Palomar globular star clusters

What at all are Palomar globular star clusters?

The catalog of the Palomar globular star clusters (GC) includes 15 members of all together very faint globular star cluster. Except Palomar 9 (NGC 6717) and Palomar 7 (IC 1276) all these clusters were discovered and classified very late on plates of the Palomar Observatory Sky Survey (POSS) between 1949-1959. Except its usually very faint brightness and its observing challenge these globular star clusters do not have many thing in common. Most different age, sizes and distances do not let these GC's divide clearly into an obvious scheme.

Num.	RA	DEC	Con.	Size	Uranometria 2
1	03 33 23.0	+79 34 50	Cep	1.8'	7
2	04 46 05.9	+31 22 51	Aur	1.9'	59
3	10 05 31.0	+00 04 17	Sex	2.8'	113
4	11 29 16.8	+28 58 25	UMa	2.1'	72
5	15 16 05.3	-00 06 41	Ser	6.9'	108
6	17 43 42.2	-26 13 21	Oph	1.2'	146
7 (IC 1276)	18 10 44.3	-07 12 27	Ser	7.1'	126
8	18 41 29.9	-19 49 33	Sgr	4.7'	145
9 (NGC 6717)	18 55 06.2	-22 42 01	Sgr	3.9'	145
10	19 18 02.1	+18 34 18	Sge	3.5'	66
11	19 45 14.4	-08 00 26	Aql	3.2'	124
12	21 46 38.8	-21 15 03	Cap	2.9'	143
13	23 06 44.5	+12 46 19	Peg	1.8'	82
14	16 11 00.3	+14 57 34	Her	2.1'	87
15	16 59 51.0	-00 32 31	Oph	3.0'	107

