The Perseids, one of the finest and the most-observed annual meteor shower peaks on August 12/13. This year the very impressive meteor shower, rich in bright trained meteors and fireballs coincides almost perfectly with the Full Moon. The bright moonlight will drown out all but the brightest of Perseids, diminishing the visual rates by 3-5 times. Still, those willing to persevere under the bright skies may be rewarded with a sprinkling of bright and colorful Perseids.
The activity graph below is updated every 15 minutes – click for details.
Perseids 2014 in detail
The Perseid meteor shower is caused by meteoroids, dust particles from the well-known, bright periodic comet 109P/Swift-Tuttle. The shower is active from mid-July to late-August, although the latest work by Molau (2013) indicates the shower may commence even earlier. It peaks on August 13 with the zenithal hourly rate usually reaching 80 – 100 meteors per hour. Under dark skies this translates to about 1 to 2 meteors per minute. This year, however, a waning gibbous Moon is high in the sky most of the peak night. The peak is expected late on August 12 to early on August 13 (Aug 12 19h UT to Aug 12 08h UT), although work by Jeremie Vaubaillon suggests the peak may occur earlier, during the second half of August 12.
Looking east at 45° N on August 13, 3:00 local time. The radiant is high in the northeast, the nearly full Moon (92% phase) is in the constellation Pisces.
Observing meteor showers under a nearly full Moon is difficult. Moonlight is scattered on haze and aerosols, producing a bright sky and greatly diminishing the number of visible meteors. By taking some additional steps, however, this effect may be mitigated to some extent. The most important step to take is to choose an observing spot at a higher elevation. Usually the most dramatic improvement occurs up to about 1500 m high, but if it is possible try to go even higher. By going above the haze the sky darkens quite dramatically and the number of visible meteor increases significantly. While observing, face away from the Moon. If possible, place it behind an object (house, tower, mountain, …). Some observers use an umbrella, to good effect. Even by taking all these steps you probably will not see nearly as many meteors as under a dark moonless sky, unless something completely unexpected happens. But strong meteor showers are fairly rare, so why not make the most of it?
Perseid radiant drift from mid July to late August. Radiant positions are marked for every 5 days.
On the peak night the radiant of the Perseids is located at the northern tip of Perseus. With 59 km/s members of this meteor shower are swift. The radiant of the shower is at its lowest early in the night and rises steadily towards the morning. Consequently the number of Perseids is the lowest in the evening hours and highest in the morning hours. This year on the peak night the Moon rises during evening twilight and is at its highest in the morning hours, somewhat diminishing the increase in the number of visible meteors by brightening the sky.
Observing the Perseids
To observe the Perseids, you need to dress warm, bring a reclining chair and watch the sky. You need no other equipment. If you decide to do so, use the IMO major meteor shower observing technique. This way your data will be in a standard format, that can readily be used for analysis. Send us your data as soon after the observations as possible.
Photographing the Perseids
If you are new to meteor photography, this shower will be somewhat more difficult due to the bright Moon. But photographing meteors is fun, and it is easy. You will need a good camera – a DSLR, a mirrorless cam or a good bridge camera will do, a tripod and a remote release. Set the aperture to a wide setting, depending on the lens you have this is usually anywhere between f/1.4 and f/3.5. Set the camera to Manual mode (M) or Bulb (B), depending on what your camera offers. You would usually go for a relatively high ISO value, but since the sky will be bright you can stay at about ISO 800 or so. Now focus the image. Focusing your camera is absolutely crucial! There are few things as frustrating as out of focus photos! Use live view to focus on a star manually. Shift the focus around until the image of the star on your screen reaches minimum size. You can also use autofocus on the Moon, but do check your first photo if it is really in focus. Then set your exposure to about 10 – 15 seconds and use the remote release to make the photo (if you do it on your camera shutter button your photos will be blurred due to camera motion). Then find the exposure you are most comfortable with – this will depend on how bright you allow the photos to be (do not go too far or any meteors will be drowned out in the bright background) and how bright your sky is.
When things go right. Jure Atanackov captured this brilliant -9 magnitude Perseid fireball in constellation Cetus on August 12, 2010 with a Nikon D80 camera set to ISO 1600 and an 18-mm f/3.5 lens (100 sec exposure). Such meteors are rare, but the excitement of catching a brilliant fireball is tremendous!