Occurring in pairs
separated by over a hundred years,
there have now been only eight transits of Venus
since the invention of the telescope in 1608.
The next will be in December of 2117.
But many modern telescopes and cameras were trained on
Venus transit, capturing the planet
in rare silhouette
against the Sun.
In this sharp telescopic view from Georgia, USA, a narrowband
H-alpha filter was used to show
the round planetary disk against a mottled solar surface with
dark filaments, sunspots, and prominences.
The transit itself lasted for 6 hours and 40 minutes.
Historically, astronomers used timings of the transit from
different locations to triangulate the distance to Venus,
while modern astronomers actively search for planets that
transit distant suns.