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От: Joan and David Dunham
Тема: Need publicity for Aldebaran occ'n, Orient, Oct. 9
Дата: 5 октября 1998 г. 12:26

Publicity and Coordinators needed for Oct. 9th Aldebaran Occultation
in the Orient

I wrote the message below for a good occultation of Aldebaran a
month earlier visible from the eastern U.S.A. on September 12th; I have
revised it for possible use for the October 9th occultation that will be
visible from the most populous parts of the Far East, including Japan,
Korea, the Philippines, and most of eastern China. Please do what you
can to get help from others to encourage observation of this month's
occultation throughout your country.

*********************************************************************

Local and Regional Coordinators, and OBSERVERS are needed for Friday
night's spectacular Aldebaran Occultation and Graze

Aldebaran is the brightest star, other than the Sun, that can be
occulted by the Moon. Time is short, but please try to make the most of
this opportunity, not only for obtaining science but for public
outreach. Local coordinators are critical for public participation to
obtain unpreceded large quantities of accurate timings of the
occultation, now that we know that national broadcasts via cable can't
be used for accurate timing. Much information about the occultation is
on IOTA's Web site at http://www.sky.net/~robinson/iotandx.htm - please
visit it. Tasks that might be undertaken are described below.

1. Use your camcorder (or a borrowed camcorder) to record a strong local
television station. Record the selected station along with JJY time
signals to create a master tape for your area. It must be an "over-the-
air" broadcast, not a cable version of it. This is because the cable
network uses geosynchronous satellites for distribution, and even in the
same area, there can be different numbers of "hops" to and from the
satellites, causeing unknown delays in the signal in different
neighborhoods. So if you have cable, don't use it for this job; get out
a rabbit ear antenna, if you have one. The quality of the image is not
important as long as you can distinguish when scene changes occur. The
recording should cover from ten minutes before to ten minutes after the
reappearance in your area. Also record for the disappearance if you
know of other observers who will be recording the occultation with
camcorders pointed into the eyepiece of their telescope, but who don't
have JJY receivers. You will probably want to record the occultation
with the camcorder yourself, leaving a few minute gap in the coverage.
If so, just make an ordinary VCR recording of the TV broadcast (THAT can
even be cable), or arrange for someone else to do so. It can be used as
the master tape after two or three points (broadcast scene changes) from
your camcorder/JJY recording of the station are timed accurately. JJY
or WWVH are preferred for determination of Coordinated Universal Time
on the tapes. Let your national coordinator know if you can make such a
master tape in your area so that the information about it can be posted
on a Web site frequented by observers, and otherwise further distributed
[for example, on September 12th, we distributed a simple message about
the event, refering to IOTA's Web site for charts, to all employees of a
few institutions in Maryland]. If it's inconvenient for you to do this
job, try to find someone else, perhaps an amateur radio operator, who
might be able to perform the task. If this task can not be performed,
then observers with JJY receivers, Arcron clocks, or other sources of
accurate time can be encouraged to observe. If this task will be
undertaken, proceed with the other tasks below.

2. Encourage other amateur astronomers, and other friends and
relatives in the region of visibility to record the occultation with
camcorders. Try to borrow one if you don't own one.

3. Spread word about the occultation via bulletin boards and e-mail;
you might get permission to distribute information at your office or
school. For example, information about the occultation might be
distributed widely in schools.

4. Contact Local Newspapers and TV Stations to inform them of the
event, and the need for camcorder observations. Use the sample local
press release below for this [you need to fill in the blanks about the
local TV broadcast that should be used]. Prepare a local moonview
showing the path of the Moon behind the Moon for your location; it can
be very simple and does not need to be accurate for camcorder and
binocular obervers who will see the whole Moon, anyway.

5. Encourage those with telescopes to use it with a camcorder to
record the disappearance, as well as the reappearance without the
telescope (in the scope, the R may be difficult to locate).

6. A dark-limb graze of such a bright star is a rare treat; gradual
events revealing the star's angular diameter will be noticeable, one of
the few cases where this is true even with binoculars. Information
about the northern-limit graze crossing northern China and the Russian
Far East is given separately on IOTA's Web site.

7. Collect videotapes of the occultation made in your region.

David W. Dunham, IOTA email: dunham@erols.com phone: 301-474-4722
Office: fax 240-228-1093 david.dunham@jhuapl.edu 240-228-5609

P.S. A general press release about the occultation might be distributed
to several newspapers and television stations in the region of
visibility, but LOCAL releases specifying a TV station that can be used
locally for timing will be more effective.

