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Teme - AD6IW

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MS / Quadrantid MS
«  : 03. Siječanj. 2008, 18:19:18 »

From WEB
Joe Rao Skywatching Columnist
2 hours, 45 minutes ago

The Quadrantid meteor shower is due to reach maximum in the predawn hours of Friday, Jan. 4. The Quadrantids are notoriously unpredictable, but if any year promises a fine display, this could be it.

Indeed, this may end up being the best meteor shower of 2008.

The Quadrantid (pronounced KWA-dran-tid) meteor shower provides one of the most intense annual meteor displays, with a brief, sharp maximum lasting but a few hours. The timing of peak activity favors Western Europe and eastern North America. Weather permitting, skywatchers in rural locations could see one or two shooting stars every minute during the peak.

Annual challenge

Each year, many factors combine to make the peak of this display difficult to observe. 

Peak intensity is exceedingly sharp: meteor rates exceed one-half of their highest value for only about 8-hours (compared to two days for the August Perseids).  This means that the stream of particles that produce this shower is a narrow one – apparently derived within the last 500 years from a small comet.
As viewed from mid-northern latitudes, we have to get up before dawn to see the Quadrantids at their best. This is because the radiant – that part of the sky from where the meteors to emanate – is down low on the northern horizon until about midnight, rising slowly higher as the night progresses.  The growing light of dawn ends meteor observing usually by around 7 a.m.  So, if the "Quads" are to be seen at all, some part of that 8-hour active period must fall between 2 and 7 a.m.
In one out of every three years, bright moonlight spoils the view.
Over northern latitudes, early January often sees inclement/unsettled weather.

It is not surprising then, that the Quadrantids are not as well-known as some of the other annual meteor showers, but 2008 may prove to be an unusual exception.   

Exception this year

According to the International Meteor Organization, maximum activity this year is expected on Friday 1:40 a.m. Eastern Standard Time. 

For those in the eastern United States, the radiant will be about one-quarter of the way up in the east-northeast sky.  The farther to the north and east you go, the higher in the sky the radiant will be.  To the south and west the radiant will be lower and the meteors will be fewer. 

From Western Europe, the radiant will soar high in the east as the peak arrives just as morning twilight intervenes.

Quadrantid meteors are described as bright and bluish with long silvery trains.  Some years produce a mere handful, but for favorably placed observers, this could be a shower to remember; at greatest activity, Quadrantid rates will likely range from 30 to 60 per hour for eastern parts of the U.S. and Canada, to 60 to 120 per hour for Western Europe. 

Across central and western parts of North America, the shower's sharp peak will have already passed and meteor activity will be rapidly diminishing by the time the radiant has a chance to get very high in the northeastern sky.  Nonetheless, hourly rates of perhaps 15 to 30 may still be seen. 

The moon will be a waning crescent, not rising until after 4 a.m. and will add very little light to the sky


Goran AD6IW

Prodam / prodajem 70cm linear pa 2x 4cx250b 800W
«  : 30. Svibanj. 2007, 18:57:30 »
Veoma povoljno prodajem linearno pojacalo za 432MHz, sa 2 x 4cx 250b, zajedno sa ispravljacem,
bez antenskog releja, koristen za EME. Duze vremena pojacivac nije koristen, preporucen je
servis. Prilikom kupnje potrebno je da se licno pruzme u Crikvenici.
Ponude i upite slati na:

73 AD6IW

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