TAAS Monthly Observing Challenge December 2015 Deep Sky Object NGC 772 (GX) Aries ra: 01h 59m 20.1s dec: +19° 00’ 26” Magnitude (visual) = 10.3 Size = 7.2’ x 4.3’ Position angle = 130° Description: NGC 772 (also known as Arp 78) is an unbarred spiral galaxy approximately 130 million light-years away in the constellation Aries. Around 200,000 light years in diameter, NGC 772 is twice the size of the Milky Way Galaxy, and is surrounded by several satellite galaxies – including the dwarf elliptical, NGC 770 – whose tidal forces on the larger galaxy have likely caused the emergence of a single elongated outer spiral arm that is much more developed than the others arms. Halton Arp includes NGC 772 in his Atlas of Peculiar Galaxies as Arp 78, where it is described as a "Spiral galaxy with a small high-surface brightness companion". Two supernovae (SN 2003 hl & SN 2003 iq) have been observed in NGC 772. Source: https://www.wikipedia.org/wiki/NGC_772 AL: Herschel 400 Challenge Object NGC 2371 / 2372 (PN) Gemini ra: 07h 25m 34.8s dec: +29° 29’ 22” Magnitude (visual) = 11.2 Size = 62” Description: NGC 2371-2 is a dual lobed planetary nebula located in the constellation Gemini. Visually, it appears like it could be two separate objects; therefore, two entries were given to the planetary nebula by William Herschel in the "New General Catalogue", so it may be referred to as NGC 2371, NGC 2372, or variations on this name. Source: https://www.wikipedia.org/wiki/NGC_2371-2 AL: Herschel 400, Planetary Nebula Binocular Object NGC 1807 (OC) Taurus ra: 05h 10m 46.0s dec: +16° 31’ 00” Magnitude (visual) = 7.0 Size = 12’ Description: NGC 1807 is an open cluster at the border of the constellations Taurus and Orion near the open cluster NGC 1817. Uranometria 2000.0 Deep Sky Field Guide describes NGC 1807 as “Few stars; moderate brightness range; slight central concentration; detached. Probably not a cluster.” Source: https://www.wikipedia.org/wiki/NGC_1807 AL: Deep Sky Binocular Double Star Lambda Orionis (DS) Orion ra: 05h 35m 08.28s dec: +09° 56’ 02.96” Magnitudes (visual) = 3.5, 5.5 Separation = 4” Position angle = 43° Distance = approximately 1100 light years Description: A binary star in the constellation Orion consisting of a hot (35,000 K) and luminous (65,000 L) O star, of about 25 solar masses located 4” away from a B star (25,000 K, 5,500 L). Meissa (also known as Hatya) is best known for a huge surrounding ring of gas, called Sh2-264 or the Meissa ring, an astonishing 150 light years across that is ionized by the star. Sh2-264 is itself set within an even larger ring of interstellar dust and molecules. These structures may be composed of material left over from the formation of Meissa that has been compressed by the action of the O star. Alternatively, it’s possible they were created from the blast of another star that exploded in the neighborhood of Meissa a few million years ago. Source: http://www.daviddarling.info/encyclopedia/M/Meissa.html AL: Double Star .