A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Francis Upchurch
Date: 2016 May 3, 07:16 -0700
Thanks Frank for the Mercury transit headsup.
I've often wondered why Halley, then Cook, Maskelyne et al could not have used the more common Mercury Transits to work out the solar parallax and therfore the earth/sun distance, the main objective of the Venus transit trips including Endeavour.
I always assumed it related to the Mercury/ sun distance being too small. Is that so, or are there any more fundamental reasons? If instruments were sensitive enough, would Mercury do it?
Either ways, if we get clear weather, I'm inviting the local school kids over for a Mercury transit party! Hope to work out the longitude of my garden at the same time from predicted GMT of start and finish. Has anyone else done this recently? I tried with Venus in 2012 and failed miserably. Don't think I'll be around for the next Venus transit, so Mercury it is!