NGC/IC Project Restoration Effort

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NGC1097

 

Basic Information


Location and Magnitude


Right Ascension: 2:46:19.5
Declination: -30:16:32
Constellation: FOR
Visual Magnitude: 9.5

Historic Information


Discoverer: Herschel W.
Year of discovery: 1790
Discovery aperture: 18.7

Observational


Summary description: vB, L, vmE 151°, vbMN
Sub-type: SBb

Steve's Notes

===== NGC 1097 30" (10/13/15 - OzSky): NGC 1097 was one of the top highlights of my October 2015 trip to Australia. At 303x; this showpiece barred spiral contains a bright central bar ~4.5'x1.5' NW-SE. The bar is sharply concentrated with an extremely bright, slightly elongated NW-SE core but no distinct stellar nucleus. A prominent spiral arm is attached on the northwest end of the bar. The arm is relatively thin, well defined and knotty as it curls counterclockwise to the east, dimming out gradually about 3' ENE of center. A large bright knot is close to the northwest end of the bar, just inside the beginning of the arm and close east of a superimposed mag 14.5 star. NED catalogues this region with the multiple designations NGC 1097:[EKS96] 148 and [EKS96] 151 from the 1996 "An Atlas of H II Regions in Nearby Seyfert Galaxies" in ApJS, 105, 93. Roughly halfway along its length is a pair of fairly prominent HII knots. The first is [EKS96] 245, a 12" knot 2.5' NNE of center. Close east is slightly larger [EKS96] 300/304, 2.5' NE of center. The arm then fades as it passes just south of a mag 15 star. At the southeast end of the bar a delicate, thin spiral arm unfurls counterclockwise towards the northwest. About halfway along its length is a slightly brighter elongated patch extending ~30" in length, with designations [EKS96] 100/105/119 and others. The arm dims out about 3' WSW of center. The arms stretch about 6' tip to tip, giving overall dimensions of perhaps 7'x6'. The satellite galaxy NGC 1097A is superimposed in the halo on the northwest side, 3.3' from center. It appeared moderately bright, fairly small, elongated 2:1 WNW-ESE, 40"x20". 18" (12/30/08): very bright, large, very elongated NW-SE. The brightest portion is the entire central "bar" which extends ~5'x1.5'. This region is surrounded by a much fainter "halo", increasing the size to ~5'x3'. The center is strongly concentrated to a very bright 50"x40" core, slightly elongated NW-SE. At the northwest end of the bar, a very diffuse arm sweeps to the east in a counterclockwise direction for ~2.5' in length and appears to brighten or have a faint knot near the end. At the southeast end of the bar, only a hint of a short extension sweeping west was detected. A faint star (mag ~14.5) is along the west side at the northwest end of the main bar, near where the brighter arm is attached. NGC 1097A, a small companion galaxy, is situated just off the NW side and appeared faint, very small, irregularly round, 25"x20". 17.5" (10/17/87): very bright, very large, very elongated NW-SE, very bright core. A companion galaxy NGC 1097A is attached at the NW end. 8" (10/13/81): bright, elongated NW-SE, bright core.