May Brings an Astronomical Bonanza

April 29, 2003

Alan MacRobert, Senior Editor
  617-864-7360 x151,
Roger W. Sinnott, Senior Editor
  617-864-7360 x146,

Note to Editors/Producers: This release is accompanied by high-quality animations and illustrations; see details below.

Keep your eyes on the heavens throughout this coming month. Astronomically speaking, May is bustin' out all over! Those in the know — and in the right place at the right time — will be treated to a lunar eclipse, a solar eclipse, the passage of the planet Mercury in front of the Sun, and the nationwide celebration of Astronomy Day.

Transit of Mercury

The excitement begins on Wednesday, May 7th, when the Sun, the innermost planet Mercury, and the Earth will form a straight line in space. For five hours Mercury will crawl across the solar disk, appearing as a slowly moving black dot. Skywatchers throughout most of Europe, Africa, and Asia can see the entire event unfold. Those living in Japan, Alaska, parts of Australia, and the northeastern parts of North and South America will see part of the transit after sunrise or before sunset.

This is the first of 14 transits of Mercury to take place in the 21st century, and the first since November 1999. Mercury's next transit across the solar disk favors observers in Pacific Rim countries and will take place in 2006 on November 8th.

To watch the transit you must observe the Sun, which is very dangerous unless proper precautions are taken. Never look directly at the Sun, with or without optical aid, unless you have a safe solar filter and understand its instructions for use. Tips for observing the transit safely — either indirectly by projection or directly through properly filtered optics — appear below. We also provide tables listing the times to watch from various cities worldwide. If your city isn't listed, use the times given for the location nearest you.

Astronomy Day 2003

Saturday, May 10th, is Astronomy Day. This annual event, now celebrating its 30th anniversary, began as a high-profile way of drawing public attention to the science and the hobby through exhibits and activities at urban centers. It has since mushroomed in size and scope. Hundreds of astronomy clubs, observatories, museums, colleges, and planetariums worldwide now host family-oriented Astronomy Day events and festivities to show how enjoyable and exciting astronomy can be. For more information, see our online article "Astronomy Day: Bringing Astronomy to the People". To find a club or other astronomy-related organization near you, search's directory.

Since 1989 Sky & Telescope has given its prestigious Astronomy Day Award to the events or displays judged most successful in achieving the core concept of the event: "Bringing Astronomy to the People." The grand prizewinner receives a plaque awarded at the Astronomical League's annual convention and a $250 gift certificate from Sky Publishing, good toward the purchase of magazine subscriptions, books, star atlases, software, photographic prints, globes, or other products.

The Astronomical League maintains a Web page listing Astronomy Day events across the USA.

Lunar Eclipse

On Thursday night, May 15-16, the full Moon will pass directly through the northern part of the Earth's shadow, providing a colorful spectacle for skywatchers throughout the Americas, Europe, and Africa. For North Americans the 3¼-hour event happens in "prime time," from about 10 p.m. to 1:15 a.m. Eastern Daylight Time (7 p.m. to 10:15 p.m. Pacific Daylight Time, though the early partial phases occur before sunset/moonrise on the West Coast).

In early May Sky & Telescope will issue a more detailed press release about this eclipse, including a timetable and instructions on what to look for. Note that this is the first total lunar eclipse in 2½ years and the first one visible across the Americas since January 2000. This year brings two total eclipses of the Moon, and the second, on November 9th, will also be visible from the United States.

Solar Eclipse

At the end of the month, on Saturday morning, May 31st, the Moon will pass directly between the Earth and the Sun. The last time this happened, on December 4, 2002, skygazers in Africa and Australia witnessed a total solar eclipse. But this time the Moon will be a little farther from the Earth, and the Earth a little closer to the Sun, so the Moon's angular size won't be quite large enough to mask the Sun totally. Instead, skywatchers in Iceland, northern Scotland, and parts of Greenland will experience a brilliant ring of sunlight — the hallmark of an annular eclipse. Elsewhere across Europe, as well as for parts of Asia and North America, the Moon will glance across the Sun, taking no more than a "bite" out of its disk when viewed through a safe solar filter. See our accompanying timetable for details.

Solar Safety

When viewing the Sun, regardless of the time of day, simple, proper precautions are required. For the May 31st solar eclipse, it is easy to view the event indoors by pinhole projection. Use a pin to poke a tiny hole in an index card. Hold the card up to the Sun in a window, and display the image of the Sun projected by the pinhole onto a solid white background (for example, a sheet of paper). You'll be able to watch the Sun go through all phases of the eclipse. To see tiny Mercury move across the Sun on May 7th, you'll need a larger, sharper image, which you can get by projection through a small telescope or binoculars.

For those who prefer direct views, safe solar filters for telescopic or naked-eye observing are available from a variety of suppliers. Other safe ways to observe the Sun are described in a series of articles in the Observing section of

More information about all these events, and how to enjoy them, appears in the May 2003 issue of Sky & Telescope magazine.

