The shower actually begins in late July with just a few meteors per hour, with hourly rates slowly increasing from then until the maximum, then decreasing more rapidly until the shower ends about 21 August, so in a clear dark sky you can expect to see some Perseids any time during the first 3 weeks of August. As the Moon will be less of a problem before maximum, you should see a good display late in the evenings any time from about 5-6 August onwards.
I値l also include any further info in the next email bulletin.
The Zenithal Hourly Rate (ZHR) is the rate which would be seen by an experienced observer, in a VERY dark sky, and with the radiant in the zenith: actual observed rates very rarely reach the nominal ZHR for various reasons.
Photography: If you have a digital SLR which can give longish time exposures, and you can manually focus it on infinity, and adjust it to a high ISO (film speed equivalent), you can image meteors with a bit of luck. Make a suitable lens hood, or heater, to prevent dew on the camera lens. You'll also need a long time exposure option, or a locking cable release (plus a spare one), and a tripod.
Point the camera about 50ｰ up in the sky, about 40ｰ from the radiant, for best results. Consult your camera handbook, or experiment with exposures, until the sky fogging becomes too severe.
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