The Astronomy Focus Group will suggest scientific research from the transit of Venus for interested observers. Contact the Astronomy Focus Group Chair Sara Seager.

On June 8, 2004 Venus will transit the sun for the first time in over a hundred years. There are three categories of scientifically useful observations. For more details, see the Venus Transit Observations FAQ.

The first category of observations is of "Venus as an extrasolar planet". Observational data at specfic wavelengths (both photometry and spectroscopy) will enable extrasolar planet atmosphere modelers to thoroughly test their transmission spectra models. Useful observations include: 1) spectral features: low resolution, near-IR spectra; 2) photometric imaging at any wavelength during ingress and egress to measure the refraction effect.

The second category of observations is related to testing the feasibility of understanding transiting planet atmospheres. These observations would be of the spatially integrated solar disk (for example by observing moonshine, or observing with a tiny telescope.) Obtaining data to help understand how the spectral lines of the sun change as Venus transits will be immensely helpful.

The third category of observations is to learn something new about Venus itself. One example is very high spectral resolution (R > 200000) visible-wavelength spectra to detect previously unknown trace elemetns in the Venusian atmosphere. The solar photons will travel through long path lengths in the Venusian atmosphere thus being absorbed even by atomic or molecular species present only in tiny abundances.

Watch this site for predictions of line strengths. Also see the Venus Transit Observations FAQ.

The transit of Venus is barely visible from the US. Europe, Asia, and parts of Africa and Russia will enjoy large parts of the 6 hour transit.

While solar observatories are already equipped to observe the sun, astronomical observatories fitted with masks to stop down the telescope aperture will also be useful. The latter with near-IR low resolution spectrographs, very high resolultion visible-wavelength optical spectrographs, or broad-band photometric capabilities will be able to contribute scientifically useful data. In addition, small, transportable telescopes with fast read out CCDs will also be useful.

Images from photographic plates of the Transit of Venus (Venus crossing the face of the Sun), a very rare phenomenon that last occurred in 1874 and 1882.
Courtesy, The Naval Observatory.