Suncalc is a nifty online app that lets you input a geolocation and a date, and then uses google maps to graphically display the azimuth for the sunrise, sunset, and current time, for that particular date. Example: the sunset for the May 28 Manhattanhenge.
Ancient observatories from space Satellite images of Angkor Wat, Chichen Itza, Chaco Canyon, Stonehenge, Teotihuacan, and others. The observers, observed. High res images available.
The National Maritime Museum, Greenwich has some excellent online collections related to maritime history and technology, including telescopes, marine chronometers, sundials, and a whole lot more. Some stuff I've been looking at: John Harrison's chronometers (described in Dava Sobel's book Longitude), polyhedral sundials, and pocket globes.
Chasing Venus Transits of Venus occur every 130 years or so when Venus can be observed passing across the face of the sun. Chasing Venus is an online exhibition by Smithsonian Institution Libraries that tells the story of how the transit has been observed since the 17th century, with early observations in England, illustrated accounts of expeditions by 18th century astronomers to various parts of the world, and early uses of photography to record observations in the 19th century. Includes links to animations of transits reconstructed from Victorian photographs, and details of a lecture series on Thursdays in April and May (first one April 8). The first transit since 1882 is this year.
Astronomy in Japan by Steve Renshaw and Saori Ihara, describes the cultural history of astronomy in Japan, including lunar and solar New Year festivals, the star lore of Orion and other constellations, star festivals, shrines to meteorites, 17th century observations of a comet, celestial alignments in the urban fabric of early Kyoto, and much else besides.
Mercury, Venus, Mars, Jupiter and Saturn, the five planets visible to the naked eye, can all be seen simultaneously after sunset over the next few weeks. Viewing details. The next opportunity will be in 2036.
The transit of Mercury. About thirteen times a century, the orbits of Earth and Mercury align in such a way that Mercury can be observed passing across the disk of the sun. The next transit is from 0740 to 1317 GMT, May 7th, and will be webcast from NASA's orbiting Solar and Heliospheric Observatory Hot Shots page. NASA also has a piece on the seventeenth century mathematician and astronomerJohannes Kepler, who predicted (but died before observing) transits of Mercury and Venus.More info on space. com, including a viewer's guide and a history of previous observations.