NGC 147 & NGC 185

Also Known as: Caldwell 17 (NGC 147) ... Caldwell 18 (NGC 185)

Object Type: Dwarf Spheroidal Galaxies

Constellation: Cassiopeia

Distance from Earth: 2.56 million light years (NGC 147)... 2.05 million light years (NGC 185)

Apparent Magnitude: 10.5 (NGC 147) .... 9.2 (NGC 185)

Coordinates: RA 00H 33M 12.1S DEC 48 deg 30 min 32 sec (NGC 147) .. RA 00H 38M 57.97S DEC 48deg 20min 14.56sec (NGC 185)

Actual Size: 4,400 light year in diameter (NGC 147) .. 10,000 light years in diameter (NGC 185)

Apparent Dimensions: 13.2 arc-minutes x 7.8 arc-minutes (NGC 147) ... 11.7 arc-minutes x 10.9 arc-minutes (NGC 185)

Discovered by: NGC 147 was discovered by John Herschel in September 1829.
NGC 185 was discovered by William Herschel on November 30, 1787, and he cataloged it "H II.707". John Herschel observed the object again in 1833 when he cataloged it as "h 35", and then in 1864 when he cataloged it as "GC 90" within his General Catalogue of Nebulae and Clusters.

Description: NGC 147 is a member of the Local group of galaxies and a satellite galaxy of the Andromeda Galaxy (M31).
Just as the planets in the solar system are gravitationally bound to the Sun, so are these smaller galaxies bound to their much more massive galactic host.
While many classes of galaxies can exist as satellites, dwarf spheroidal galaxies like NGC 147 have been observed in this role more frequently than any other type of galaxy.
NGC 147 forms a physical pair with the nearby galaxy NGC 185, another remote satellite of M31. The last significant star-forming activity in NGC 147 occurred around 3 billion years ago.
NGC 147 lies 300,000 light-years from M31, which is roughly twice the distance between the Large Magellanic Cloud and our Milky Way galaxy.
Dwarf satellite galaxies tend to appear very diffuse and dim, so they can be difficult to spot.
NGC 147 contains a large population of older stars which show a spread in metallicity and age.

NGC 185 is a member of the Local Group, and is a satellite of the Andromeda Galaxy (M31). Unlike most dwarf elliptical galaxies, NGC 185 contains young stellar clusters, and star formation proceeded at a low rate until the recent past.
NGC 185 has an active galactic nucleus (AGN) and is usually classified as a type 2 Seyfert galaxy, though its status as a Seyfert is questioned.
It is possibly the closest Seyfert galaxy to Earth, and is the only known Seyfert in the Local Group.

Click Below Image(s) for Full Size:

Visually NGC 147 is both fainter and slightly larger than NGC 185.
NGC 147 is more difficult to see than NGC 185, which is visible in small telescopes.
NGC 185 galaxy can be found with powerful binoculars. It is easier to spot than the neighboring Caldwell 17, because its center appears more circular and compact than that of its neighbor.

Best observing time is in the months July through January, when this circumpolar constellation is highest in the sky.

Platesolve

NGC 185 and NGC 147 Wide View

Imaging Details
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