Zenithal Hourly Rate

The zenithal hourly rate of the Quadrantids is approximately 130 meteors per hour at their peak; it is also a very narrow shower.

It is an annual shower associated with the Marsden group of comets that peaks on 7 June with a maximum zenithal hourly rate of 54 meteors.

Many fireballs, green-hued trails, and even some meteors that cast shadows were observed throughout the outburst, which had a maximum zenithal hourly rate of 200-300 meteors per hour.

The predictions of a shower less spectacular than the 1998 showing were borne out in a display that had a maximum zenithal hourly rate of 16-20 meteors per hour that night.

The zenithal hourly rate of this shower can be as high as two other reliably rich meteor showers, the Perseids in August and the Geminids in December.

The Sigma Arietids, a class IV meteor shower, are visible from 12 to 19 October, with a maximum zenithal hourly rate of less than two meteors per hour on 19 October.

In astronomy, the Zenithal Hourly Rate (ZHR) of a meteor shower is the number of meteors a single observer would see in one hour under a clear, dark sky (limiting apparent magnitude of 6.5) if the radiant of the shower were at the zenith.

The Andromedids were associated with the most spectacular meteor showers of the 19th century; the storms of 1872 and 1885 were estimated to have a peak rate of two meteors per second (a zenithal hourly rate of 10,000), prompting one Chinese astronomer to compare the meteors to falling rain.