Equinox

In the Lamppost station there is a photograph of the island from 1954.  Specifically, Sept. 23rd, 1954.  This was the date of the late-year equinox that year.  In 2004, the same equinox landed on Sept. 22... the date flight 815 crashed on the island.  Some sources have Naomi finding the island on the late-year solstice of 2004.  Is all of this coincidence? I doubt it.

Now, Henry Gale is claimed by Ben (when he was pretending to BE Henry) to have arrived... well, not on an equinox or a solstice.  And we don't know about when Desmond arrived.  But these dates we do know are either Easter eggs or they hold some significance.

Claire claimed to know a few things about astrology.  If she knew enough, she ought to be able to recognize certain constellations in the night sky and have some familiarity regarding where they should be relative to time of year and location of the observer.  If the island jumps around in space and time, a star-gazer would notice.  She would also have a sense of when the equinoxes and solstices are, as they typically mark the edges of zodiac signs.  When Claire first mentioned knowing something about astrology, that seemed important, but it hasn't come up again since (waaaay back in season 1).  Might it yet serve as an important clue?