On June 5th, 2012 one of the rarest of planetary alignments will be observable in the Houston area. The planet Venus will be observed crossing the disk of the sun. This alignment comes in pairs that are eight years apart but the pairs are separated by over a century. The most recent transit of Venus was in June 2004 and a puzzle cache celebrated the event. Miss this one and only your offspring will see the next one in 2117.
We now know the distance from the earth to the sun and the size of the solar system but this was not so in the time of Johannes Kepler and Isaac Newton. Those physics giants determined the positions of the planets but it was based on the relative distance from the earth to the sun known as an astronomical unit, a distance that was not well known. At that time, Edmond Halley (of comet fame), proposed that by triangulation, observations of the transit of Venus would allow calculation of the distance from the earth to the sun.
The 2012 full transit of Venus across the face of the sun occurs over six hours. Some locations on earth will see the total transit, other locations will see none at all, and in places such as in the Houston vicinity, part of the transit will be seen. We will be able to see the beginning of the transit at 5:10 PM CDT but before the completion of the transit the sun will have set at 8:21 PM CDT. As with all observations of the sun, safe viewing is critical to prevent eye damage. Venus will be only a tiny speck to the naked eye. Binoculars or a telescope equipped with the proper solar filters will provide a better viewing experience. Oh, the puzzle! It is pretty simple. Go the listed coordinates and SAFELY enjoy the transit. As the sun dips below the horizon, travel 420 feet in the direction of the setting sun and there you will find the cache container wedged between two boulders. If there are complications such as weather obscuring the sun or you cannot be there on the date of the transit or if you want to be FTF, simply determine the bearing of the setting sun, make a projection and the cache will be yours.
You can validate your puzzle solution with certitude.