martinsastro

Astronomy for all.
Last additions - Martin
Cheriocrop.jpg
Cheriocrop.jpgCherio nebula.363 viewsM57 is located in Lyra, south of its brightest star Vega. Vega is the northwestern vertex of the three stars of the Summer Triangle. M57 lies about 40% of the angular distance from β Lyrae to γ Lyrae.[5]

M57 is best seen through at least a 20 cm (8-inch) telescope, but even a 7.5 cm (3-inch) telescope will show the ring.[5] Larger instruments will show a few darker zones on the eastern and western edges of the ring, and some faint nebulosity inside the disk.

This nebula was discovered by Antoine Darquier de Pellepoix in January, 1779, who reported that it was "...as large as Jupiter and resembles a planet which is fading." Later the same month, Charles Messier independently found the same nebula while searching for comets. It was then entered into his catalogue as the 57th object. Messier and William Herschel also speculated that the nebula was formed by multiple faint stars that were unable to resolve with his telescope.[6][7]

In 1800, Count Friedrich von Hahn discovered the faint central star in the heart of the nebula. In 1864, William Huggins examined the spectra of multiple nebulae, discovering that some of these objects, including M57, displayed the spectra of bright emission lines characteristic of fluorescing glowing gases. Huggins concluded that most planetary nebulae were not composed of unresolved stars, as had been previously suspected, but were nebulosities.[8][9]
MartinOct 19, 2010
potholomy.jpg
potholomy.jpgNGC6475.436 viewsMessier 7 or M7, also designated NGC 6475 and sometimes known as the Ptolemy Cluster, is an open cluster of stars in the constellation of Scorpius.

The cluster is easily detectable with the naked eye, close to the "stinger" of Scorpius. It has been known since antiquity; it was first recorded by the 1st century astronomer Ptolemy, who described it as a nebula in 130 AD. Giovanni Batista Hodierna observed it before 1654 and counted 30 stars in it. Charles Messier catalogued the cluster in 1764 and subsequently included it in his list of comet-like objects as 'M7'.

Telescopic observations of the cluster reveal about 80 stars within a field of view of 1.3° across. At the cluster's estimated distance of 800-1000 light years this corresponds to an actual diameter of 18-25 light years. The age of the cluster is around 220 million years while the brightest star is of magnitude 5.6.
MartinOct 19, 2010
jewelbox.jpg
jewelbox.jpgJewelbox.409 viewsThe Jewel Box (also known as NGC 4755, the Kappa Crucis Cluster and Caldwell 94) is an open cluster in the constellation of Crux. As Kappa Crucis, it has a Bayer designation despite the fact that it is a cluster rather than an individual star.

It is one of the finest open clusters discovered by Nicolas Louis de Lacaille when he was in South Africa during 1751–1752. This cluster is one of the youngest known, with an estimated age of only 7.1 million years. It has an apparent magnitude of 4.2, and is located 6,440 light years from Earth and contains around 100 stars.

This famous group of young bright stars was named the Jewel Box from its description by Sir John Herschel as "a casket of variously coloured precious stones," which refers to its appearance in the telescope. The bright orange star Kappa Crucis contrasts strongly against its predominantly blue, hot companions. Kappa Crucis is a very large (hence very luminous) young star in its red supergiant stage, which paradoxically indicates that its life is drawing to a close. The cluster looks like a star to the unaided eye and appears close to the easternmost star of the Southern Cross, (Beta Crucis), so is only visible from southern latitudes.
MartinOct 19, 2010
6067_done.jpg
6067_done.jpgNGC6067.869 viewsNGC 6067 is a bright open cluster deep South in the Constellation of Norma. Because it is located in the same plane of the Milky Way it has a dense star background. A nice target for small telescopes even from urban skies. The cluster contains about 100 stars between 8 magnitude and fainter.MartinOct 19, 2010
sombrerocrop.jpg
sombrerocrop.jpgSombrero galaxy.422 viewsThe Sombrero Galaxy (also known as M 104 or NGC 4594 ) is an unbarred spiral galaxy in the constellation Virgo. It has a bright nucleus, an unusually large central bulge, and a prominent dust lane in its inclined disk. The dark dust lane and the bulge give this galaxy the appearance of a sombrero. The galaxy has an apparent magnitude of +9.0, making it easily visible with amateur telescopes. The large bulge, the central supermassive black hole, and the dust lane all attract the attention of professional astronomers.MartinOct 18, 2010
sculptor-1.jpg
sculptor-1.jpgSculptor galaxy.456 viewsThe Sculptor Galaxy (NGC 253) is an intermediate spiral galaxy in the constellation Sculptor. The Sculptor Galaxy is a starburst galaxy, which means that it is currently undergoing a period of intense star formation.MartinOct 18, 2010
Nonet1final.jpg
Nonet1final.jpgNonet (the eyes).384 viewsThe Eyes Galaxies (NGC 4435-NGC 4438, also known as Arp 120) are a pair of galaxies about 52 million light-years away in the constellation Virgo. NGC 4438 is the most curious interacting galaxy in the Virgo Cluster, due to the uncertainty surrounding the energy mechanism that heats the nuclear source; this energy mechanism may be a starburst region, or a Black Hole embedded in an active galactic nucleus (AGN). Both of the hypotheses are still being investigated.

