distance 1.6 (kly)
Visual Brightness 8.3 (mag)
Apparent Dimension 8x6 (arc min)
Discovered 1780 by Pierre Méchain.
M78 is the brightest diffuse reflection nebula in the sky. Discovered by Pierre Méchain in early 1780, Charles Messier added it to his catalog on December 17, 1780. It belongs to the Orion complex, a large cloud of gas and dust centered on the Orion Nebula M42/M43, and is about 1,600 light years distant. It is the brightest portion of a vast dust cloud which includes NGC 2071 (northeast, lower right in our image), NGC 2067 (close northwest), and very faint NGC 2064 (southwest), all visible in our image. Together with some other nebulae, including NGC 2024 (Orion B) near Zeta Orionis (sometimes called the Flame Nebula), all these nebulae are associated with the molecular cloud LDN 1630 (from Lynds' Catalogue of Dark Nebula), a part of the Orion complex.
As a reflection nebula, M78 is a cloud of interstellar dust which shines in the reflected and scattered light of bright blue (early B-type) stars, among them the brightest, HD 38563A, and second-brightest HDE 38563B, both of about 10th visual apparent magnitude. The nature of M78 as a reflection nebula was discovered by Vesto M. Slipher of Lowell Observatory in 1919 (Slipher 1919). At its distance, M78 measures almost 4 light years in extension.
The image in this webpage was obtained by Evered Kreimer with a 12.5-inch Newtonian from Arizona in the mid-1960s. This image acquired some late fame in February 2004, when J.W. McNeil's supposedly "newly" discovered nebula was discovered in it by a considerable number of attentive readers of these webpages.
In and near this nebula, 45 low mass stars with hydrogene emission lines, irregular variables similar to the star T Tauri, were detected. Stars of this type are main sequence stars which vary in brightness (by about 3 magnitudes) and spectral type (which is about F or G, and similar to the chromosphere of our sun), are 4 to 5 times brighter than their spectral type would suggest, and associated with nebulosity which may be bright or dark. Probably these are very young stars which are still in their formation process.
Infrared investigations have given a clearer image of the cluster of young stars which have formed in this nebula. From 2.2-micron investigations of the Molecular Cloud associated with M78, LDN 1630 (Orion B), performed with Kitt Peak National Observatory's 1.3-m IR telescope Lada et.al. (1991) concluded that much of the young, embedded star formation is occurring in clusters, including the formation of lower mass stars. After this paper, Archinal and Hynes (2003) call the open star cluster in M78 "[LDEG91] 3."
A large number of dramatic outflow sources are found in the region of M78; these so-called Herbig-Haro objects are presumably jets of matter ejected from young stars embedded in the nebulous matter of M78 where they have just formed. The discoveries by Zhao et al. (1999) brought the number of known Herbig-Haro objects in M78 to 17. A gorgeous IR image of M78 and the whole region was created by S. Van Dyk of IPAC with the 2MASS IR Telescope; these data provide an even deeper insight into the star formation process in M78.
M78 is not difficult to locate from Zeta Orionis, also named Alnitak, the easternmost star of Orion's Belt; M78 is situated about 2 degrees north and 1 1/2 degrees east of this star; a chain of 3 stars of mag 5..6, northward from Zeta, may help locating it. Alternatively, it is found roughly 1/2 deg North and 3 3/4 deg East of Delta Orionis, the NW most belt star.
