Tonight for July 28, 2013
Courtesy U.S. Naval Observatory
The Delta Aquarid meteor shower is predicted to be at its best during the wee hours before dawn on Monday, July 29, and Tuesday, July 30, 2013. The most favorable viewing window is from about 1 a.m. (2 a.m. Daylight Saving Time) until the onset of morning dawn. These viewing times apply to all time zones around the world. Although this shower is visible from both the Northern and Southern Hemispheres, it tends to favor the more southerly latitudes. North of the equator, it’s better seen in the tropical and subtropical regions rather than farther north. This is a long, rambling shower that’ll stretch out for weeks beyond the peak, combining with the Perseid meteor shower peak on August 11-13. So if you miss the shower tonight, keep watching!
Optimize your summer-meteor watching experience with EarthSky’s 2013 meteor guide
Just one caveat tonight, but it’s a big one. We’ll have a waning gibbous moon or last-quarter moon on the peak nights of the Delta Aquarid shower. Try your luck watching these meteors anyway, starting at late evening or around midnight – or before the moon rises into the night sky. In the Southern Hemisphere, especially, there could be a few dark hours of viewing before moonrise. The radiant for this shower climbs above the horizon at an earlier hour at more southerly latitudes – and what’s more, the moon rises later at more southerly latitudes.
The planets Jupiter, Mars and Mercury adorn the morning twilight in late July 2013. For more information on the planets, see our the EarthSky planet guide.
Unless you live in the far northern part of the globe – where there is little or no nighttime at this time of year – mid-northern latitudes can expect some viewing time before dawn, though in moonlit skies. Around the world, the planets Jupiter and Mars adorn the eastern predawn sky, and the planet Mercury rises in the east just as darkness gives way to dawn.
The Delta Aquarid shower is, at best, a modest shower, offering perhaps 15 meteors per hour. About five to ten percent of these relatively faint, medium-speed meteors leave persistent trains – glowing ionized gas trails that last a second or two after the meteor has passed.
This shower recurs annually in late July, because the Earth crosses the orbital path of Comet 96P/Machholz at this time of year. The stream of debris left behind by this comet smashes into the Earth’s upper atmosphere, to burn up in our sky as Delta Aquarid meteors.
If bright enough, you might see a meteor in the moonlight. Image credit: fraktus
If you trace the paths of the Delta Aquarid meteors backward, they all appear to radiate from a certain point in the starry heavens – near the star Delta Aquarii (Skat). This point is called the radiant of the Delta Aquarid meteor shower. As a rule of thumb, the higher the radiant point is in your sky, the more meteors that you’re likely to see. In late July, this star climbs highest up in the sky at roughly 2:30 a.m. (3:30 a.m. daylight saving time).
But you don’t have to find the radiant point of the Delta Aquarid shower to enjoy this annual celestial attraction, for these rather faint meteors streak every which way across the starry heavens on a dark, moonless light. Moonlight will undoubtedly obscure this year’s production. But if you’re game, find an open view of the sky away from pesky artificial lights, sprawl out comfortably on a reclining lawn chair, and watch these meteors streak the sky in the wee hours before dawn on Monday, July 29, and Tuesday, July 30.
Clouded out, or can’t stand the moonlight? Don’t worry. The Delta Aquarids will still be going strong when the Perseids peak a couple of weeks from now. For more, see EarthSky’s 2013 meteor guide.
These almanacs can help you find the rising time of the sun and morning planets into your sky
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Skat: Radiant for Delta Aquarid meteors
Thanks to: http://earthsky.org