(cba:news) high-speed timings of V455 And

Joe Patterson jop at astro.columbia.edu
Fri Sep 28 10:07:24 EDT 2007

Dear CBAers,

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 
be nice.

(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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