August 2, 2013 by ohnwentsya | Leave a comment
Perseid meteor shower: Beloved by skywatchers, 2013 will be an excellent one for the Perseid meteor shower. The moon will set before midnight on the peak Perseids nights.
By Joe Rao, Space.com / July 27, 2013
7 27 13 perseid meteor full 300
NASA Astronaut Ron Garan, Expedition 28 flight engineer, tweeted this image from the International Space Station on Sunday Aug. 14 2011 with the following caption: “What a ‘Shooting Star’ looks like from space, taken yesterday during Perseid Meteor Shower.”
(AP Photo/Ron Garan – NASA)Between Aug. 3 and 15, there are no fewer than six different active minor displays. These sixmeteor showers are listed in the table below.
The actual number of meteors a single observer can see in an hour depends strongly on sky conditions, but the only equipment you’ll need to see them are your eyes and a modest amount of patience.
The rates given in the table are based on a limited star magnitude of +6.5 (considered to be the faintest star visible to the naked eye without the use of binoculars or atelescope), an experienced observer, and an assumption that the radiant is directly overhead.
The radiant is the place in the sky where the paths of meteors, if extended backward, would intersect when plotted on a star chart. Your clenched fist held at arm’s length is equal to roughly 10 degrees on the sky. So if the radiant is 30 degrees (“three-fists”) above the horizon, the hourly rate is halved; at 15 degrees, it is one-third.
While the hourly rates from these other meteor streams provide but a fraction of the numbers produced by the Perseids, combined, overall they provide a wide variety of meteors of differing colors, speeds and trajectories. Among these are the southern Delta Aquarids, which can produce faint, medium-speed meteors; the Alpha Capricornids, described as bright yellowish meteors and the Kappa Cygnids, which sometimes produce fireballs. As such, if you stay out and watch long enough, you may be nicely rewarded for your time spent.
Note that five of the six showers listed come from the region around the constellations of Aquarius and Capricornus. Theseconstellations are highest in the southern sky between roughly 1 a. m. and 3 a.m. Eastern time. The Kappa Cygnids appear to emanate from the constellation Cygnus, which will appear more or less overhead within an hour of local midnight.
Currently, the one drawback in watching for meteors is a bright gibbous moon, which this weekend will wane to last quarter on Sunday.
As Robert Lunsford of theAmerican Meteor Societypoints out, “the waning gibbous moon will rise later during the evening hours, but will still be in the sky during the more active morning hours, causing considerable interference with meteor viewing.”
After Sunday, the moon will diminish to a crescent phase, continuing to wane in both phase and brightness and will become significantly less of a hindrance to viewers as well as rising progressively later in the night. It will be new on Aug. 5.
(The above is an excerpt. The whole article can be read at the link below)
Thanks to: http://2012spiritinaction.wordpress.com