Uwe Glahn
January 10th, 2016, 06:15 PM
Palomar 2 (= C 0443+313) [= MCG +05-12-001; PGC 15963]
Constellation: Auriga
RA: 04h 46m 06s
Dec: 31° 22’ 53”
Type: Globular Cluster, Class IX
Distance (Galactic center): 111000 ly
Distance (sun): 85000 ly
Size: 1.9’
Mag: 13.0V
Brightest Star: 18.0V
The OOTW type for the early winter season is as unusual as its location in the sky. In the SE Auriga region – between the Pleiades and Messiers famous Auriga cluster Palomar 2 is the only object of that type in that part of the sky.
But unusual not only in our perspective – Pal 2 located farthest on the sky from the Galactic center, even under all other “outer halo clusters”
But let’s start at the very beginning. A.G. Wilson discovered one unknown object on the plates of the 48-inch Schmidt telescope of the Palomar Observatory in early 1955. A little bit later, G.O. Abell listed and published a list of all in all 13 newly discovered globular clusters in late 1955 [1955PASP...67..258A (http://adsabs.harvard.edu/abs/1955PASP...67..258A)].
Because of its unusual orbit the cluster is highly obscured by dust. The immersive foreground reddening of around 1,2mag (B-V) made it very difficult to study. Modern studies with the 3,6m CFHT (http://www.cfht.hawaii.edu/) on the top of the Mauna Kea gave a more or less detailed picture of Palomar 2. [1997AJ....114.1043H (http://adsabs.harvard.edu/abs/1997AJ....114.1043H)] The photometry gave an intermediate metallicity and a distance of about 34kpc from the Galactic center.
From the observation standpoint Palomar 2 belongs to a difficult candidate of the catalog but not to an impossible object. Under dark and transparent skies a mid size telescope should show the GC. Perhaps also a smaller telescope could show something when all things around fits perfect. My notes from my Palomar Project (http://www.deepsky-visuell.de/Projekte/PalomarGC_E.htm) say:
8", 80x, NELM 6m5+ - nothing with 31x and 47x; with 80x a stellar spot is visible with averted vision at the position of the GC; not sure if the plob was the GC or the glow of the 2,3' NE 13mag star
16", 225x, NELM 6m5+ - faint GC, can hold it with averted vision; round; concentrated to its middle; diffuse edges; no stars
16", 129x, NELM 7m0+ - easier to detect than Pal 1, circular, concentrated to its middle, no stars, structureless
27", 172x, NELM 7m0+ - easy to detect; steadily with direct vision, concentrated, round plop, no stars or mottling (bad seeing)
1957
DSS blue 30'x30'
1958
NASA/ESA HST (https://www.spacetelescope.org/images/potw1315a/)
1959
16", 129x, NELM 7m0+ (http://www.deepsky-visuell.de/Zeichnungen/Pal2.htm)
As always, give it a go and let us know.
Constellation: Auriga
RA: 04h 46m 06s
Dec: 31° 22’ 53”
Type: Globular Cluster, Class IX
Distance (Galactic center): 111000 ly
Distance (sun): 85000 ly
Size: 1.9’
Mag: 13.0V
Brightest Star: 18.0V
The OOTW type for the early winter season is as unusual as its location in the sky. In the SE Auriga region – between the Pleiades and Messiers famous Auriga cluster Palomar 2 is the only object of that type in that part of the sky.
But unusual not only in our perspective – Pal 2 located farthest on the sky from the Galactic center, even under all other “outer halo clusters”
But let’s start at the very beginning. A.G. Wilson discovered one unknown object on the plates of the 48-inch Schmidt telescope of the Palomar Observatory in early 1955. A little bit later, G.O. Abell listed and published a list of all in all 13 newly discovered globular clusters in late 1955 [1955PASP...67..258A (http://adsabs.harvard.edu/abs/1955PASP...67..258A)].
Because of its unusual orbit the cluster is highly obscured by dust. The immersive foreground reddening of around 1,2mag (B-V) made it very difficult to study. Modern studies with the 3,6m CFHT (http://www.cfht.hawaii.edu/) on the top of the Mauna Kea gave a more or less detailed picture of Palomar 2. [1997AJ....114.1043H (http://adsabs.harvard.edu/abs/1997AJ....114.1043H)] The photometry gave an intermediate metallicity and a distance of about 34kpc from the Galactic center.
From the observation standpoint Palomar 2 belongs to a difficult candidate of the catalog but not to an impossible object. Under dark and transparent skies a mid size telescope should show the GC. Perhaps also a smaller telescope could show something when all things around fits perfect. My notes from my Palomar Project (http://www.deepsky-visuell.de/Projekte/PalomarGC_E.htm) say:
8", 80x, NELM 6m5+ - nothing with 31x and 47x; with 80x a stellar spot is visible with averted vision at the position of the GC; not sure if the plob was the GC or the glow of the 2,3' NE 13mag star
16", 225x, NELM 6m5+ - faint GC, can hold it with averted vision; round; concentrated to its middle; diffuse edges; no stars
16", 129x, NELM 7m0+ - easier to detect than Pal 1, circular, concentrated to its middle, no stars, structureless
27", 172x, NELM 7m0+ - easy to detect; steadily with direct vision, concentrated, round plop, no stars or mottling (bad seeing)
1957
DSS blue 30'x30'
1958
NASA/ESA HST (https://www.spacetelescope.org/images/potw1315a/)
1959
16", 129x, NELM 7m0+ (http://www.deepsky-visuell.de/Zeichnungen/Pal2.htm)
As always, give it a go and let us know.