Visually, M78 resembles a faint comet. It is just visible in binoculars under good conditions, as a very dim patch. Small telescopes already show it remarkably bright, and reveal the two illuminating stars, lying North preceding (NW) and South following (SE) like a double nucleus in the compact "comet head" part of M78; suggestions of a short and broad "tail" appear to reach to the South preceding (SW) end. The other nebulae in this field require a very dark sky and are much more difficult to see than M78; under very good conditions, a 4-inch can reveal NGC 2071, and suggestions of haze around M78. Stars are fewer to the west, an indication that in this region dark nebulae seem to obscure the stellar background. About 1 3/4 deg East of M78, open cluster NGC 2112 is found; this cluster is of about 9th mag and 11' in diameter, lies behind M78 at a distance of about 2800 light-years, and is much older: Estimated at about 2 billion years. (Source SEDS)]]>Astrophotographyhttp://ironwoodobservatory.com/gallery/details.php?image_id=30M95
Thu, 02 Nov 2006 20:40:39 GMT
Right Ascension 10 : 44.0 (h:m)
Declination +11 : 42 (deg:m)
Distance 38000 (kly)
Visual Brightness 9.7 (mag)
Apparent Dimension 4.4x3.3 (arc min)
Discovered by Pierre Méchain in 1781.
Pierre Méchain discovered M95, together with M96, March 20, 1781. Consequently, Charles Messier included it in his catalog on March 24, 1781.
M95 is a barred spiral of type SBb, or SB(r)ab according to de Vaucouleurs' classification, with nearly circular arms. Alan Sandage, in the Hubble Atlas of Galaxies, calls it a "typical ringed galaxy". Its overall appearance is quite similar to M91 except that M95 has more pronounced spiral structure.
M95 is a member of the Leo I or M96 group, which also contains M96, M105 and a number of fainter galaxies. (Source SEDS)]]>Astrophotographyhttp://ironwoodobservatory.com/gallery/details.php?image_id=29M 57 The Ring Nebula
Thu, 02 Nov 2006 20:38:09 GMT
Right Ascension 18 : 53.6 (h:m)
Declination +33 : 02 (deg:m)
Distance 2.3 (kly)
Visual Brightness 8.8 (mag)
Apparent Dimension 1.4x1.0 (arc min)
Discovered by Antoine Darquier de Pellepoix in 1779.
The famous ring nebula M57 is often regarded as the prototype of a planetary nebula, and a showpiece in the northern hemisphere summer sky. Recent research has confirmed that it is, most probably, actually a ring (torus) of bright light-emitting material surrounding its central star, and not a spherical (or ellipsoidal) shell, thus coinciding with an early assumption by John Herschel. Viewed from this equatorial plane, it would thus more resemble the Dumbbell Nebula M27 or the Little Dumbbell Nebula M76 than its appearance we know from here: We happen to view it from near one pole.
The central star was discovered in 1800 by the German astronomer Friedrich von Hahn (1742-1805), with a 20-foot FL reflector. This object is a planet-sized white dwarf star, which shines at about 15th magnitude. It is the remainder of a sunlike star, probably once of more mass than our sun, which has blown away its outer envelopes at the end of its Mira-like phase of evolution. Now over 100,000 K hot, it will soon start to cool down, shine as a white dwarf star for a while of several billions of years, and then eventually end as a cold Black Dwarf.
From the expansion rate of one arc second per century given above, the age of the nebula can be roughly estimated under the assumption of constant expansion. For its extension of 60x80 arc seconds, this yields a time of expansion of about 6,000 to 8,000 years.
The mass of the nebular matter has been estimated at about 0.2 solar masses, the density at about 10,000 ions per ccm (cm^3). Its chemical composition has been determined as follows: On each Fluor (Fl) atom, the Ring Nebula contains 4.25 million atoms of Hydrogene (H), 337,500 Helium (He), 2,500 Oxygene (O), 1,250 Nitrogene (N), 375 Neon (Ne), 225 Sulfur (S), 30 Argon (Ar) and 9 Chlorine (Cl) atoms. It is expanding at 20 to 30 km/s, and approaching us at 21 km/s. (Source SEDS)]]>Astrophotographyhttp://ironwoodobservatory.com/gallery/details.php?image_id=28M33
Thu, 02 Nov 2006 20:37:02 GMT
Right Ascension 01 : 33.9 (h:m)
Declination +30 : 39 (deg:m)
Distance 3000 (kly)
Visual Brightness 5.7 (mag)
Apparent Dimension 73x45 (arc min)
Probably discovered by Hodierna before 1654. Independently discovered by Charles Messier 1764.
