Detecting variables

[Martin Nicholson <newbinaries@yahoo.co.uk>]

If I were to take an image of the same part of the sky to look for new variable
stars what would be the "best" interval between pictures.

For example at this time of year it would be quite simple to take 1 image every 3
minutes for eight hours that would allow detailed lightcurves of any short period
variables in the FoV to be drawn up.

But eight hours would not be long enough to detect much change in a star with a
period of say 10 days, never mind a Mira with a period of 150 days.

How about 1, 2, 4, 8, 16 days and so on to detect longer period stars?

Any thoughts please?