Details of how the orbital lightcurve changes during the rise are of special interest. Eclipse observations should be made as frequently as photometric accuracy allows, up to one estimate per minute if an eclipse is being followed visually. The eclipse ephemeris given below should adequately predict mid-eclipse times while U Gem is at minimum light. However when an outburst begins and the light from the accretion disc becomes stronger, mid-eclipse is expected to occur earlier by up to 5 minutes compared with the ephemeris. This change is reversed at the end of an outburst.
Eclipses also become shallower on the rise to outburst and practically disappear at maximum light.
The total eclipse duration is considerably longer after an outburst than before because of the increase in radius of the accretion disc during the outburst.