Sky & Telescope is making the following illustrations available to the news media. Permission is granted for one-time, nonexclusive use in print and broadcast media, as long as appropriate credits (as noted in each caption) are included. Web publication must include a link to

Transit of Mercury
NASA's Transition Region and Coronal Explorer (TRACE) satellite witnessed Mercury's transit across the Sun's disk on November 17, 1999. For a movie of this event, download the animated GIF (2.5 megabytes) by FTP.
Courtesy NASA and the TRACE project.
Transit of Mercury Visibility
Almost anywhere in Europe, Asia, and Africa on May 7, 2003, observers with clear skies and safely filtered telescopes should be able to see tiny Mercury in silhouette against the Sun's disk. Only the beginning or end of the transit is visible from parts of the Americas and Australia. Click on the image to download a publication-quality JPEG (500 kilobytes) by FTP.
Sky & Telescope illustration by Steven Simpson.
Visitors to the Charles Hayden Planetarium at Boston’s Museum of Science were treated to views of the Sun through a filtered 6-inch refractor during the Astronomy Day celebration in April 2001. Click on the image to download a publication-quality JPEG (5.4 megabytes) by FTP.
Sky & Telescope photo by Edwin L. Aguirre.
Aligning his camera on the same star for nine successive exposures, S&T contributing photographer Akira Fujii captured this record of the Moon’s progress dead center through the Earth’s shadow in July 2000. On May 15–16, 2003, another total lunar eclipse will be visible from North America. Click on the image to download a publication-quality JPEG (1.5 megabytes) by FTP.
Photo by Akira Fujii, courtesy Sky & Telescope.
partial solar eclipse
The annular eclipse of May 10, 1994, was seen along a narrow path across Mexico and the United States. However, virtually all North Americans with clear skies saw the Sun's disk at least partially covered by the Moon. This image was taken with an 8-inch Schmidt-Cassegrain telescope from Ogonquit, Maine. Click on the image to download a publication-quality JPEG (500 kilobytes) by FTP.
Sky & Telescope photo by Rick Fienberg.
annular eclipse
The annular eclipse of May 10, 1994, was seen along a narrow path across Mexico and the United States. This image was taken with an 8-inch Schmidt-Cassegrain telescope from Ogunquit, Maine. Click on the image to download a publication-quality JPEG (100 kilobytes) by FTP.
Sky & Telescope photo by Rick Fienberg.
Viewing the Sun
It's not safe to observe the Sun with unprotected eyes, and sunglasses — no matter how dark — are not safe either. Two video clips (TRT: 13 seconds each) show the proper use of specially filtered 'eclipse' glasses and a #13 or #14 welder's glass. These can be viewed or downloaded as QuickTime movies, either as low resolution (2.2 megabytes) or broadcast-quality resolution (102 megabytes).
Sky & Telescope video.

