Saturday, March 30, 2019


Mark your calendar: On Monday, Nov 11th, Mercury will pass directly in front the Sun. The rare transit begins at 12:35 UT (7:35 am EST) and lasts for almost six hours. Mercury's tiny disk—jet black and perfectly round—will glide slowly across the face of the sun, as shown in this movie created by science-artist Larry Koehn of

People in every continent except Australia can see at least a portion of the crossing. In the USA, the best place to be is on the Atlantic coast, where the entire transit is visible. On the Pacific coast the transit will already be in progress at sunrise.
Warning! Mercury covers only a tiny fraction of the sun's surface, so staring at the sun remains just as painful and dangerous as ever. But with a proper filter, the Transit of Mercury can be a marvelous experience.

There are many ways to safely observe the sun, e.g., using eclipse glasses or via projection. Nothing beats a telescope equipped with an H-alpha filter. H-alpha filters are narrowly tuned to the red glow of solar hydrogen. They reveal the sun as a boiling inferno, cross-crossed by dark magnetic filaments. The sight of Mercury navigating this starscape could be mind blowing.

Transits of Mercury occur only 13 times each century. The next one won't occur until Nov. 13, 2032. This is an unusual event, not to be missed, so stay tuned.

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