Science & Stargazing Observing Guide

Even during the absolute peak hour of a major meteor shower, sky brightness plays the most dominant factor in how many meteors you actually see. A bright moon (such as a Gibbous or Full Moon) scatters light across the atmosphere, washing out the fainter, delicate trails of meteor dust.

Our application solves this challenge by using the SunCalc astronomical model to check the exact moon phase and illuminated fraction during the peak hours of each shower. By combining this data, we rate viewing windows from Excellent (dark skies, high rates) to Poor (bright moonlight or low rate activity).

If you look up a meteor shower online, you will often see its **ZHR (Zenithal Hourly Rate)** quoted (e.g., 100 meteors per hour for the Perseids). However, ZHR is a standardized **theoretical maximum** calculated under perfect conditions:

• Perfect, crystal-clear dark skies (limiting magnitude of +6.5).
• No light pollution or moonlight whatsoever.
• The radiant point (constellation origin) is positioned directly at the zenith (overhead).

Because real-world observers rarely experience all three factors simultaneously, the actual count of visible meteors is usually lower. To give you a realistic prediction, we compute the Effective ZHR, adjusting the raw rates down based on how much light pollution the moon adds to the night sky.