Transit of Mercury 1999

Viewed with a special solar telescope which filters out all but a narrow band of red light,
the planet Mercury took approximately one hour to pass across the face of our Sun on November 15, 1999.
The last time a Transit of Mercury was visible was 1993 and the next time won't be until 2003.

Slideshow of Local Observers -

Image Collection in White light and Hydrogen Alpha

As common as it might seem, Mercury only passes directly between the Earth and Sun about 13 times a century. This alignment is called the Transit of Mercury. A big event for astronomer for ages, this unique view allows scientists a much clearer view of Mercury for measurements. Long ago, it was deduced that if two people placed at far distances on the earth were to observe and record exact times that Mercury intersected the sun, that the size and distance of Mercury could be calculated with very simple math. However, travel for such events was not as simple as today. To book passage to distant lands was not as simple as booking an airline flight today and proved a significant obstacle. However, the 1999 transit was viewable from nearly every corner of the globe.

A special treat was in store for parts of Australia. The path where Mercury would intersect the Sun was so close to the outer limb of the Sun that it would be catagorized as a grazing. This would mean that Mercury would be observed moving so snugly against the edge of the sun as to perhaps move in and out of view over imperfections in the Sun's limb.

Observers were easily able to compare the size of Mercury to the sunspot sizes with such a dynamic grouping of naked eye sunspot clusters. Just one day earlier, this same group of sunspots was believed to be responsible for the release of an M class flare. Could we be lucky enough to experience an aurora during the Leonids due to this? It's doubtfull, but still exciting.

Meanwhile, nationwide observers watched the weather patterns and waited in anxious anticipation, only to find the jet stream so far to the north that no clouds were seen anywhere in the midwest for days. Daily temperatures reached record highs across the country and passed the 80 degree mark in mid-November. At our location in the Greater Kansas City area, the transit of Mercury began at 3:13 pm and ended at 4:06 pm CST.

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All images, graphics, photos and text © 1999 Vic & Jennifer Winter, ICSTARS Astronomy