[vsnet-chat 2626] Re: Tmz85

[Taichi Kato <tkato>]

Re: [vsnet-chat 2623] Re: Tmz85

> Just for your information. Last night, I really pushed (for the first =
> time) the limits of my telescope and CCD by following TmzV85 while it =
> was varying between mag 17 and 18.5 (unfiltered). I made 240s exposures =
> each. I know this is too long to capture the eclipses in sufficient =
> resolution, but the advantage clearly is that the S/N ratio is very =
> good.
> 
> Maybe the perfect solution is to stack exposures of 60s or so, for this =
> type of faint object.
> 
> Any experiences from other CCD photometrists ?

    In order to show how "phase-averaging" of short exposures works, I have
put a sample of averaged light curve of TmzV85 constructed from some recent
segment of time-series data.  The sampling was 0.01 phase (about 1 min, twice
our resolution); the error bars include both instrinsic variation and photon
and other noise.  This clearly shows the advantage of averaging of long
time-series of short exposures, which will not be achieved by minutes-long
exposures.

    http://ftp.kusastro.kyoto-u.ac.jp/pub/vsnet/DNe/TmzV85/phave.gif

    However hard data reduction may be, I would encourge observers to take
short exposures to eventually resolve eclipses.

Regards,
Taichi Kato

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