The GOES satellite captured the 2004 transit of Venus in X-ray wavelengths.

http://sxidata.ngdc.noaa.gov/archive/browse/special/SXI_SPECIAL_20040608_VENUS_09H.MPG
In images by the GOES satellites Solar X-Ray Imager (SXI), Venus appears as a dark disk about 1/30th the Sun’s apparent diameter. Since the Sun’s corona extends well above the disk, Venus was visible in silhouette for approximately 9 hours, versus the 6 hours seen from Earth. The path across the disk is from the southeast to the southwest. Movie (1.9 MB MPEG-1, 7 sec.) was created by NOAA's Space Weather Prediction Center.