Title:

The Transit of Venus from the ground and from TRACE


Jay Pasachoff
Williams College



Abstract:

After an interval of 122 years, a transit of Venus across the
face of the sun occurred on June 8.  Once the "noble problem" of
astronomy in the 18th and 19th centuries, the basic way of
finding the scale of the universe (now rather done from Hubble
and WMAP), we decomposed the infamous black-drop effect, which
foiled accurate measurements for hundreds of years, using TRACE
(NASA's Transition Region and Coronal Explorer) observations of
a transit of Mercury, revealing the role of solar limb darkening
in addition to that expected from the telescope's point-spread
function. We have now extended the work with TRACE and
ground-based observations of the recent transit of Venus. We
discuss also potential ramifications of the transit observations
for future observations of exoplanet atmospheres during their
transits.