NGC/IC Project Restoration Effort

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NGC1365

 

Basic Information


Location and Magnitude


Right Ascension: 3:33:36.7
Declination: -36:8:27
Constellation: FOR
Visual Magnitude: 9.6

Historic Information


Discoverer: Dunlop
Year of discovery: 1826
Discovery aperture: 9.0

Observational


Summary description: !! vB, vL, mE, rN
Sub-type: SBb

Steve's Notes

===== NGC 1365 48" (10/22/11): stunning view of this huge, barred spiral with the full extent of the long, graceful arms clearly visible and a great deal of structure. The very bright bar runs nearly 3' WSW-ENE and contains an extremely bright core that increases to a striking knotty nucleus that is sliced by a dust lane running SW to NE. The dust lane creates a mini spiral in the center with a bright elongated section south of the lane that has an "arm" attached at its northeast end that curls to the southwest. The section of the nucleus north of the lane appears as a small but brighter arm, gently curving from SW to NE. The main northern spiral arm is attached at the west end of the bar and has a bright, mottled "knot" as it emerges from the bar and heads north-northeast. This knot contains the HII regions #23-25 from Paul Hodge's 1969 "HII Regions in Twenty Nearby Galaxies" (ApJS, 18, 73). It was also the site of SN 2001du, a supernova discovered visually by Robert Evans. This arm dims a bit and then brightens along a 1' strip (contains HII #19) just northwest of a superimposed mag 13.5 star. The arm then dims significantly but can be easily traced a total length of 6.5', ending just southeast of a mag 13.5-14 star. The main southern arm emerges on the east-northeast end of the bar as a brighter patch or OB association that contains #2-3, matching the west end. A group of stars is just east, beyond this patch. The arm extends ~6.5' SW and is bordered by several stars; a mag 14.5 star is on the south edge before the middle of the arm, a mag 16 star 1.3' due south of this star and two mag 15/16 stars are on the inside (northern edge) beyond the middle of the arm. A very small, very faint knot is near the southwest tip of the arm. The arm dims significantly at this point but bends and continues another 2' NW. 24" (11/18/12 - Magellan Observatory, Australia): viewed SN2012fr, a type Ia supernova, as a mag 12 star situated just 2" west and 52" north of the center of NGC 1365. 24" (4/5/08 - Magellan Observatory, Australia): this is the best visual barred spiral in the sky and although it was only at 33¡ elevation (well past the meridian), the view was stunning at 200x with its long sweeping arms making a slashing cosmic "Z" in the eyepiece. I was also surprised by the structure in the fairly small, extremely bright core that is embedded in the 3' E-W bar. On the north edge of the mottled core, a very short, hooking appendage extended towards the northeast with a fainter counterpart on the southwest end. This gave the small core the appearance of a tiny barred spiral! At the west end of the bar a bright arm emerges, dramatically sweeping back to the NNE (sharp 110¡ angle) beyond a mag 13 star that is situated near the 1/3 mark of its total length. The counterpart on the east end of the bar shoots to the southwest, reaching a faint star at its end. The total distance between the tips of the arms is roughly 10'. 20" (7/8/02 - Magellan Observatory, Australia): At 127x and 212x, NGC 1365 appeared as an amazing two-armed barred spiral, similar to the photographic appearance. The core is a quite bright, bulging oval embedded in a larger bar oriented ~E-W. Attached at opposite ends of the bar are two long, graceful arms that extend quite a distance and are nearly straight. The arm attached on the west side of the bar wraps around a mag 12.5 star about 1' NW of the core and extends well beyond towards the NNE. The opposite arm attached on the following end is slightly fainter and shoots towards the SSW. The tips of the outer arms dramatically increase the total size of the galaxy. 18" (12/30/08): although a pale imitation of the view from Australia, with careful viewing at 175x the spiral arm attached at the west end of the central bar was faintly visible sweeping to the NNE for ~3' in length. The counterpart on the SE side was not seen. 13" (12/22/84): bright, elongated core, large, 3' diameter, very diffuse outer halo. Member of the Fornax I cluster. 8" (1/1/84): fairly bright, fairly large, bright core, diffuse halo, broad concentration. 8" (9/25/81): moderately large, elongated, gradually brighter core.