[vsnet-chat 2083] Re: Plotting light curves

[Taichi Kato <tkato>]

Re: [vsnet-chat 2082] Re: Plotting light curves

> First, there was a reason why you were taking so many frames -- sometimes
> it is because of tracking problems or saturation, but often it is to get
> high time resolution.

   From our experience with a Meade LX-200 telescope, the limitation of
exposures usually arises from the tracking problem.  We therefore use the
fixed (30 sec) exposure regardless of the magnitude (even if the object
is below 18th mag).  We can reasonably plot raw light curves of 13-14th
mag variable, but we usually have to bin if the variable is fainter than
15th mag.  Using an appropriate photometry program, stacking 100 frames
to get a single 20-th mag photometry is not a problem.

   For brighter stars (like U Gem in outburst), we sometimes use 10-sec
exposure times, resulting far more than 1000 images in a single run.
(At times, some shells and ftp wildcard expansions don't allow handling
more than 1000 files at once, causing a lengthy manual operation ;-)

Regards,
Taichi Kato

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