zenithal hourly rate (ZHR) During a meteor shower, the number of meteors per hour an observer would see if his limiting magnitude (the faintest object visible) is 6.5 and the radiant is in his zenith. Since these are optimum conditions, the measured hourly rate is usually less than the ZHR. Related category METEORS AND METEORITES Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) |