HP 1, BH 229

Globular Cluster HP 1 (Dufay 1, BH 229), in Ophiuchus

RA:
17:31:05.2
Dec:
-29:58:54
Distance from Sun:
26.7 kly
Distance from Galactic Center:
1.6 kly
Apparent Diameter:
8.2 arc min
Brightness:
11.59 mag vis
Radial Velocity:
+55.7 +/- 0.7 km/s
Diameter:
ly
Abs. Mag:
-6.46 Mag vis
Discovered by Dufay, Berthier and Morignat in 1954.
Independently rediscovered by van den Bergh and Hagen in 1975.

Globular Cluster HP 1 was discovered by Dufay et.al. (1954), and sometimes referred to as "HP" for the Haute-Provence Observatory where the discovery occurred (e.g., Sawyer Hogg 1959). This designation was mutated to HP 1 as more globular clusters were discovered at that observatory in the 1960s by Terzan. It is also referred to as Dufay 1 for his discoverer.

There is some dispute on the cluster's distance: Longly, it was thought that HP 1 is situated close to the Galactic Center (GC), 26.7 kly from us and 1.6 kly from GC, but later estimates have put it as far as about 20,000 light years beyond, to a total distance of 46,000 light years from us. New estimates again have it closer to the Galactic Center, at 22,800 ly from us and 4,100 ly from the Galactic Center (Baumgardt 2023).

References:

[MW Globulars] | [DSS] | [SIMBAD] | [ADS] | [GGC-DB]
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