The Triangulum galaxy M33 is another prominent member of the Local Group of galaxies. This galaxy is small compared to its big apparent neighbor, the Andromeda galaxy M31, and to our Milky Way galaxy, but by this more of average size for spiral galaxies in the universe. One of the small Local Group member galaxies, LGS 3, is possibly a satellite of M33, which itself may be a remote but gravitationally bound companion of the Andromeda galaxy M31.
M33 was probably first found by Hodierna before 1654 (perhaps together with open cluster NGC 752). It was independently rediscovered by Charles Messier, and cataloged by him on August 25, 1764. Nevertheless, William Herschel, who otherwise carefully avoided to number Messier's objects in his survey, assigned it the number H V.17, on the ground of an observation dated September 11, 1784. Also because of the cataloging of Herschel, the brightest and largest HII region (diffuse emission nebula containing ionized hydrogene) has obtained a NGC number of its own: NGC 604 (William Herschel's H III.150); it is situated in the northeastern part of the galaxy; apparently the bright knot near the top of our image. This is one of the largest H II regions known at all: it has a diameter of nearly 1500 light-years, and a spectrum similar to the Orion nebula M42. Hui Yang (University of Illinois) and Jeff J. Hester (Arizona State University) have taken a photograph of NGC 604 with the Hubble Space Tepescope, resolving over 200 young hot massive stars (of 15 to 60 solar masses) which have recently formed here.
M33 was among the first "spiral Nebulae" identified as such by William Parsons, the Third Earl of Rosse; see his drawing. It was also among the first "nebulae" identified as galaxies, in which Cepheid variable stars were found; Edwin Hubble published a fundamental study in 1926 (Hubble 1926).
Several other knots in the spiral arms of M33 have been assigned their own NGC catalog numbers: NGCs 588, 592, 595, and NGC 603 (the latter is listed as nonexistent in the RNGC though, although they mention it was listed by Zwicky), as well as ICs 131, 132, 133, 134, 135, 136, 137, 139-40, 142, and 143 (NGC 2000.0 lists IC 134 and 139-40 as stellar, while the Webb Society Deep-Sky Observer's Handbook, Vol. 4 [Galaxies] shows IC 139-40 on the chart on p. 215, which is credited to Ronald J. Buta of McDonald Observatory, University of Texas). Some of them are identified in our map also. Kenneth Glyn Jones notes that they should be visible in 12.5-inch telescopes. The giant emission nebula NGC 595 was investigated by William H. Waller with the HST (e.g. Astronomy, June 1995, p. 16-18); with Hubble he resolved the hot massive stars that excite that nebula's gas to shine.
The Triangulum galaxy M33 is of type Sc, and even a "late" representative of that type so that Tully classifies it as Scd (in the Nearby Galaxies Catalog). The pronounced arms exhibit numerous reddish HII regions (including NGC 604), as well as blueish clouds of young stars. Baade has also discovered Population II stars, and globular clusters have been found. Although no supernovae have yet been detected in the Triangulum galaxy, several supernova remnants have, and were cartographed by radio astronomers with high acuracy. At least 112 variables have been discovered in M33, including 4 novae and about 25 Cepheids. A strong X-ray source is also situated in this galaxy. (Source SEDS)]]>Astrophotographyhttp://ironwoodobservatory.com/gallery/details.php?image_id=27NGC 7293 Helix Nebula
Thu, 02 Nov 2006 20:33:20 GMT
22 : 29.6 (h:m)
Declination -20 : 48 (deg:m)
Distance 0.45 (kly)
Visual Brightness 7.3 (mag)
Apparent Dimension 16 / 28 (arc min)
Discovered by Karl Ludwig Harding before 1824.
The Helix Nebula is one of the closest of all planetary nebulae: Lying at a distance of perhaps 450 light years, it is the only planetary nebula for which a parallax could be obtained by ground-based observations. Nevertheless, its distance is quite uncertain: The first determination by A. Van Maanen yielded about 85 light-years, Becvar (1961) has 590, L. Kohoutek (1962) 280, I.S. Shlovskii (1956) and P.A. Ianna & H.A. McAlister (1974) 160, the Sky Catalogue 2000.0 gives about 300 ly, and C.R. O'Dell (1963) obtains 450 light-years.
