(cba:news) VZ Scl campaign
jop at astro.columbia.edu
Sun Oct 29 11:47:54 EDT 2017
Thanks to Berto and Gordon, we are accumulating a great campaign on VZ
Scl this year... and it seems to be rewarding our efforts with deep
eclipses (as always) and superhumps (that's new). However, there are no
actual time overlaps between the two stations (Australia and South
Africa). In some years coverage from these stations can bridge the
Indian Ocean gap, but it just hasn't happened this year; and of course
we can never bridge the Atlantic plus Pacific gap!
So we need coverage from the Americas. Josch might be able to help us,
but another possibility is North American coverage. It's a challenge at
this declination, but some of our southern USA observers might be able
to handle it. Shawn or Tut, perhaps?
We can calibrate* to within ~0.06 mag even without this help, but
simultaneity of coverage reduces that error to ~0.02 mag. That would be
good. But don't mess with huge variability in airmass, because that's a
systematic error we really can't tame at all.
*BTW "calibrate" means reduce to a COMMON INSTRUMENTAL MAGNITUDE.
That's pretty much what we always seek. The more ambitious goal of
arriving at a STANDARD magnitude (Sloan, Johnson, etc.) is usually
beyond our scope... and is basically irrelevant to our goal (periodic
signal searches). Just for the record, though, our instrumental
magnitudes are usually ~0.2 mag fainter than a Johnson V. That's
assuming you report so-called "CV" magnitudes, which most of you do.
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