Steve Gottlieb
August 2nd, 2014, 07:30 PM
This small group (listed in NED as Arp 311 = WBL 640) contains the close pair VV 101 = Arp 310 = IC 1259, so we get an Arp within an Arp, and a total of 5 galaxies in a 3.5'-diameter rhombus! Arp 311 is also the core of a larger cluster, SDSS-C4-DR3 3143, found on the third release of the SDSS, with a population of roughly 45 members and a mean redshift of z = .028. This yields a light-travel time of ~385 million l.y.
Arp 311 is a fascinating group in 18" and larger scopes and one of the targets from Lassen National Park at the Devastated area. The transparency and seeing that night were superb, although we had a pretty consistent wind that limited using high magnification.
1313
At 375x, the merged contact pair IC 1259 (15" between centers) was a striking sight. VV 101a, the larger and brighter eastern component, appeared fairly faint, small, round, 18" diameter. A mag 15 star is at the southeast edge, just 10" from center. VV 101b, the western component, appeared very faint, extremely small, 8" x 5" SW-NE. In addtion, a mag 12 star lies 0.8' NE. Quite a collection of objects in a small region!
IC 1258, just 2.2' SW, is another fascinating object because of several nearby stars. It appeared faint or fairly faint, elongated 4:3 WSW-ENE, ~0.4'x0.3'. A mag 15.3 star is off the north side [27" from center] and another mag 15 star is off the southwest side [44" from center]. At 500x, a mag 15.5+ star is at the east edge [10" from center!]. Alvin identifies this object as a close companion galaxy in his Arp observing guide, but it appears completely stellar on the SDSS. Does anyone have additional information on whether IC 1258 is a double galaxy?
IC 1260 is 2.5' SSE of IC 1259 and also appeared faint to fairly faint, round, 12" diameter. Megastar misidentifies this galaxy as KAZ 140 (see NED for the correct identification).
FInally, PGC 2579433 = MAC 17275829 at 2.5' ESE of IC 1259 is the toughest of the group and logged as extremely faint, roundish, 8" diameter, required averted vision.
The three IC galaxies were discovered visually by Lewis Swift in the late 1880s with his 16" Clark refractor in Rochester, New York, which is pretty impressive.
If you check out this group, just 1° southwest is UGC 10822, better known as the Draco Dwarf, another challenging object.
Arp 311 is a fascinating group in 18" and larger scopes and one of the targets from Lassen National Park at the Devastated area. The transparency and seeing that night were superb, although we had a pretty consistent wind that limited using high magnification.
1313
At 375x, the merged contact pair IC 1259 (15" between centers) was a striking sight. VV 101a, the larger and brighter eastern component, appeared fairly faint, small, round, 18" diameter. A mag 15 star is at the southeast edge, just 10" from center. VV 101b, the western component, appeared very faint, extremely small, 8" x 5" SW-NE. In addtion, a mag 12 star lies 0.8' NE. Quite a collection of objects in a small region!
IC 1258, just 2.2' SW, is another fascinating object because of several nearby stars. It appeared faint or fairly faint, elongated 4:3 WSW-ENE, ~0.4'x0.3'. A mag 15.3 star is off the north side [27" from center] and another mag 15 star is off the southwest side [44" from center]. At 500x, a mag 15.5+ star is at the east edge [10" from center!]. Alvin identifies this object as a close companion galaxy in his Arp observing guide, but it appears completely stellar on the SDSS. Does anyone have additional information on whether IC 1258 is a double galaxy?
IC 1260 is 2.5' SSE of IC 1259 and also appeared faint to fairly faint, round, 12" diameter. Megastar misidentifies this galaxy as KAZ 140 (see NED for the correct identification).
FInally, PGC 2579433 = MAC 17275829 at 2.5' ESE of IC 1259 is the toughest of the group and logged as extremely faint, roundish, 8" diameter, required averted vision.
The three IC galaxies were discovered visually by Lewis Swift in the late 1880s with his 16" Clark refractor in Rochester, New York, which is pretty impressive.
If you check out this group, just 1° southwest is UGC 10822, better known as the Draco Dwarf, another challenging object.