It is also one of the apparently largest planetaries known: Its apparent size covers an area of 16 arc minutes diameter, more than half of that of the full moon; it halo extends even further to 28 arc minutes or almost the moon's apparent diameter
Although the nebula is quite bright, its light is spread over this large area so that it is not an easy object for visual observing; the Herschels have apparently never cataloged or observed it.
The popular name Helix Nebula refers to the nebula's appearance on photographs.
(Source SEDS)]]>Astrophotographyhttp://ironwoodobservatory.com/gallery/details.php?image_id=26NGC4038-NGC4039 Antennae,Ring-tail Galaxy
Thu, 02 Nov 2006 20:31:26 GMT
Explanation: This galaxy is having a bad millennium. In fact, the past 100 million years haven't been so good, and probably the next billion or so should be quite tumultuous. NGC 4039 was a normal spiral galaxy, minding its own business, when NGC 4038 crashed into it. The evolving wreckage, known as the "Antennae", is pictured above. As gravity pulls each galaxy apart, clouds of gas slam into each other and bright blue knots are formed. These knots are large clusters of stars imbedded in vast regions of ionized hydrogen gas. The high abundance of relatively dim star clusters is quite unlike our Milky Way's globular cluster system, though. Perhaps some of these young star clusters will go on to form globular clusters, while others will disperse through close gravitational encounters. The two faint lines extending from the galaxies are stars being ejected from the galaxy collision.
Dreyer description: Pretty bright, considerably large, round, very gradually brighter middle.
Other ID: ESO572-47
Other ID: MCG-3-31-14
Other ID: UGCA264
Other ID: PGC37967
RA: 12h 02m 02.8s Dec: -18°53'05"
RA: 12h 01m 52.8s Dec: -18°51'54" (Epoch 2000)
Source: The Sky]]>Astrophotographyhttp://ironwoodobservatory.com/gallery/details.php?image_id=25NGC 2359 Thor's Helmet Nebula
Thu, 02 Nov 2006 20:13:29 GMT
Declination: -13 : 12 (degrees : minutes)
Apparent Diameter: 8. (arc minutes)
A name like "Thor's Helmet" seems to imply qualities of power and strength. In the case of this nebula all of the power and strength is derived from the very energetic star in the center of the bubble of gas. This unusual star is classified as being "Wolf-Rayet" type and is very rare. These stars are incredibly hot (25,000-50,000K) and expell their outer layers of gas at tremendous velocities (thousands of kilometers per second). This particular star lives in an area of the galaxy (at least 10000 light years away) that contains clouds of interstellar gas. Thus, this Wolf-Rayet star has blown a bubble of gas in its neighborhood for us to see! Another example of this phenomena is the Bubble Nebula . (Sources SEDS and NOAO)]]>Astrophotographyhttp://ironwoodobservatory.com/gallery/details.php?image_id=24M83
Thu, 02 Nov 2006 20:01:28 GMT
Declination -29 : 52 (deg:m)
Distance 15 million light years
Visual Brightness 7.6 (mag)
Apparent Dimension 11x10 (arc min)
Discovered 1751-52 by Abbe Nicholas Louis de la Caille.
M83 was classified as intermediate between normal and barred spiral galaxies by G. de Vaucouleurs, in his classification this is SAB(s)c. M83 has very well defined spiral arms and displays a very dynamic appearance, appealing by the red and blue knots tracing the arms. The red knots are apparently diffuse gaseous nebulae in which star formation is just taking place, and which are excited to shine by its very hot young stars. The blue regions represent young stellar populations which have formed shortly (i.e., some million or some dozens of million years ago). Between the pronounced spiral arms are regions with fewer stars. Dark dust lanes follow the spiral structure throughout the disk, and may be traced well into the central region to the nucleus, which has only 20" diameter. This nucleus shows strong emission lines. It is composed of an older yellowish stellar population which dominates the whole central region, and extends along the barlike structure.
