Greenwich Royal Observatory

We've had two field trips so far for my class: the trip to Cambridge on Thursday, and a visit to the Royal Observatory in Greenwich the week before. The observatory was very interesting--I got to stand straddling the Prime Meridian--but old telescopes aren't very photogenic. So, unlike the visit to Cambridge, there are a manageable number of photos to share.

This is one of the mural quadrants installed during Edmund Halley's time as Royal Astronomer. This is a kind of telescope mounted on a quarter circle frame on a wall aligned north-south. This allowed the astronomer to measure the angular height of the star being observed.

Jantar Mantar in black and white

The curves and shadows make lovely abstracts.

The curve of time

These wings tell the time, among other things, more accurately than the crappy Timex watch I was wearing.

Among the sundials

These guys were taking pictures of each other goofing around one of the sundials. When they saw me taking pictures they posed for me.

Jantar Mantar

Seen from a distance it looks like a modern sculpture garden.

More Nadivalaya yantra

The two dials: one in sun, one in shade.

Astronomy Tuesday

Here's something a little different: one of the nineteen instruments at Jantar Mantar, the observatory at Jaipur built by the formidable Jai Singh II. (Jantar Mantar means roughly “calculating instrument.” The one in Jaipur is one of several that Jai Singh built.)

This sundial is part of a Nadivalaya yantra, a hemispherical sundial. There are two large dials mounted on opposite sides of a small building. They're both parallel to the plane of the Earth's equator so they tilt; one forward and one backwards. Depending on the season, the sun is either north or south of the equator, and so one dial is always in the sun and one is always in shadow, except at the equinox, when the sun strikes directly from the side.