Ruprecht 106 Globular Cluster

[Allan]

I observed this globular cluster during the last new moon window. I spent a year researching Milky Way globular clusters and have started on my way to observe and note all 168 on my list.

Ruprecht 106 is in Centaurus, and being in the deep south, only open to us southerners for observation. I observed this in the 32", and am sure it will take at least moderate aperture to see. Wondering if anyone else has ever observed this cluster?

My notes read -

At 310x, 387x. A large and obvious yet low surface brightness glow. Numerous faint (magnitude 17) stars are resolved throughout the cluster with a clump of about one dozen on the NE edge. Many bright foreground stars cross the face of the cluster, with a magnitude 8.4 foreground star 4' to the SE.

[ngcles]

Hi Allan,

Here are a couple of observing notes from over the years using 25cm and 46cm aperture:

Ruprecht 106 GC Centaurus
25cm x86: Not a particularly difficult object. Found in a field of nearly innumerable stars, 2 degrees S of Gamma Centauri. Appears as an unresolved fairly sizable milky glow perhaps 2.5' diameter. Seems to have several faint, apparently superimposition stars about magnitude 14. magnitude8.5 star to the S by 4'. The field is littered with scattered magnitude 13-14 stars like the sands of the beach.

46cm x185: This cluster is quite close to a magnitude 9 star, 3' away to the S as a quite diffuse, hazy, galaxy-like looking object perhaps 2.0 -2.5' diameter with several faint stars scattered over the top. These may be resolved stars but are just as likely field stars at about magnitude 14. Appears to brighten broadly and slightly to centre without core or pip, 3' diameter hazy, background does not seem granular. Profusely littered field.

Best,

L.

[Allan]

They are good notes. Yours match mine quite well in their description. You describe it as not difficult in your 25cm, so I presume lots of people must have observed this one.

[glend (Glen)]

Interesting area as all the nine major stars appear to be "original" hydrogen stars, making this a "single population cluster" based on this study:

https://arxiv.org/abs/1310.5900

I had a look at the CDS Portal page, here:

http://cdsportal.u-strasbg.fr/?target=C%201235-509

I doubt I have the aperture any longer to have a serious look, but next time I am looking out that way I will check out the location. Now I wish I kept the 16".
Thanks Allan, and Les.