|MadSci Network: Astronomy|
The planets can easily be tracked during the day. Jupiter and Venus can be seen during the day also, but never through the clouds, no matter what kind of detector you build. Clouds are very good UV,VIS,IR absorbers. To find them visually obtain their Right Ascension coordinates for the specific date. Obtain the same for the sun, using: http://ssd.jpl.nasa.gov/cgi-bin/eph If their RA is > that of the sun they will be farther East in the sky. If their RA is < that of the sun they will be farther West in the sky. Any telescope can be set to the sun, and then moved in RA to the position of the planet. Once the telescope is pointed to the correct area of the sky, you can look for it without any visual aid. BUT try and find it without getting some pointing direction first is nearly impossible. [Moderator's note: the only way I can think of to "see" planets through clouds is with radio waves. But most planets don't emit very much in the radio (with the exception of Jupiter), and I don't think a backyard-type dish would be sensitive enough to detect them.]
Try the links in the MadSci Library for more information on Astronomy.