Next live webcast: Total Lunar Eclipse of February 20-21, 2008

MAY 4, 2004

  • Lunar Eclipse Gallery, May 4-5, 2004

    On Tuesday 4 May 2004 (Wednesday 5 May in Australia and Asia), the full Moon passed through the Earth's shadow, producing a total lunar eclipse for skywatchers throughout Asia, Australia, Europe, Africa and South America. In The Netherlands and Belgium Astronet and Kennislink ("Knowledge Link") in cooperation with the Dutch Copernicus Public Observatory and Belgian Mira Public Observatory organized a live webcast of the event.


    Archive image of webcast by
    Copernicus Public Obervatory, Netherlands

    Archive images by
    Mira Public Obervatory, Belgium

    Other live webcasts:

  • Saros: LIVE BROADCAST 19:30 UT. Total Lunar Eclipse, Mirror 1 (Gran Canaria, Canary Isles)
  • Saros: LIVE BROADCAST 19:30 UT. Total Lunar Eclipse, Mirror 2 (Gran Canaria, Canary Isles)
  • Observatorio, Universidad Complutense de Madrid (UCM): Eclipse Total de Luna (4 Mayo 2004) (Madrid, Spain)
  • Planetario de Madrid: Observación del eclipse total de luna del 4 de Mayo de 2004(Madrid, Spain)
  • Universitat de Barcelona: Welcome to this lunar eclipse (Barcelona, Spain)
  • Agrupación Astronómica de Sabadell: Eclipse Total de Luna (Sabadell, Spain)
  • Blue Hyppo/PUSKAL-Sabah: Total Lunar Eclipse (Sabah, Malaysia)
  • ParsSky: Live Broadcast of Lunar Eclipse from Iran (Esfahan, Iran)
  • Nojum, the astronomy magazine of Iran: May 4th Lunar Eclipse (Tehran, Iran)


    Copper Moon

    A lunar eclipse occurs when the Full Moon passes through the Earth's shadow.

    The Moon encounters the penumbra, the Earth's outermost shadow zone, at 17:51 Universal Time (UT). About thirty minutes later a slight dusky shading can be noticed on the leading edge of the Moon.

    At 18:48 UT the Moon begins its entry into the innermost shadow zone, or umbra. For more than an hour a circular shadow creeps across the Moon's face. At 19:52 UT, the Moon will lie completely within Earth's dark shadow. It will then take on an eerie coppery tint that has often been compared with blood.

    During a total eclipse the Moon shines with a orange reddish glow
    Photograph: Robert Smallegange (Leeuwarden, The Netherlands)

    Without Earth's atmosphere, the Moon would disappear completely once immersed in the umbra. Longer wavelengths of light penetrate Earth's atmosphere better than shorter wavelengths, which is why the rising or setting sun looks reddish. In essence, the ruddy tint of a totally eclipsed moon comes from the ring of atmosphere around Earth's limb that scatters a sunset-like glow into the umbra.

    During totality a ring of reddish sunlight surrounds the Earth
    Courtesy: Francis Reddy.

    The hue actually changes from one eclipse to another, ranging from a bright coppery orange to brownish. The Moon may darken so much that it becomes all but invisible to the unaided eye. These very dark lunar eclipses often occur after exceptional volcanic eruptions.

    Totality will end at 21:08 UT, when the moon's leading edge exits the umbra. The moon will leave the umbra completely at 22:12 UT, and the eclipse will end at 23:10 UT when the moon makes its last contact with the penumbra.

    Path of the Moon through Earth's umbral
    and penumbral shadows during the Total
    Lunar Eclipse of May 4, 2004.

    Courtesy: Fred Espenak

    Crater timings

    In 1702, Pierre de La Hire made a curious observation about Earth's umbra. In order to accurately predict the duration of a lunar eclipse, he found it necessary to increase the radius of the shadow about 2% larger than warranted by geometric considerations. Although the effect is clearly related to Earth's atmosphere, it's not completely understood since the shadow enlargement seems to vary from one eclipse to the next. The enlargement can be measured through careful timings of lunar craters as they enter and exit the umbra. Such observations are best made using a low-power telescope and a clock or watch synchronized with radio time signals. Timings should be made to a precision of 0.1 minute. The basic idea is to record the instant when the most abrupt gradient at the umbra's edge crosses the apparent centre of the crater. In the case of large craters like Tycho and Copernicus, it's recommended that you record the times when the shadow touches the two opposite edges of the crater. The average of these times is equal to the instant of crater bisection.

    Here can be found predictions for the immersions and emersions of craters, mountains and a small mare on the Moon.


    Occultations (total and grazing) of many stars will occur during the total lunar eclipse of May 4 for observers throughout the Eastern Hemisphere and northeastern Brazil.

    David Dunham communicates:

    "Occultations of two 6th-mag. stars will be visible from most of Europe, with grazes of both near the Pyrenees Mountains. Eberhard Riedel has prepared a map that shows the paths of all grazing occultations of stars brighter than mag. 9.3 that will occur against the umbra during the partial or total phases of the eclipse. It can be found in an item at the top of my Web site at , or more directly, You can use Occult or LOW to calculate predictions of the total occultations for your location, or of graze paths for individual events, or Eberhard Riedel at can supply predictions of the graze paths.

