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