Object (DSS)	Sketch	Aperture, Faintest Star, Magnification - Description
Palomar 1 DSS 10' x 10'	Sketch (klick for enlargement)	16", 129x, fst 7m0 only with exact map to find, small, not laminar, consists of a few very faint stars 27", 113x-419x, fst 7m+ visible even in the searching eyepiece; direct vision object; best view with 4mm EP (172x); GC visible as a round, diffuse, slightly concentrated glow with 1' diameter; with higher power a foreground star is visible in the middle of the GC; some very faint stars are popping in and out of view at the edge of the GC, not steadily visible
Palomar 2 DSS 10' x 10'	Sketch (klick for enlargement)	8", 80x, fst 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, fst 6m9 faint GC, can hold it with averted vision; round; concentrated to its middle; diffus edges; no stars 16", 129x, fst 7m0 easier to detect than Pal 1, circular, concentrated to its middle, no stars, structureless 27", 172x, fst 7m0+ easy to detect; steadily with direct vision, concentrated, round plob, no stars or mottling (bad seeing)
Palomar 3 DSS 10' x 10'	Sketch (klick for enlargement)	8", 47x-80x, fst 6m5+ not visible 14,5", 88x, fst 7m+ under perfect transparency easy to detect with 4mm AP; round glow; can hold glow with averted vision; not concentrated to its middle, no stars, structureless 16", 129x, fst 6m6 no visual detection even under good sky conditions 16", 129x, fst 6m5 only with max. AP, faint, round, structureless glow 27", 113x, fst 6m5+ easy and steadily visible with averted vision; mid large, diffuse, structureless glow; with 4mm EP (171x) some stellar peaks popping in and out of view, not steadily visible; other than that no individual stars
Palomar 4 DSS 10' x 10'	Sketch (klick for enlargement)	8", 47x-80x, fst 6m5+ not visible 16", 51x, fst 6m6 extremely difficult to verify, sketch confirms successfully observation by later map alignment, GC appears somewhat larger than listed 27", 113x-419x, fst 6m5+ located without exact finder chart (only Uranometria); faint, 1' round, diffuse glow visible with direct vision with finder eyepiece (113x) 1.5' SW of a 14mag star; 172x brings no advantage; with 419x still visible, with nearly no concentration to its middle; to the W edge a 16mag star is visible with averted vision; 2-3 stars are popping in and out of view but GC shows no mottling
Palomar 5 DSS 10' x 10'	Sketch (klick for enlargement)	4" Bino, 23x, fst 6m5+ not visible or suspected even under good transparency 16", 51x, fst 6m5 first try together with Martin Schoenball, we both see somewhat faint but in wrong position, negative observation 16", 69x, fst 6m8 under good sky best view with 5,8mm AP; also with max. AP (7,8mm), not successful with 4mm AP; stands between one 9mag and one 11mag star; visually as a round, 6' large, very faint spot of light; 3-4 stars glimpsed out between the GC, can hold GC with averted vision 16", 51x, fst 7m0 finally seen under very good sky conditions; nevertheless extremely difficulty to detect; only with max. AP, large, circular wisp of light NW a mag 9 field star 27", 113x-293x, fst 6m5+ easy visible with averted vision and 113x, borders of GC clearly detectable, somewhat mottled structure within the GC; with 172x more mottling and similar visibility of the borders; from 293x up several stars within the GC, the GC itself disappears
Palomar 6 DSS 10' x 10'	Sketch (klick for enlargement)	8", 89x, fst 7m+ very faint glow, can be hold for seconds, two other observers also see the glow, a little bit concentrated to its middle 16", 129x, fst 7m0 dangerous star field; I see a group of mag 14 - mag 15 stars somewhat south of the exact position 16", 129x, fst 7m0 now successfully because of very transparent sky, faint wisp of light with max. AP, at 129x surprisingly simple, circular 27", 113x - 419x, fst 6m5+ under bad transparency very faint glow with 113x and 293x; with 419x still visible with averted vision as a slightly concentrated glow with mottling in the background
Palomar 7 DSS 10' x 10'	Sketch (klick for enlargement)	4", 63x, fst 6m5+ at 18x not visible; visible starting with 44x; round, relativly large; can hold GC with averted vision; at the N border 11mag star; best view with 63x, more difficult to see with 88x 8" 33x, 89x, fst 7m+ with 33x round glow, easy to hold with averted vision, concentrated to its middle; with 89x still easy to see, 2 faint stars glimpsed out 16", 257x, fst 7m2 star-empty area, easy to detect, bar elongated E-W, 3 stars are resolved at the edge of the GC 27", 113x - 419x, fst 6m5+ bright glow for a Palomar Cluster, not much fainter than the neighbour cluster NGC 6539; with finder power cluster appears as a small, slightly concentrated glow directly east of a 13mag star; 419x still direct vision; unsteady background with a dozen faint stars visible as stellar peaks within
Palomar 8 DSS 10' x 10'	Sketch (klick for enlargement)	4", 88x, fst 6m5+ at 18x not visible; with 44x easy but small; best view with 88x; rich starfield; no concentation to its middle; 2 faint stars at the border; can hold GC with direct vision 12", 190x, fst 6m5+ bright and easy to detect; mottled appearance with 3-4 stars glimpsed trough the GC; a little bit concentrated to the middle; 3 brighter foreground stars around GC 15", 285x, fst 7m+ bright with mottled appearance 16", 257x, fst 7m2 rich star field, GC easy to detect, mottled appearance, a few very faint stars glimpsed trough the GC, faint stars around the globular star cluster 27", 113x-419x, fst 7m0+ bright; 12mag double star at the NW edge; GC looks granular; one dozend stars could be resolved; star clump W of the middle; not concentrated