****** A sample local press release is belew ******
Items that you need to complete are in [ ]

Naked-Eye Eclipse of Bright Star Friday Night, October 9th

Astronomers need your camcorder records
for lunar and solar (Earth climate) studies

Late Friday night, October 9th, the bright orange star Aldebaran
will be eclipsed by the waning gibbous Moon. The reappearance on the
dark side of the Moon will be easy to see with the naked eye throughout
[your coutry or region]. This event is called an "occultation" by
astronomers. The figure below shows what the occultation will look like
in [your region]. But you only need to look near the top of the
Moon, on its dark side, to locate the bright star when it blazes back
into view from behind the retreating edge of the Moon. The star might be
seen several minutes before it disappears. But Aldebaran will be harder
to see then in the glare of the nearby sunlit part of the Moon. The
bright part of the Moon will overwhelm the star a minute or more before
the disappearance, which might be seen only with the help of binoculars
or a small telescope.

[This space is for the Moon view for your city; add enough blank lines]

In [your region], the occultation can be videotaped by anyone with a
camcorder. We will accurately time the broadcast of Xxxx, Channel #
[specify the station and channel], and encourage as many camcorder
owners as possible to record this rare event, as well as Xxxx before and
after the reappearance to provide an accurate time base. Recordings from
many locations will allow the edge of the Moon to be mapped in
unprecedented detail, with more accuracy than was obtained with the
Clementine lunar orbiter in 1994, reducing the current largest source of
error for analysis of past solar eclipse timings. These solar eclipse
observations in turn are used to measure small but climactically
significant variations of the solar diameter, possibly shedding light on
the controversy of how much the current global warming trend is due to
increased buring of fossil fuels and how much of it is due to natural
variations of the Sun. But the use of solar eclipse timings for this
purpose is now limited by our knowledge of the lunar topography.

The time of the occultation varies by several minutes across the
[specify your] region. [Give the event times for a few surrounding
cities, or possibly a map showing equal time lines, if you can generate
such maps, which we prepared for the September 12th event].

Camcorder users should do the following:

1. Set your alarm to wake up at least 20 minutes before the
reappearance, or stay up for it. You might want to get up earlier
to see Aldebaran before it disappears.

2. Five minutes before the reappearance, turn on your camcorder and
record a minute of Xxxx. It is important that you use an ordinary
"over the air" broadcast and not a cable version, since cable
systems introduce unknown time delays in different localities.

3. Keeping the camcorder recording, go outside and record the Moon,
zooming in on it and maintaining a good focus. Use of manual focus
might help.

4. Just after Aldebaran reappears, go back to your TV and record another
minute of Xxxx, with the camcorder running the whole time.

5. Turn off the camcorder. If successful, send the tape to [give your
name and address, or that of an IOTA coordinator for your region].
Enclose with the tape a diagram showing about how far you were from
the center of the nearest street, and then the distance along the
street to the center of the nearest intersecting street. You can
just pace the distances; we need an accuracy of about 10 feet.

If your camcorder has an electronic "anti-shake" feature, turn it off.
It delays the video signal relative to the audio signal, degrading
timing accuracy. If your camcorder has a time display including seconds,
keep it running throughout. If you have a shortwave radio, please also
record JJY time signals at 5.0 or 10.0 megahertz during the observation.
Any observations that you can provide will be greatly appreciated.

[Include this paragraph only if your city is within about 200
miles of the northern limit] Within a mile or two of the northern limit
graze line shown on the map [if you prepare one], the star will just
graze the northern edge of the Moon, disappearing and reappearing
several times among the lunar mountains and craters. "X" marks the
approximate location of expeditions that are planned to record this
spectacular graze. Anyone who lives within, or can travel to, the
narrow graze zone can see this interesting phenomenon with binoculars or
possibly with the naked eye if most of the bright part of the Moon can
be blocked from view.

Aldebaran is the brightest star, other than the Sun, that the
Moon can eclipse.

IOTA Web site for more information: http://www.sky.net/~robinson/iotandx.htm

[your name], October X, 1998

**********************************************************************

On September 12th, we had mixed success, mainly due to clouds that
covered the areas where the publicity was best. Nevertheless, we did
receive a few useful videotapes from the public, and over 100 contacts
were timed by about 30 observers in seven expeditions.

On October 19th last year, I used a 12x camcorder to record the
disappearance of Aldebaran on the bright side of the Moon with my
telescope. Then I used the camcorder directly to record the
reappearance on the dark side with the Moon 86% sunlit; it worked well.
Mitsuru Soma at the Japanese National Observatory, e-mail
somamt@cc.nao.ac.jp, has a copy of that videotape.

David Dunham, IOTA, dunham@erols.com, 1998 October 4