Dátum: 1999. február 4., 17:39
Feladó:
Tárgy: MIR
Ez meg az AAVSO listan jott. Itt mar a MIR-t is emlitik...
>Date: Thu, 4 Feb 1999 14:34:42 GMT
>From: Ron Baalke
>To:
>Subject: [ASTRO] Russian Space Mirror To Be Tested
>
>
> SKY & TELESCOPE's ELECTRONIC NEWS BULLETIN
> Special Edition: February 2, 1999
>
>RUSSIAN SPACE MIRROR TO BE TESTED THURSDAY
EVENING
>
>An unusual and potentially very bright light will shine in the evening
sky
>over parts of North America and Europe this Thursday. That's
when Russian
>space officials say their Znamya 2.5 space mirror will be deployed
and
>tested by orbiting cosmonauts aboard the Mir space station.
Future versions
>of the satellite could someday shorten the long winter nights of
>far-northern cities -- much to the chagrin of backyard skygazers.
>
>The Znamya experiment calls for bouncing sunlight off a circular,
25-meter
>(80-foot) reflector and directing the light toward several cities in
Europe
>and North America after sunset on February 4th. The light beam
will be an
>estimated 5-7 kilometers (3-4 miles) wide. If the experiment
succeeds,
>areas along the ground track could be bathed in light five to 10
times
>brighter than the full Moon for a few seconds to a few minutes.
Cosmonauts
>Gennady Padalka and Sergei Avdeyev will orient the reflector by
remote
>control, attempting to keep it trained on ground targets for one or
two
>minutes at a time. Observers outside Znamya 2.5's directed beam
could see
>the spacecraft outshining virtually every star as it coasts across
the sky
>in an orbit 360 km (225 miles) high.
>
>Amateur astronomers in the targeted cities or living along the
ground track
>will be well positioned to estimate the brightness of Znamya's
reflected
>beam of sunlight. According to SKY & TELESCOPE magazine,
observers near the
>ground track will see Znamya and Mir appear as a bright, slowly
moving
>"double star." Only if the beam passes directly over your location
will
>Znamya flare to full-Moon brilliance, and then only if the sky is
clear.
>Observers under cloudy skies may see the clouds brighten as if
illuminated
>from within by lightning.
>
>"Most people don't realize you can see orbiting satellites from the
>ground," says J. Kelly Beatty, SKY & TELESCOPE's senior
editor. "Most are
>quite faint and go unnoticed," he adds, "but this one could get so
bright
>it will be impossible to miss. Those who aren't expecting it may
think
>they've spotted a UFO."
>
>Details about Znamya (Russian for "banner") are reported in SKY
&
>TELESCOPE's February issue and on its Web site
(www.skypub.com). This Web
>site also offers Mir visibility predictions for 100 cities in North
America
>and 100 other cities worldwide.
>
>Here is the February 4th timetable released last weekend by
officials of
>the Space Regatta Consortium (SRC), which is funding the
Znamya test. Note
>that times are approximate and may change a little, depending on
Mir's
>exact orbit at the time of deployment. (* = February 5th)
>
> UT Local time
> (GMT) on Feb 4th Event
>
> 10:04 Progress M-40 undocks from Mir
> 11:34 Znamya 2.5 reflector deploys from Progress
> 13:12 6:12 pm light beam on Karaganda, Kazakhstan
> 14:45 5:45 pm light beam on Saratov, Russia
> 16:20 7:20 pm light beam on Poltava, Ukraine
> 17:54 6:54 pm light beam on Liege, Belgium
> 17:56 6:56 pm light beam on Frankfurt, Germany
> 23:54 5:54 pm light beam on Winnipeg, Manitoba
> 23:56 6:56 pm light beam on Quebec City, Quebec
> 1:30* 6:30 pm light beam on Calgary, Alberta
> 1:32* 7:32 pm light beam on Devil's Lake, North Dakota
> 2:13* Test ends, reflector is released
>
>SRC is a partnership involving seven Russian aerospace
management and
>engineering organizations. They eventually hope to loft whole
>constellations of space mirrors orbiting 1,500 to 4,500 km (930 to
2,800
>miles) high. With a diameter of 200 meters (650 feet), each
satellite could
>beam down a disk of light as wide as a city and up to 100 times
the full
>Moon's brightness. These cosmic klieg lights could be used to
illuminate
>high-latitude regions of Earth in the hours after sunset or before
sunrise,
>ostensibly to improve the spirits and productivity of those forced
to
>endure long, dark winters. But the prospect of an armada of giant
space
>mirrors has astronomers worried that our view of the starry sky will
be
>spoiled by light pollution from the satellites. "The best way to
assess the
>seriousness of this threat," says SKY & TELESCOPE's Beatty, "is
for lots of
>experienced skygazers both within and outside the ground track to
watch for
>Znamya on Thursday evening and estimate how bright it actually
gets."
>Observing reports may be e-mailed to SKY & TELESCOPE at
>
>On February 4, 1993, SRC conducted an orbital test of a slightly
smaller
>reflector called Znamya 2. The spinning space mirror directed a 4-
km-wide
>(2.5-mile) spot of reflected sunlight along a swath of Europe that
lay in
>predawn darkness. Although much of the target area was
blanketed by clouds,
>a few observers reported seeing a 1-second-long flash nearly as
bright as
>the full Moon.
>
> ###
>
>Additional information is available on SKY & TELESCOPE's Web
site at
> http://www.skypub.com/news/special/znamya.html
>
>
>
>
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