Palomar globular star clusters

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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 18 10 44.3 -07 12 27 Ser 7.1' 126
8 18 41 29.9 -19 49 33 Sgr 4.7' 145
9 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
 
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

 

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
 

Palomar 5

DSS 10' x 10'

Sketch (klick for enlargement)

16", 51x, fst 6m5
first try together with Martin Schoenball, we both see somewhat faint but in wrong position, negative observation

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

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
 

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
 

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
 

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 (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 n 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
 

Palomar 10

DSS 10' x 10'

Sketch (klick for enlargement)

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)

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", 51x, fst 7m2
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 7m2
only with max. AP, faint, round, structureless glow

27", 293x, fst 7m+
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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