mfoylan
Arp Peculiar Object Number 027 - Spiral Galaxy with One Heavy Arm
NGC 3631 (Arp 27 = PGC 34767)
Discovered (Apr 14, 1789) by William Herschel
Also observed (date?) by John Herschel
A magnitude 10.4 spiral galaxy (type SA(s)c?) in Ursa Major (RA 11 21 02.9, Dec +53 10 10)
Historical Identification: Per Dreyer, NGC 3631 (= GC 2379 = JH 858 = WH I 226, 1860 RA 11 13 06, NPD 36 03.1) is "pretty bright, large, round, suddenly very much brighter middle and mottled but not resolved nucleus".
Physical Information: Based on recessional velocity of 1155 km/sec, about 50 million light years away, in fair agreement with a redshift-independent distance estimate of 70 million light years. Given those values and an apparent size of 4.5 by 4.5 arcmin, about 80 thousand light years across.
"Excerpt courtesy of Courtney Seligman"
cseligman.com/text/atlas/ngc36.htm#3631
Image... Cherryvalley Observatory (I83). Telescope: 0.2-m SCT & SBIG STL-1301E CCD Camera @f7.6. Image Scale 2.17 arcsec/pixel, Field of View 46 x 37 arcmins.
Flat field and dark subtract calibration frames. Combined Stack of three images of 120 seconds each unfiltered and unbinned. CCD operating temperature: -35 degrees. Image acquisition and processing: CCD Soft v5, TheSky6 Professional and Mira Pro v7. February 18th 2016.
Dr. Halton Arp originally compiled the Atlas of peculiar galaxies with photographs he made mainly using the Palomar 200-inch telescope and the 48-inch Schmidt telescope between the years 1961 to 1966. Original image can be found here:
Arp Peculiar Object Number 027 - Spiral Galaxy with One Heavy Arm
NGC 3631 (Arp 27 = PGC 34767)
Discovered (Apr 14, 1789) by William Herschel
Also observed (date?) by John Herschel
A magnitude 10.4 spiral galaxy (type SA(s)c?) in Ursa Major (RA 11 21 02.9, Dec +53 10 10)
Historical Identification: Per Dreyer, NGC 3631 (= GC 2379 = JH 858 = WH I 226, 1860 RA 11 13 06, NPD 36 03.1) is "pretty bright, large, round, suddenly very much brighter middle and mottled but not resolved nucleus".
Physical Information: Based on recessional velocity of 1155 km/sec, about 50 million light years away, in fair agreement with a redshift-independent distance estimate of 70 million light years. Given those values and an apparent size of 4.5 by 4.5 arcmin, about 80 thousand light years across.
"Excerpt courtesy of Courtney Seligman"
cseligman.com/text/atlas/ngc36.htm#3631
Image... Cherryvalley Observatory (I83). Telescope: 0.2-m SCT & SBIG STL-1301E CCD Camera @f7.6. Image Scale 2.17 arcsec/pixel, Field of View 46 x 37 arcmins.
Flat field and dark subtract calibration frames. Combined Stack of three images of 120 seconds each unfiltered and unbinned. CCD operating temperature: -35 degrees. Image acquisition and processing: CCD Soft v5, TheSky6 Professional and Mira Pro v7. February 18th 2016.
Dr. Halton Arp originally compiled the Atlas of peculiar galaxies with photographs he made mainly using the Palomar 200-inch telescope and the 48-inch Schmidt telescope between the years 1961 to 1966. Original image can be found here: