Globular Clusters NGC 6544 and NGC 6553
History
These two globular clusters were discovered by William Herschel on 22 May 1784. He listed NGC 6444 as faint nebula II 197 with the notes: «Pretty bright, pretty large, irregularly round, resolvable.» NGC 6553 he listed as IV 12 with the notes: «Faint, large, irregularly round, inclining to milkyness 3 or 4' diameter, like a brush to a north preceding star, but probably unconnected.» [463]
Physical Properties
| Name | RA | Dec | Type | bMag | vMag | B-V | SB | Dim | PA | z | D(z) | MD | Dreyer Description | Identification, Remarks |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| NGC 6544 | 18 07 20.6 | -24 59 49 | GCL (V) | 7.5 | 9.2 | 3.000 | cF, pL, iR, r | WH II 197; h 1994; GC 4374; GCL 87; ESO 521-SC28 | ||||||
| NGC 6553 | 18 09 15.6 | -25 54 26 | GCL (XI) | 8.3 | 9.2 | 6.000 | globular, F, L, lE, vglbM, rr, st 20 | WH IV 12; h 3730; GC 4378; GCL 88; ESO 521-SC36 |
Finder Chart
The globular clusters NGC 6544 and 6553 are located in the constellation Sagittarius, roughly one and two degrees southeast of the gorgeous Lagoon Nebula (Messier 8). They are on 22 June in opposition to the Sun. From Switzerland it can best be seen in the months May to September.
