Hi All,
Starting back in the 1960's (?) Alan Cousins and others in South African used photoelectric photometry to establish the UBV(RI)c standards in the Harvard E Regions. Does anyone know what the photometer entrance aperture size was in arcseconds? Cheers,
Mark Blackford
good morning Mark.
I worked last year with several documents of that time drifting cumulus magnitudes for M 7and NGC 6530, and if I remember correctly, they used 15 ", I keep those papers in the PC, this are the address of two of them.
http://articles.adsabs.harvard.edu/full/1957ApJ...125..636W
http://articles.adsabs.harvard.edu/full/1959BAN....14..265K
As they say there, and more references samples.
Hi Mark,
The E-region observations were done using a 40-arcsec aperture. Here is one of Cousins' papers that actually mentions the aperture size:
http://articles.adsabs.harvard.edu/full/1983SAAOC...7...36C
Such a large aperture (today's standards) was acceptable because these are all bright stars.
Arne
Hi Oliver and Arne,
thanks for the references. Cheers,
Mark