Astronomy Department,
Columbia University, New York, NY 10027
Received: December 5,
1991
Abstract
Recent interest in long
periods which may be present in cataclysmic variables has been motivated
principally by the idea that solar-like magnetic cycles might be
important.For the brighter
members of the class, AAVSO light curves are an ideal resource for testing the
presence of such periods.The
detection limits are much more sensitive than could be acheived by any feasible
photographic or photoelectric means.But, artifacts are found to be present in the Fourier spectra of the
light curves of novae, caused by the lunar synodic period, the lunar sidereal
period, the Earth's rotation period, and the round-off errors made by observers
in recording the time.