The May 7, 2003 transit of Mercury

After a number of rainy days, the sky finally started to clear out over CBA Belgium Observatory in the night of May 6 / 7, 2003. This was an excellent timing, giving me the opportunity to observe two entirely different celestial highlights. First of all, it allowed me to participate in an international observing campaign to study the rarely outbursting cataclysmic variable OU Vir. Second, on the morning of May 7th, the Sun's disk would show the tiny silhouette of Mercury, on its way for a 5 hours transit of the Sun.

All images were made with an Olympus C3030 Zoom digital camera, attached to a 0.35-m f/6.3 telescope (effectively reduced to 0.08-m). The image at left was obtained on May 7.372 UT, the one at right - showing Mercury close to a prominent sun spot - on May 7.374 UT.
(c) Tonny Vanmunster & Jean-Marie Biets

I had invited my long-time friend Jean-Marie Biets (an avid Belgian meteor enthusiast) to join me for the observation of the Mercury transit. We started our observing session around 7h UT, under good skies. At that moment, the transit was already well under way, and Mercury was easily visible as a dark "hole" in the Sun's disk. We used the 35-cm f/6.3 telescope at CBA Belgium Observatory, but reduced the aperture to 8-cm. A safe solar filter (Baader Astrosolar) was used to protect our eyes from the Sun's blinding intensity.

Jean-Marie Biets next to the telescope that was used to follow the transit Image obtained on May 7.436 UT, towards the end of the transit.

We attempted to make digital photographs of the event, using an Olympus C-3030 Zoom 3.1 megapixel camera, that was controlled via software using Sergei Menchenin's Cam2Com package (freeware). Since this was our very first attempt to photograph the Sun with a digital camera, it took us quite some time to find the right combination of focus / zoom / aperture and other settings. Below is a sample of the pictures we obtained, giving an impression of the progress of the transit. We continued to observe the event till about 10h32m UT, when the planet finally left the Sun.

"Hole in the sun rim" on May 7.437 UT

Last sight on May 7.438 UT


Towards the end of the transit, my two sons joined for a sight of the event (picture lower row left). Michiel observed the transit with a lot of interest (upper row), but it seems my youngest boy Niels (lower row right) will have to wait for the next transit, for a more comfortable observing position ;-)





Copyright © 2003 - Tonny Vanmunster.