This galaxy is sometimes called the "Southern Pinwheel". It forms a small physical group with the peculiar radio galaxy Centaurus A (NGC 5128) and the unusual galaxy NGC 5253 in Centaurus. R. Brent Tully also lists the following smaller and fainter presumable (or possible) members of this group: NGC 4945, NGC 5102, NGC 5164, NGC 5408, ESO 381-20 (MCG-6-28-017; 1243-33), ESO 324-24 (MCG-6-30-003; 1324-41), ESO 444-84 (MCG-5-32-000; 1334-27), ESO 325-11 (1342-41), and ESO 383-87 (MCG-6-30-025; 1346-35).
Five or six supernovae were reported in M83 up to now, more than in any other Messier galaxy:
1923A was observed by C.O. Lampland at Lowell Observatory at mag 14.
1945B appeared on July 13, 1945 and reached mag 14.2). This supernova was only detected in 1990 by W. Liller on photographic plates taken at Harvard's station at Bloemfontein (South Africa), and could be traced from July 13 to August 7 (see IAU Circular 5091).
1950B was observed by G. Haro and reached mag 14.5 in its maximum,
1957D was discovered by H.S. Gates on December 13, 1957 and reached only mag 15.0, it was about 3' NNE of the nucleus.
Supernova 1968L was discovered visually by amateur astronomer Jack C. Bennett of Pretoria, South Africa, when sweeping for comets; this was a type I, located 5" preceding the nucleus and reached mag 11 to 12.
1983N appeared on July 3, 1983 and became as bright as 12.5 mag.
For years, M83 had been the galaxy with most discovered supernovae, but recently NGC 6946 came up with the same number of 6, or even one more if 1945B should be an error.
M83 was discovered by Abbe Nicholas Louis de la Caille at the Cape of Good Hope in 1751-52, it was his object Lacaille I.6. Thus it became the first galaxy discovered beyond the Local Group. It was next cataloged by Charles Messier on February 17, 1781; from his mid-northern location in Paris (at 49 degrees Northern latitude), it is such a difficult object that he stated that: "One is only able with the greatest concentration to see it at all." The present author can confirm it is one of the most difficult Messier objects from South Germany. Due to this fact, older Northern-compiled catalogs tended to underestimate its brightness considerably; e.g., Becvar has it at a mere 10.1 mag only.
Early 19th century Australian observer James Dunlop has it as No. 628 in his catalog. Its spiral structure was noted and sketched by William Lassell who described it as a "three-branched spiral."
M83 is one of the showpieces in the southern deep sky, but difficult for mid-northern observers, as already stated. It is even rather difficult to find: First locate one of the stars Gamma or Pi Hydrae. It can be found either by star hopping from Gamma Hydrae (mag 3.00, spectral type G5 III) which is 6.5 deg N and 3deg 15' (19 min in RA) W, or from Pi Hydrae (3.27 mag, spectral type K2 III) from which M83 is about 3deg 15' S and 6deg 20' W. Following a trail of 5th to 7th mag stars, one arrives at a yellowish 5.83-mag star of spectral type F6 and a mag 7.0 white star (spectrum A5 V) which lie about 30' NE of M83. Star hopping from Gamma will bring you close to NGC 5061 (H 1.138), an elliptical galaxy of mag 10.2.
Southerners may find it easier by locating M83 from the constellation Centaurus, as it is just north of the border from Hydra to this constellation. From Iota and Theta Centauri, in the Head of the Centaurus figure, locate the stars i, h and k (mentioned by Messier) as well as g Centauri, all between mag 4 and 5. g and h just point to M83 (and further to Gamma Hydrae); the galaxy comes beyond h, at double distance from it than has g. (Source SEDS)]]>Astrophotographyhttp://ironwoodobservatory.com/gallery/details.php?image_id=23