10 cm apertures

[<aah@nofs.navy.mil>]

I was reducing some data from ARNE, and it reminded
me of how much photometry has changed.  Back in the
1970's I was using a 40cm telescope with a 1P21
photoelectric photometer to do a survey of short-period
cepheids.  With that setup, I could work down to
about V=12.5 before it became too difficult to center
the star in the aperture, and the integration times
got too long to ensure a good measure before offsetting
to the comparison star.
  I just measured a variable at V=12 with a 60-second
exposure with ARNE, getting about the same accuracy
I was getting with the 40cm system with 10x longer
integrations.  Plus, I measured 3500 other stars
at the same time, and did it during non-photometric
conditions.
Arne