The following is a list of celestial events occurring in August 2009.
- August 5 - Penumbral lunar eclispe centered at 00:39 UTC.
- August 6 - Jupiter is 3 degrees south of the Moon.
- August 12 - The Perseid meteor shower peaks at 18:00 UTC. The Perseids are expected to produce up to 100 meteors per hour this year. This is definitely a meteor shower you won't want to miss!
- August 14 - Jupiter is at opposition at 18:00 UTC. This is the best time to view Jupiter, as it is the closest Earth will approach the planet. Thus, Jupiter will appear its largest and brightest that it will all year.
- August 17 - Neptune is at opposition at 21:00 UTC. If you're going to look for Neptune, this is definitely the time to do so.
- August 19 - Double Galilean shadow transit occurs at 23:47 UTC.
- August 24 - Mercury is at its greatest eastern elongation at 16:00 UTC. This is the time at which the planet will appear furthest from the Sun from our point of view. This is one of the best times to observe Mercury; just be careful that the Sun is not in the telescope's field of view.
- August 27 - Double Galilean shadow transit begins at 02:42 UTC.