Daytime Meteors

Space Weather News for June 5, 2009
http://spaceweather.com

DAYTIME METEORS: The annual Arietid meteor shower peaks on Sunday, June 7th. The Arietids are unusual because they are daytime meteors; they stream out of a point in the sky not far from the sun. The best time to look is just before dawn on Sunday morning when it may be possible to spot a small number of Arietids skimming the top of Earth's atmosphere. Such "Earthgrazing" meteors tend to be long, colorful, and very pretty. After daybreak, when the meteors are no longer visible to the human eye, you can listen to radar echoes from the Arietids by tuning in to our online meteor radar: http://spaceweatherradio.com .

"The Arietids are the strongest daylight shower of the year," notes Bob Lunsford of the American Meteor Society. "If you could see them through the sun's glare, you would count as many as 60 per hour. Also, don't forget that the daytime Zeta Perseids peak only two days later and are considered the second strongest daylight shower. In all my years of viewing I have never seen a Zeta Perseid, but I have seen a few Arietids. They have all been Earthgrazers and very impressive meteors."

---

Terri, Events Coordinator
Email: Events@PASAz.org
Phoenix Astronomical Society

Noctilucent Cloud Season begins

Space Weather News for May 30, 2009
http://spaceweather.com

FIRST NLCs of 2009: The first noctilucent clouds (NLCs) of 2009 have been sighted over northern Europe. Last night, May 29th, photographers recorded wispy electric-blue tendrils spreading across the twilight skies of Denmark, Northern Ireland and Scotland. This follows a similar display over Russia on May 27th. These sightings signal the beginning of the 2009 NLC season, which is expected to last until late July. Early-season NLCs are usually feeble, but these were fairly bright and vibrant, suggesting that even better displays are in the offing. Check today's edition of http://spaceweather.com for photos.

Noctilucent clouds are an unsolved puzzle. They float 83 km above Earth's surface at the edge of space itself. People first noticed NLCs in the late 19th century. In those days you had to travel to high northern latitudes to see them. In recent years, however, the clouds have been sighted in the United States as far south as Oregon, Washington and even Colorado. Climate change, space dust, and rocket launches have all been cited as possible explanations for the phenomenon. Interestingly, low solar activity seems to promote the clouds, so the ongoing deep solar minimum could set the stage for a good season in 2009.

The best time to look for NLCs is just after sunset or just before sunrise when the sun is between 6 and 16 degrees below the horizon. That's when the geometry is just right for sunlight to illuminate the tiny ice crystals that make up the clouds. Observing tips and sample photos may be found in the 2008 Noctilucent Cloud Gallery:

http://spaceweather.com/nlcs/gallery2008_page10.htm

Readers, if you enjoy these newsletters and wish to support our efforts, please consider signing up for Spaceweather.com's astronomy alert service: http://spaceweatherphone.com . Thanks!

---

Terri, Events Coordinator
Email: Events@PASAz.org
Phoenix Astronomical Society