ZHR meaning in Academic & Science ?

In astronomy, the zenithal hourly rate (ZHR) of a meteor shower is the number of meteors a single observer would see in an hour of peak activity if it was at the zenith, assumed the conditions are excellent (stars visible up to magnitude 6,5). The rate that can effectively be seen is nearly always lower and decreases the closer the radiant is to the horizon.

The formula to calculate the ZHR is:

Z H R = H R ¯ ⋅ F ⋅ r 6.5 − l m sin ⁡ ( h R ) {\displaystyle ZHR={\cfrac {{\overline {HR}}\cdot F\cdot r^{6.5-lm}}{\sin(h_{R})}}}

where

H R ¯ = N T e f f {\displaystyle {\overline {HR}}={\cfrac {N}{T_{eff}}}}

represents the hourly rate of the observer. N is the number of meteors observed, and Teff is the effective observation time of the observer.

Example: If the observer detected 12 meteors in 15 minutes, their hourly rate was 48. (12 divided by 0.25 hours).

F = reference