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(meteorobs) NEAR mission
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To: bpeck@alohadot net, fritz@hawaiidot edu, wrathalj@byuhdot edu, 102142.3165@compuserve.com, calef@lavadot net, prb@lavadot net, eide@hawaiidot edu, witokazu@bishop.bishop.hawaii.org, giguere@watt.pgd.hawaiidot edu, reward@hialohadot net, meteorobs@latrade.com, meisel@uno.cc.geneseodot edu
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Subject: (meteorobs) NEAR mission
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From: Jim Bedient <wh6ef@pixi.com>
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Date: Sat, 17 Jan 1998 23:41:54 -1000
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Reply-To: meteorobs@latrade.com
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Sender: owner-meteorobs
From: David Dunham (dunham@erols.com)
Subject: NEAR spacecraft to shine brightly Thurs. night
Spacecraft to shine brightly Thursday night
On Thursday night-Friday morning, January 22-23, the Near Earth
Asteroid Rendezvous (NEAR) spacecraft will swing by the Earth
primarily to change its orbital plane to match that of the asteroid
433 Eros, NEAR's target for an early 1999 rendezvous. As NEAR
approaches the Earth, its almost 100 square feet of solar panels
will be rotated to reflect sunlight to several regions of the
U.S.A., providing a unique opportunity to see with the naked eye an
interplanetary spacecraft flying through space. Although NEAR will
be about 9000 miles over the North Pacific Ocean at the time, it is
expected to briefly shine as bright as Capella, among the brightest
stars in the sky. These NEAR sunglints will be visible from 1:25 am
to 1:49 am EST January 23rd (10:25 pm to 10:49 pm PST January 22nd),
about an hour before NEAR's closest approach to the Earth over 300
miles above the Middle East. More about NEAR's Earth swingby is
available in a press release from the Johns Hopkins University's
Applied Physics Laboratory (APL) available on the Web at
http://www.jhuapldot edu/public/pr/swing.htm
This site lists the following times to see the sunglint:
Areas Most Likely to See NEAR's Sunglint:
Region (Friday Jan. 23) Sunglint Time
s. New England, e. New York* 1:25 am EST
Midwest (s. Ontario, Detroit area) 1:26 am EST
Midwest (Chicago & Kans. City areas) 12:26 am CST
s. Nebr., n. Missouri, central Illinois 12:28 am CST
s. Indiana, Cincinnati, W. Va. 1:28 am EST
e. Virginia, DC area, Md., s. Penn.* 1:29 am EST
Central Va., central N. Car., S. Car. 1:30 am EST
Georgia, central & e. Tenn.* 1:31 am EST
Georgia (again), Florida peninsula 1:32 am EST
Florida peninsula (again)* 1:33 am EST
Louisiana* 12:35 am CST
eastern Texas* 12:37 am CST
San Angelo to Midland-Odessa, Texas 12:39 am CST
Region (Thursday Jan. 22) Sunglint Time
Colorado* 11:27 pm MST
s. New Mexico, s. Arizona 11:39 pm MST
southern California* 10:40 pm PST
southern Nevada 10:41 pm PST
Utah* 11:41 pm MST
central Calif. (Fresno area) 10:43 pm PST
n. Calif. (San Francisco-Sacramento)* 10:44 pm PST
Oregon 10:45 pm PST
w. Washington state, s.w. Brit. Col.* 10:46 pm PST
Oahu and Maui, Hawaii* 8:48 pm HST
*These are "targeted" regions that will see the flash for about half
a minute. Other areas will see the flash for only a few seconds.
Watch for about three minutes, starting a minute before the listed
time.
The press release also describes approximately how to find NEAR:
If you are in one of the sunglint regions listed above, look for the
brightest star above the northwestern horizon, Capella, which will
be about halfway between the horizon and straight overhead for the
East Coast, and higher on the West Coast. Hold your hand at arm's
length and stretch out your fingers, putting the end of your little
finger at the top at Capella. The tip of your thumb, pointing
straight down from Capella, will mark the approximate location where
the sunglint will occur in the constellation Perseus, about 20
degrees below Capella. The glint should be very noticeable, about
as bright as Capella. The press release Web site includes a figure
illustrating this.
Hawaii will see the brightest flash, as bright as Sirius, the
brightest star in the night sky. The view there will differ from
other parts of the U.S., with Capella being above the northern
horizon and the glint being below and to the left of Capella.
Sky charts for locating the glint areas with binoculars and a map
showing the path of the glint zone (100 to 200 miles wide, depending
on the geometry) will soon be on IOTA's Web sites at
http://www.skydot net/~robinson/iotandx.htm and
http://www.anomalies.com/iota/splash.htm
The U.S.A. map showing the path has no times; use the table above
for the time for your location. A version of the map with Universal
Times will be posted on the IOTA sites either late tonight or
tomorrow. A local-time version will be posted either tomorrow or
Monday, with the best-quality version being posted Monday at the
NEAR Web site. Two sky charts are posted, one calculated for the
Washington-Baltimore area but which can be used for the eastern half
of the U.S.A., and one for Los Angeles that will be good enough for
the western half of the country. Similar charts for about a dozen
other locations will be posted Monday or Tuesday probably at the
NEAR site but possibly at the IOTA sites. Anyone needing a
preliminary version of one of these charts for other regions for
publication can contact me to obtain it by fax.
An animation showing the path of the sunglint can be found on the
NEAR Web site: http://sd-www.jhuapldot edu/NEAR/
That site also includes a chart of Perseus showing in more detail
where the sunglint will appear for different cities, suitable for
those who want to find the sunglint location with powerful
binoculars or telescopes. That site indicates that it might be
best to see the sunglint with a telescope, but that is misleading;
it will be easy to see with the naked eye.
NEAR's pointing should be accurate to better than 0.1 deg., less
than a fifth of the diameter of the Sun. But the solar panels could
be misaligned with the spacecraft axis by a few tenths of a degree,
and (unlikely) even as much as a degree. So observers at least half
a pathwidth (and maybe more) outside of the predicted path have a
chance to see at least part of the sunglint. It may occur in steps
since NEAR has 4 solar panel arrays, each of which might be
misaligned a little relative to each other.
Timed observations of the sunglint are sought to try to measure the
solar panel alignments precisely. Such observations could be made
with a camcorder (use manual focus), or visually with a tape
recorder, like timing a grazing or asteroidal occultation. Record
WWV shortwave time signals along with the event for timing. More
about recording and reporting the sunglint will be distributed later
and posted on the IOTA Web sites.
David Dunham, IOTA and NEAR Mission Design January 17, 1998
Telephones: 301-474-4722 at home and 301-953-5609 at APL
E-mail: dunham@erols.com at home and David.Dunham@jhuapldot edu at APL
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|James R. Bedient |E-Mail: jamesdot bedient@faa.dotdot gov|
|Traffic Management Coordinator | Fax: 808-739-7604 |
|Federal Aviation Administration| Home: wh6ef@pixi.com |
|Honolulu CERAP |School: jamesbed@hawaiidot edu |
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