On Feb 26, 10:43 am, Anthony Ayiomamitis
wrote:
Are you aware of any "definitive"
study between the two or are we stuck with the ambiguity? Berkeley 17
has been estimated to be 10.06 or 10.08 billion years old (depending on
source) whereas NGC 6791 has estimates as high as 10.20 billion yrs old.

Looking at the follow-up articles to Salaris, there is:

Bragaglia, A. et al. 2006. BVI photometry of the very old open cluster
Berkeley 17
http://adsabs.harvard.edu/cgi-bin/np...NRAS.368.1971B

"We have obtained BVI CCD imaging of Berkeley 17, an anticentre open
cluster that competes with NGC 6791 as the oldest known open cluster."

Krusberg, Z.A.C.; Chaboyer, B. 2006. UBVI CCD Photometry of the Old
Open Cluster Berkeley 17.
http://adsabs.harvard.edu/cgi-bin/np...J....131.1565K

"Berkeley 17 and NGC 6791 are the oldest open clusters, with ages of
10 Gyr."

- Canopus56