Beginning of Transit of Mercury in Afternoon, May 6-7, 2003
Place Contact I Contact II Sunset
Perth, Australia 1:14 p.m. 1:19 p.m. 5:34 p.m.
Darwin, Australia 2:43 p.m. 2:48 p.m. 6:33 p.m.
Sydney, Australia 3:14 p.m. 3:18 p.m. 5:09 p.m.
Sapporo, Japan 2:11 p.m. 2:15 p.m. 6:42 p.m.
Tokyo, Japan 2:11 p.m. 2:16 p.m. 6:32 p.m.
Kagoshima, Japan 2:11 p.m. 2:16 p.m. 7:01 p.m.
Naha, Okinawa 2:12 p.m. 2:16 p.m. 7:04 p.m.
Anchorage, AK 9:10 p.m. 9:14 p.m. 10:18 p.m.
Civil times are used in this table. Note: The transit takes place on May 7th at most locations, but on the afternoon of May 6th in Alaska (just east of the International Date Line). Contacts I and II are the times when Mercury begins to dent the Sun's edge and when it appears fully silhouetted against the Sun, respectively.
End of Transit of Mercury in Morning, May 7, 2003
Place Sunrise Contact III Contact IV
Halifax, NS 4:57 a.m. 6:29 a.m. 6:34 a.m.
Montreal, PQ 5:34 a.m. 6:29 a.m. 6:34 a.m.
Toronto, ON 6:02 a.m. 6:29 a.m. 6:34 a.m.
Boston, MA 5:32 a.m. 6:29 a.m. 6:34 a.m.
Pittsburgh, PA 6:12 a.m. 6:29 a.m. 6:34 a.m.
Washington, DC 6:04 a.m. 6:29 a.m. 6:34 a.m.
San Juan, PR 5:54 a.m. 6:29 a.m. 6:34 a.m.
Fortaleza, Brazil 5:32 a.m. 7:29 a.m. 7:33 a.m.
When the Sun rises at each of these places, Mercury will already be visible as a black speck on the solar disk. Civil times are given here. Contacts III and IV are the times when Mercury last appears fully silhouetted against the Sun and when it last dents the Sun's edge, respectively.
Transit of Mercury, May 7, 2003
Place Contact I Contact II Contact III Contact IV
Reykjavik, Iceland 5:10 a.m. 5:15 a.m. 10:28 a.m. 10:33 a.m.
London, England 6:11 a.m. 6:15 a.m. 11:28 a.m. 11:32 a.m.
Stockholm, Sweden 7:11 a.m. 7:15 a.m. 12:28 p.m. 12:32 p.m.
Berlin, Germany 7:11 a.m. 7:15 a.m. 12:28 p.m. 12:32 p.m.
Paris, France 7:11 a.m. 7:15 a.m. 12:28 p.m. 12:32 p.m.
Madrid, Spain 7:11 a.m. 7:16 a.m. 11:28 a.m. 11:32 a.m.
Rome, Italy 7:11 a.m. 7:16 a.m. 12:28 p.m. 12:32 p.m.
Johannesburg, S.A. 7:14 a.m. 7:19 a.m. 12:26 p.m. 12:30 p.m.
Istanbul, Turkey 8:12 a.m. 8:16 a.m. 1:27 p.m. 1:31 p.m.
Cairo, Egypt 8:12 a.m. 8:16 a.m. 1:27 p.m. 1:31 p.m.
Moscow, Russia 9:11 a.m. 9:15 a.m. 2:27 p.m. 2:31 p.m.
Tehran, Iran 9:42 a.m. 9:46 a.m. 2:56 p.m. 3:01 p.m.
Bombay, India 10:43 a.m. 10:47 a.m. 3:55 p.m. 4:00 p.m.
Bangkok, Thailand 12:13 p.m. 12:17 p.m. 5:25 p.m. 5:29 p.m.
Beijing, China 1:11 p.m. 1:16 p.m. 6:26 p.m. 6:30 p.m.
Taipei, Taiwan 1:12 p.m. 1:16 p.m. 6:25 p.m. -
Hong Kong, China 1:12 p.m. 1:17 p.m. 6:25 p.m. 6:29 p.m.
Seoul, S. Korea 2:11 p.m. 2:16 p.m. 7:26 p.m. -
Civil times are given throughout, including daylight-saving ("summer") time where in use. Note that the values for Bombay and Tehran are 5h 30m and 4h 30m, respectively, greater than Universal Time.

Eclipse of the Sun, May 31, 2003
Location First Contact Max. Eclipse Obscur. Last Contact
Reykjavik, Iceland 4:04 a.m. (annular) 5:01 a.m.
Dublin, Ireland 5:37 a.m.
Edinburgh, Scotland 4:43 a.m. 0.88 5:40 a.m.
London, England 5:32 a.m.
Rome, Italy 6:10 a.m.
Bern, Switzerland 6:20 a.m.
Paris, France 6:26 a.m.
Brussels, Belgium 6:28 a.m.
Amsterdam, Neth. 5:33 a.m. 0.84 6:30 a.m.
Vienna, Austria 5:20 a.m. 0.76 6:19 a.m.
Warsaw, Poland 4:27 a.m. 5:24 a.m. 0.77 6:24 a.m.
Prague, Czech Rep. 5:24 a.m. 0.79 6:23 a.m.
Berlin, Germany 5:28 a.m. 0.81 6:27 a.m.
Stockholm, Sweden 4:38 a.m. 5:36 a.m. 0.83 6:38 a.m.
Cairo, Egypt 6:38 a.m.
Athens, Greece 6:57 a.m.
Jerusalem, Israel 5:46 a.m. 0.42 6:40 a.m.
Istanbul, Turkey 6:03 a.m. 0.61 7:01 a.m.
Helsinki, Finland 5:37 a.m. 6:37 a.m. 0.80 7:40 a.m.
Baghdad, Iraq 6:44 a.m. 0.37 7:39 a.m.
Moscow, Russia 6:24 a.m. 7:25 a.m. 0.70 8:30 a.m.
St. Petersburg, Rus. 6:34 a.m. 7:34 a.m. 0.77 8:39 a.m.
Tehran, Iran 6:23 a.m. 7:16 a.m. 0.35 8:13 a.m.
Kabul, Afghanistan 6:26 a.m. 7:13 a.m. 0.15 8:04 a.m.
New Delhi, India 7:36 a.m. 8:04 a.m. 0.02 8:32 a.m.
Islamabad, Pakistan 7:59 a.m. 8:42 a.m. 0.10 9:29 a.m.
Anchorage, AK 8:31 p.m. 9:28 p.m. 0.42 10:21 p.m.
Civil times of the eclipse are given throughout. The eclipse occurs on May 31st everywhere except Anchorage, Alaska, where it is an afternoon event on May 30th. Obscur. means obscuration, the fraction of the Sun's area covered at maximum eclipse.
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