Additionally, there is evidence to suggest that the environmental damage to the interstellar medium of NGC 4438 may have been caused by an encounter (off-center collision) with NGC 4435, millions of years ago.
MartinOct 18, 2010
ngc6822_done1Mb.jpg
ngc6822_done1Mb.jpgNgc6822.347 viewsNGC 6822 (also known as Barnard's Galaxy or IC 4895) is a barred irregular galaxy approximately 1.6 million light-years away in the constellation Sagittarius. Part of the Local Group of galaxies, it was discovered by E. E. Barnard in 1881 (hence its name), with a six-inch refractor telescope. It is one of the closer galaxies to the Milky Way. It is similar in structure and composition to the Small Magellanic Cloud.MartinOct 18, 2010
galaxiesdone.jpg
galaxiesdone.jpgUnknown.352 viewsJust a picture of some galaxies.MartinOct 18, 2010
Centaurusdone1.jpg
Centaurusdone1.jpgCentaurus A.359 viewsThe Centaurus A/M83 Group is a complex group of galaxies in the constellations Hydra, Centaurus, and Virgo. The group may be roughly divided into two subgroups. The Cen A Subgroup, at a distance of 11.9 Mly (3.66 Mpc), is centered around Centaurus A, a nearby radio galaxy.[3] The M83 Subgroup, at a distance of 14.9 Mly (4.56 Mpc), is centered around the Messier 83 (M83), a face-on spiral galaxy.[3]

This group is sometimes identified as one group[4][5] and sometimes identified as two groups.[6] Hence, some references will refer to two objects named the Centaurus A Group and the M83 Group. However, the galaxies around Centaurus A and the galaxies around M83 are physically close to each other, and both subgroups appear not to be moving relative to each other.[3]

The Centaurus A/M83 Group is part of the Virgo Supercluster, the local supercluster of which the Local Group is an outlying member.
MartinOct 18, 2010
centaurus-A.jpg
centaurus-A.jpgCentaurus A.449 viewsThe Centaurus A/M83 Group is a complex group of galaxies in the constellations Hydra, Centaurus, and Virgo. The group may be roughly divided into two subgroups. The Cen A Subgroup, at a distance of 11.9 Mly (3.66 Mpc), is centered around Centaurus A, a nearby radio galaxy.[3] The M83 Subgroup, at a distance of 14.9 Mly (4.56 Mpc), is centered around the Messier 83 (M83), a face-on spiral galaxy.[3]

This group is sometimes identified as one group[4][5] and sometimes identified as two groups.[6] Hence, some references will refer to two objects named the Centaurus A Group and the M83 Group. However, the galaxies around Centaurus A and the galaxies around M83 are physically close to each other, and both subgroups appear not to be moving relative to each other.[3]

The Centaurus A/M83 Group is part of the Virgo Supercluster, the local supercluster of which the Local Group is an outlying member.
MartinOct 18, 2010
Centaurus_done.jpg
Centaurus_done.jpgCentaurus A.469 viewsThe Centaurus A/M83 Group is a complex group of galaxies in the constellations Hydra, Centaurus, and Virgo. The group may be roughly divided into two subgroups. The Cen A Subgroup, at a distance of 11.9 Mly (3.66 Mpc), is centered around Centaurus A, a nearby radio galaxy.[3] The M83 Subgroup, at a distance of 14.9 Mly (4.56 Mpc), is centered around the Messier 83 (M83), a face-on spiral galaxy.[3]

This group is sometimes identified as one group[4][5] and sometimes identified as two groups.[6] Hence, some references will refer to two objects named the Centaurus A Group and the M83 Group. However, the galaxies around Centaurus A and the galaxies around M83 are physically close to each other, and both subgroups appear not to be moving relative to each other.[3]

The Centaurus A/M83 Group is part of the Virgo Supercluster, the local supercluster of which the Local Group is an outlying member.
MartinOct 18, 2010
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