This was received today via the Royal Astronomical Society of Canada:
Today (Friday 19 July 2013) at 5:27pm Eastern Daylight Time, the Cassini space probe in orbit around Saturn will take a picture of Saturn’s rings, backlit by the Sun. The Sun will be hidden behind Saturn, but Earth won’t be. If you want to wave at Saturn as this picture is taken, be outside at 5:27pm. It will be daylight in Ontario, but Saturn will be above the horizon. It will be about a quarter of the way up the sky, and roughly South-South East. For more information, check out http://saturn.jpl.nasa.gov/news/waveatsaturn/
Pine River Observatory’s note: Earth will be 1.44 billion kilometers from Saturn when the photo is taken. Don’t expect your face to be too clearly visible in the photo.