(cba:news) high-speed timings of V455 And
jop at astro.columbia.edu
Fri Sep 28 10:07:24 EDT 2007
So it appears that many of us will be doing faster-than-usual photometry
in the next few weeks. Here are some things to bear in mind:
(1) make the cycle time (integration+dead) less than 0.5 x the shortest
period you suspect might be present. For this star, we know of a signal
at 34 s (the harmonic of the 68 s fundamental, but with a fine structure
that conveys some extra information in itself)... so "under 15 s" would
(2) report times as "mid-integration" - not "mid-cycle", or
"start-exposure", or anything else that might seem logical.
(3) report times to 5 places (after the decimal).
(4) check computer clock against wwv to insure accuracy. we seek
accuracy to +-1 second; +-2 is tolerable... above that, well, only if
your data are lousy anyway!
(5) use JD, not HJD, BJD, MJD, or any other convention.
In practice, the short-exposure (i.e. short cycle-time) requirement
might prove to be a problem after the star fades some more. MOST of the
information is at the 68 s fundamental; so cycle times around 25 s or
so, which appear to be convenient for most of you, will be OK.
Nevertheless, shorter cycle times always give you a broader net for
catching things you didn't expect!
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