    The southern-limit graze paths for both ZC 2111 (mag. 6.9) and ZC 2119 (mag. 6.5) cross the southernmost part of France, near Pic du Midi Observatory, and the paths seem to intersect just north of Andorra; it would be interesting to travel to the intersection place to observe both grazes without having to move. In northeastern Spain, Carles Schnabel of the Agupacio Astronomica de Sabadell, (e-mail, writes:

    "We are preparing an expedition to observe the grazing occultation of ZC 2119 on the [Mediterranean] coast, between Girona and Barcelona, exactly between Malgrat and Calella. This event occurs during the totality of the lunar eclipse, so it may be an extraordinary phenomenon. You are invited to join our expedition."

    Most remarkable will be the occultation during totality of the 2.8-mag. star alpha 2 Librae = ZC 2118 = Zubenelgenubi for observers in southern Africa, as noted on pages 104 and 106 of my article in this January issue of Sky and Telescope (with northern limit shown on the map on p. 103). Alfons Gabel is leading an expedition to the deserts of Namibia to observe this rare event, and there will be efforts to observe it in South Africa, as well - for details of this event, maps, and plans, see

    I hope that someone can record this year's event with one of the sensitive video cameras that are available now (and much cheaper than the Ultricon I used in 1985; see below), possibly one in color, to show the eclipsed part of the Moon much better.

    I think Alfons Gabel has already left to travel to Namibia, so I don't know if he will be able to receive e-mail or not at Observers in South Africa can get information about efforts to observe the graze there from Brian Fraser at

    The last time a star this bright was occulted during a total lunar eclipse was on May 4, 1985, a 19-year Meton cycle earlier, when the same star was occulted across most of Africa. In that case, the southern limit passed over South Africa, where dozens of observers organized by the late Danie Overbeek observed the graze, some without optical aid. The northern limit passed from Algeria to Somalia; at that time, the only country crossed by that path with friendly relations with the U.S.A. was Sudan, so Paul Maley, a few other observers from Houston, TX, and I made arrangements to go there to observe the event; we had valuable help from the physics department of Khartoum University and use of a transit satellite navigation receiver from a local oil company. I managed to video record the occultation with a cluncky Ultricon camera attached to a C5; you can see parts of that recording that are in large .avi files that my wife, Joan, digitized from a time-inserted copy of the orginal tape. They can be downloaded from my Web site at but you need a fast connection.

    Several years ago, Jean Meeus wrote an article about lunar eclipse occultations, examining all possibilities up to 2050. He and G. P. Konnen published it as "Occultations of Bright Stars by the Eclipsed Moon" in Journal of the British Astronomical Association, Vol. 85, No. 1, pp. 17-24 (1974). After May 4th this year, there will not be another chance to observe an occultation of a 3rd-mag. or brighter star until May 6, 2050 (I incorrectly said 2049 on the Web site; I'll correct that Monday), when Zubenelgenubi will again be occulted by the totally eclipsed Moon. Unfortunately, that event will be visible only from Antarctica, and at low altitude from the Falkland Islands and Tierra del Fuego; the northern limit passes entirely south of South Africa. Konnen and Meeus' article also mentions an occultation of Zubenelgenubi by the totally eclipsed Moon a Meton cycle later, on 2069 May 6, but I could not find that event with Occult. Occult predicted many occultations during that eclipse for a location in eastern Antarctica, including a nearly central occultation of 8th-mag. ZC 2122, but Zubenelgenubi is about 40' south of that star, so maybe the 2069 event is a mistake? The next Zubenelgenubi event after that with a totally eclipsed Moon is on 2134 May 8."

    Next lunar eclipse

    This year will see another total lunar eclipse on October 28. This eclipse will be visible from Europe and Africa as well as the Americas.

    Venus transit

    Tuesday 8 June 2004 will witness an extremely rare Venus transit. The planet Venus will cross the Sun disk's and will be seen in silhouet as a lage black spot. The latest Venus transit occcured in 1882, 122 years ago. So no human alive on Earth has ever witnessed a Venus transit!

    June 8, 2004: Venus transit

    Astronet in cooperation with Kennislink, Copernicus Public Observatory, Museum Observatory Sonnenborgh, the Dutch research school for astronomy in the Netherlands (NOVA), the European Southern Observatory (ESO), de Dutch Open Telescope (DOT) on la Palma (Canary Islands), Utrecht University Museum and several other parties will organize a live webcast of the Venus transit and act as a node for on line calculation of the Sun-Earth distance through the website This website will be activated early May and will contain all necessary information of how to observe the Venus transit safely and how to calculate the distance between the Sun and Earth by combining observations from all continents that can witness this transit.

    Carl Koppeschaar


    May 4, 2004 total lunar eclipse:

  • Sky & Telescope: The Moon goes dark
  • National Geogrpahic News: Sky-Watchers Await Total Lunar Eclipse on Thursday
  • Lunar Eclipse May 4 For Asia, Australia and Europe
  • Total Lunar Eclipse: May 4, 2004
  • Royal Astronomical Society: Lunar eclipse on 4th May
  • Hong Kong Observatory: Total Lunar eclipse on 5 May 2004
  • Australian Astronomy: Total Lunar Eclipse 5 May 2004

  • General information:

  • Crater Timings During Lunar Eclipses
  • Danjon Scale of Lunar Eclipse Brightness
  • Lunar Eclipse Photography

    Previous webcasts organized by Astronet:

  • Totale maansverduistering 8/9 november 2003
  • Annular solar eclipse, May 31, 2003
  • Total lunar eclipse, May 15-16, 2003
  • Mercury transit, May 7, 2003