Palomar 9 DSS 10' x 10'	Sketch 16" (klick for enlargement) Sketch 27" (klick for enlargement)	4", 126x, fst 6m5+ starting with 31x very small nebula; bright; best view with 126x; round and a little concentrated 16", 515x, fst 7m2 very small, circular, south of mag 5 star n² Sgr, with high power lots of details, brighter central part north to dominating, nearly centrically star, at NE edge of the GC another brighter area, framed from two faint stars (=Bigourdans star clump = IC 4802), at the S edge another brighter area 20", 400x, fst 7m+ GC bright, very similar detail like description with 16", star clump IC 4802 bright 27", 586x, fst 7m0+ very bright GC; star clump near the middle easy to detect; GC looks granular; two dozend stars could be resolved, most of them at the edges of the GC 27", 837x, fst 7m0+, Seeing I-II striking bright GC; with for the location (47,1°N) exeptional good seeing, the 1' large GC could be resolved in several individual stars and star clumps; background is still not fully resolved and looks various bright
Palomar 10 DSS 10' x 10'	Sketch (klick for enlargement)	15", 100x, fst 6m5 very faint, averted vision needed 16", 129x, fst 6m5 very faint, difficult to detect 16", 129x, fst 7m0 faint, large, circular, some stars are resolved at the edge of the GC, structureless 27", 172x, fst 7m+ can hold the GC with averted vision and without problems, but clearly more difficult than Pal 11 and Pal 12; round, 2' glow; diffus edges; mottled glow; 3 stars popping in and out the view
Palomar 11 DSS 10' x 10'	Sketch (klick for enlargement)	20x125, fst 6m0+ not visible 8", 47x, fst 6m5+ even with 31x a small and very faint glow is visible SE of a 9mag star; with 47x the glow is visible more easy and can be hold with averted vision; glow is not concentrated but shows some mottling without showing a star within the GC; surrounded with some faint 13mag stars 16", 257x, fst 7m2 faint, circular, also visible with higher power, 3 stars glimpsed through the halo, no other structure 20", fst 7m+ bright, can easily seen with lower magnification, with higher magnification a dozen of stars can be seen 24", fst 7m0 bright, circular, spectacular resolution into a couple of dozens of stars 27", 293x, fst 7m+ bright and remarkably glow; without an clearly concentration; with 293x a dozen stars pops out the mottled glow; brightest stars form a square figure near the middle of the GC
Palomar 12 DSS 10' x 10'	Sketch (klick for enlargement)	4", 44x, fst 6m5+ extremely difficult; near the position a close DS; above the DS a very faint nebula; can not separate the nebula from the DS; best view with 44x (AP ~2,3mm); no sure observation 16", 257x, fst 7m2 easy to detect, elongated NW-SE, 2 stars glimpsed through the GC, structureless 27", 293x, fst 7m+ bright and remarkably glow; faint concentration to the middle; 6-7 stars pops out the glow; a little bit elongated
Palomar 13 DSS 10' x 10'	Sketch (klick for enlargement)	16", 60x, fst 6m5+ under good transparency visible with averted vision; not steadily visible; slightly concentrated; no individual stars visible 16", 51x, fst 7m0+ even under perfect sky conditions hard to detect, only with max. AP (7mm), circular, structureless, neighbour of the famous S-shaped spiral galaxy NGC 7479 16", 51x, fst 7m0+ only with max. AP, faint, round, structureless glow 27", 113x, fst 6m5+ under good transparency but bad seeing easy and steadily visible with averted vision; slightly mottled with condensation to its middle 27", 293x, fst 7m0+ can hold GC with direct vision; 1,7' E a brighter 12mag star; 16mag star on the N edge; with 293x 6-7 stars glimpse out the mottled glow
Palomar 14 DSS 10' x 10'	Sketch (klick for enlargement)	16", 51x, fst 7m0 extremly difficult globular star cluster, next to Palomar 15 one of the challenging objects in the Palomar-list, very faint glow, within a triangle of mag 11 - mag 12 stars 16", 75x, fst 7m+ very faint glow around GSC 9573541; the emphasis of the glow lies in the line between GSC 9573541 and GSC 95763 at 1/3 to 9573541; round glow; relativly simple to see; can hold glow with averted vision; no concentration to its middle; only to see with 4mm AP 27", 172x, fst 7m+ with 172x a very faint but sure spot; 2' large, with 293x first stars glimps out; SW of a 14mag star
Palomar 15 DSS 10' x 10'	Sketch (klick for enlargement)	16", fst 7m0 no detection of Pal 15, small star group 3' south 16", 129x, fst 7m0 one of the most difficult globular star cluster next to Palomar 14, very dim glow, no definite observation of the GC 24", 126x, fst 7m0 even with 24" and perfect sky very difficult object, best result with AP 6mm, very faint, round glow at the accurate position, another observer confirms difficult observation 27", 172x, fst 7m+ with 172x very faint, but sure observation; could not hold it with averted vision; not stars visible; 2:3 N-S elongated with better defined W edge; 3,5' large

© DSS Bilder: Space Telescope Science Institute (California Institute of Technology, National Science Foundation, the National Geographic Society, the Sloan Foundation, the Samuel Oschin Foundation, Eastman Kodak Corporation)

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