"Mike Dworetsky" wrote:

My take on this is that the 4 hour discrepancy means that the locations on
Earth that see the next transit in the series, but at the same node, will be
at different longitudes. A bit like solar eclipse saros.

More significant is that Venus will take a slightly different (but
parallel path across the Sun, until, after 1000 plus years it will
miss altogether: this particular Saros will come to an end.

Judging by Starry Night the June tracks are going to move up (towards
and beyond the centre of the Sun's disc) as the centuries go by, and
the December tracks move down.

In fact Starry night gives Venus close to but missing the Sun
altogether in December 2854 - as does SkyMap Pro. I shall have to
scratch that one out of my diary. Damn - I'd cancelled my skiing
holiday for it..

Presumably there will be some grazing transits at some point, transits
visible from say indide the Arctic Circle, but not elsewhere - which
would kill the parallax possibilities stone dead.

Kepler, Horrocks and Halley were fortunate in hitting just the right
part of the transit Saros.

--
Martin Frey
http://www.hadastro.org.uk
N 51 02 E 0 47