M51 Whirlpool Galaxy NGC 5197
3/20/2009 9:10 PM Latitude: 44°03’00.0″North Longitude: 123°05’0.0″West, 380 feet/116 meters, Backyard- Eugene, OR. Seeing: VG Transparency: 5 SQM:19.91 Bortle: 5. Telescopes / Optics: TEC 140 f/7 980mm Mount: AstroPhysics 1200 GOTO. Camera: SBIG ST10XME CFW 9. FOV: 52’ x 35’ Filter: LRGB Astrodon E series Information: L-5min. X 24 RGB 5 min. x 4 Total 3 hours. Captured with CCDSoft, processed AIP4Win, CCDStack, PhotoShop. Amazing what a CCD can do in light polluted Bortle 5 skies!
M51 Whirlpool Galaxy NGC 5197
The Whirlpool Galaxy M51, is located within the constellation Canes Venatici (Hunting Dogs). Just down 3.5° from the last star of the handle of the Big Dipper (URSA Major).
M51 lies 23 million light years from earth and is viewed by amateurs and professionals alike. Several background galaxies are also visible in the image. The Whirlpool Galaxy M51 (14.2 x 9.5 arc minutes) is interacting with it’s companion Galaxy NGC5195 (8.9 x 7.4 arc minutes). Both galaxies have a magnitude of 8.35 & 9.49 respectfully. They are not visible to the unaided eye. The Whirlpool Galaxy is approximately 60,000 light year across. They do show up in good quality binoculars.
Charles Messier discovered M51 on October 13,1773. William Parsons, in 1845, using a 72″ reflecting telescope in Ireland, discovered the Whirlpool Galaxy had a spiral structure. It was considered a nebula until Edwin Hubble established that these so called nebula were really separate and distinct galaxies. Hubble accomplished this by observing Cepheid variables in the early to mid-twentieth century.
Today a good 150mm (6″) telescope can reveal the spiral structure of M51 the Whirlpool Galaxy. Good quality binoculars will show the Whirlpool Galaxy M51a a fussy spot.
Note:
The edge-on galaxy lower right is IC 4263 (UGC8470), magnitude 15.7 and 1.8 x 0.4 arc-minutes in size, it lies 18 arc minutes South of M51.