Mercury Transit Nov 11

Mercury Crosses the Sun Nov 11, 2019
by John Hlynialuk

NOTE: this entire event requires proper solar filters for viewing. Serious eye damage or blindness may result from looking at the Sun without proper filters protecting your eyes, telescopes and/or cameras.

A once-in-a-lifetime transit of the Sun by Mercury occurs on the morning of Mon, Nov 11, Remembrance Day. The tiny disk of Mercury starts its pass across the Sun at 7:36 am EST locally and continues for 5 hours 28 minutes until 1:04 pm EST when it finally leaves the Sun’s face.

You cannot see Mercury without optical aid since it has such a small silhouette. A telescope at medium power with solar filter over the objective lens or mirror is required. Follow all precautions for proper solar viewing.
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Image Right: Mercury Transit of Nov 8, 2006 by John H.
Mercury is the small dot below and right of the large sunspot at 9 o’cloc

Mercury is tiny (only 10 arc-seconds across) compared to Venus which last transited the Sun in 2004 and 2012. Venus was 6 times larger than Mercury, but transits of Venus are very rare. The next two Venus transit occur in 2117 and in 2125, then another century or so elapses before another pair.

Mercury passes across the Sun much more often. We saw transits in 2003, 2006 and 2016 in this century, and 9 more are due before 2100. BAS members observed both the 2006 and 2016 transits. However, make sure to the attempt this November sighting because, the next Mercury transit does not happen until 2032 and that one will be over before sunrise in North America! Neither will the one that follows next in 2039 be visible from most of the western hemisphere. North Americans have to wait almost 30 years until May 7, 2049 to see a Mercury transit locally.

BAS members will set up telescopes (properly-filtered) at the Fox Observatory 7:00 am weather-permitting) on Nov 11 for viewing. There is a 5-½ hour window of opportunity and even if there are some clouds, we hope to have some clear sky over that interval. By an interesting astronomical coincidence, this is Remembrance Day which however, is NOT a statutory holiday in Ontario, Quebec and two other provinces.

Canon 60D at prime focus of the 10-inch Bishop scope at 2500 mm focal length, f/10,
1/1000 s. at 200 ISO. Photo May 9, 2016 by JH from Fox Observatory.

We will feature live views through our various telescopes during the transit. Once again note that all will be equipped with safe solar filters. Solar filter material can be obtained from various sources online but note that you will see nothing with solar eclipse glasses if you have a pair left over from 2017. Mercury is too small to be seen with the naked eye even as a silhouette against the sun’s surface.