Both visual and CCD observations are needed!
From AAVSO Alert Notice 332 :
Dr. Darren Baskill, University of Leicester, has requested optical observations of the cataclysmic variable star V426 Oph to coincide with upcoming XMM-Newton  observations. V426 Oph is suspected to be a magnetic cataclysmic variable  (polar). However, in previous X-Ray observations by the ASCA satellite the period modulation usually found in polars was absent. The XMM-Newton observations hope to either find the modulation or an explanation for their absense.
Intensive Observing Window:
XMM_Newton observations of this object have been scheduled as follows:
Please try to monitor this object as intensively as possible during this critical period in early March. However, observers are reminded that observations are still required from now until the end of March at least.
Light curve as of 050118: