Galaxy NGC 3115

NGC 3115
NGC 3115: Image taken by Hubble Space Telescope. © NASA, ESA, J. Erwin, Gladys Kober [261]


On 22 February 1787 William Herschel discovered a «bright nebula» which he listed as I 163. He wrote: «Extremely bright, considerably large, much extended, 45° south preceding north following, having a nucleus 2' long, faint branches 5' long.» [464] John Herschel observed this nebula on 14 March 1827, listed it as h 668 (later h 3223 in his «Cape Catalogue») and wrote: «Very bright, large, much extended, very suddenly much brighter in the middle; almost to a nucleus 3' long, 30" broad. With 12 inches aperture, its nucleus is rather speckled; with 6 inches it is barely discernible as a nebula.» [466]

Lord Rosse observed the nebula on 11 March 1848 using his 72-inch telescope and noted: «Fine ray, with very bright nucleus.» [486]

NGC 3115 is sometimes also called «Spindle Galaxy». But this name is rather used for Messier 102.

Physical Properties

NGC 3115 is a lenticular galaxy that we see edge-on. It lacks spiral arms but boasts a galactic bulge and prominent disk. It hosts an elderly stellar population and has used up nearly all of its star-forming material. It is located about 32 million light-years away. In the center is a supermassive black hole with the mass of roughly one billion (109) times the mass of our Sun. [261]

Revised+Historic NGC/IC Version 22/9, © 2022 Dr. Wolfgang Steinicke [277]
Designation NGC 3115
Type Gx (E-S0)
Right Ascension (J2000.0) 10h 05m 14.1s
Declination (J2000.0) -07° 43' 05"
Diameter 7.2 × 2.4 arcmin
Photographic (blue) magnitude 9.9 mag
Visual magnitude 8.9 mag
Surface brightness 11.9 mag·arcmin-2
Position Angle 40°
Redshift (z) 0.002212
Distance derived from z 9.34 Mpc
Metric Distance 10.070 Mpc
Dreyer Description vB, L, vmE 46°, vgsmbMEN
Identification, Remarks WH I 163; h 668=3223; GC 2008; MCG -1-26-18; UGCA 199; Spindle galaxy

Finder Chart

The galaxy NGC 3115 is located in the constellation Sextans. It can best be observed from December to May.

Finder Chart Galaxy NGC 3115
Galaxy NGC 3115 in constellation Sextans. Charts created using SkySafari 6 Pro and STScI Digitized Sky Survey. Limiting magnitudes: Constellation chart ~6.5 mag, DSS2 close-ups ~20 mag. [149, 160]

Objects Within a Radius of 25°


  • [149] SkySafari 6 Pro, Simulation Curriculum;
  • [160] The STScI Digitized Sky Survey;
  • [261] Explore - The Night Sky | Hubble’s Caldwell Catalog; (2021-02-08)
  • [277] «Historische Deep-Sky Kataloge» von Dr. Wolfgang Steinicke; (2021-02-17)
  • [464] «Catalogue of a second thousand of new nebulae and clusters of stars; with a few introductory remarks on the construction of the heavens» William Herschel, Philosophical Transactions of the Royal Society of London, 1 January 1789; DOI:10.1098/rstl.1789.0021
  • [466] «Observations of nebulæ and clusters of stars, made at Slough, with a twenty-feet reflector, between the years 1825 and 1833» John Frederick William Herschel, Philosophical Transactions of the Royal Society of London, 1 January 1833, Pages: 359-505; DOI:10.1098/rstl.1833.0021
  • [486] «On the construction of specula of six-feet aperture; and a selection from the observations of nebulæ made with them» William Parsons; Philosophical Transactions of the Royal Society of London, Volume 151, published 1 January 1861; DOI:10.1098/rstl.1861.0029