TAAS Observing Challenge, March 2016

Deep Sky Object

NGC 3242 (PN) Hydra ra: 10h 24m 46.2s dec: -18° 38’ 34” Magnitude (visual) = 7.7 Size = 64” Distance = approximately 2,500 light years

Description: William Herschel discovered this planetary nebula on February 7, 1785, and cataloged it as H IV.27. John Herschel observed it from the Cape of Good Hope, South Africa, in the 1830s, and numbered it as h 3248, and included it in the 1864 General Catalogue as GC 2102; this became NGC 3242 in J.L.E. Dreyer's New General Catalogue of 1888.

This planetary nebula consists of a small dense nebula of about 16" x 26" in diameter, surrounded by a fainter envelop measuring about 40 x 35 arc seconds. This central nebula is embedded in a much larger faint halo, measuring 1250" or about 20.8 arc minutes in diameter. The bright inner nebula is described as looking like an eye by Burnham, and the outer shell gave rise to its popular name, as it is of about the apparent size of Jupiter.

This planetary nebula is most frequently called the Ghost of Jupiter, or Jupiter's Ghost, but it is also sometimes referred to as the Eye Nebula, or the CBS Eye.

Source: http://messier.seds.org/spider/Misc/n3242.html

AL: Herschel 400, Caldwell [59]; TAAS 200

Challenge Object

NGC 3962 (GX) Crater ra: 11h 54m 40.0s dec: -13° 58’ 34” Magnitude (visual) = 10.7 Size = 2.6’ x 2.2’ Position angle = 10°

Description: NGC3962 is a small, elliptical galaxy in the constellation of Crater. Although very faint, the galaxy has a bright, compact core. This galaxy is found approximately three degrees north of star eta Crateris.

AL: Herschel 400

Binocular Object

M53 (GC) Coma Berenices ra: 13h 12m 55.3s dec: +18° 10’ 09” Magnitude (visual) = 7.7 Size = 13’ Concentration Class = 5 Distance = approximately 58,000 light years

Description: Globular star cluster Messier 53 (NGC 5024) is one of the more outlying globulars, being about 60,000 light years away from the galactic center, and almost the same distance (about 58,000 light years) from our Solar system. At this distance, its apparent angular diameter of 13' corresponds to a linear diameter of roughly 220 light years. It is rapidly approaching us at a velocity given by Mallas as 112 km/s, by Harris as 79 km/s. M53 has a bright compact central nucleus of about 2' in diameter, although its stars are not very concentrated toward the center when compared to other globulars, and a gradually decreasing density profile to the outer edges. Harlow Shapley classified it in density, or concentration class V. While the NGC, following John Herschel, suspected its brightest red giant stars at about 12th magnitude, the Deep Sky Field Guide lists them at 13.8 magnitude, and the horizontal branch at about magnitude 16.9. The cluster's overall spectral type is given as F6.

Its discoverer Johann Elert Bode, who found it on February 3, 1775, described it as a "rather vivid and round" nebula. Charles Messier, who independently rediscovered and cataloged it two years later, on February 26, 1777, found it "round and conspicuous" and that it resembles M79. William Herschel was the first to resolve it into stars, and found it similar to M10.

Source: http://messier.seds.org/m/m053.html

AL: Messier, Binocular Messier

Double Star

Gamma Leporis (DS) Lepus ra: 05h 44m 27.8s dec: -22° 26’ 54.2” Magnitudes (visual) = 3.7, 6.3 Separation = approximately 97” Position angle = 350° Distance = approximately 29 light years

Description:

Gamma Leporis A: This star is a main-sequence white-yellow dwarf star of spectral and luminosity type F6-7 V. Gamma Leporis has about 1.2 times Sol's mass, about 1.3 times its diameter, and about 2.6 times of its luminosity. It appears to be less enriched than Sol in elements heavier than hydrogen ("metals") with about 72-89 percent of Sol's abundance of iron. The star may be about 2.7 billion years old. The star and its known stellar companion B have an observed separation of about 864 AU (96.3" at a HIPPARCOS parallax of 0.11149 +/- 0.00060"), but there may be as many as two optical companions.

Gamma Leporis B: This star appears to be a main-sequence orange-red star of spectral and luminosity type K2 V. The star has about 63 percent of Sol's mass, as much as the same diameter, and about 25 percent of its luminosity.

Source: http://solstation.com/stars/g-lepor2.htm

AL: Double Star, Binocular Double Star