Shooting with the BBC
Apparently the BBC has a TV program called "What the Past Did for Us", which is sort of a popular presentation of some historical developments in science and technology. I've never seen it, but it sounds interesting! Anyway, they are planning an episode for September or October on the subject of science in India, and a crew came to Jaipur a couple of days ago to film some footage at the Jantar Mantar, the pre-telescopic observatory built in the early 18th century by Jaipur's founder, Maharaja Jai Singh. So I ended up being a sort of technical consultant about the math and astronomy aspects, and did the shoot with them. I visit the Jantar Mantar quite frequently anyway, being convinced that it's the most fun you can have in India for 10 rupees (or anywhere in the world, probably, since 10 rupees isn't much), so it was no burden. (You can see some photographs of the observatory online at http://home.planet.nl/~e.noordanus/india/tekst_uk/jaipur_3_uk.htm. I like conscientious travellers who take lots of pictures and put them up on the web so I don't have to.)
Lots of fun, although the rule of thumb about needing to shoot an hour for every minute of footage in the final film seems to be true: they are planning to make this sequence about 3--5 minutes long, and we were there from before noon till after 4:00. It was nice to be able to get into some of the places that are usually off-limits, such as the Sasthamsa Yantra: a dark chamber with pinholes in the ceiling allowing an image of the sun to fall onto a scale oriented north-south, so you can measure the solar declination at noon (and incidentally get a quite precise measurement of when it *is* noon). The resident bats and pigeons were a little restless at being disturbed, and I would have thought it was a bit too dark to make for good TV, but we were able to time it so that we hit the true local noon observation (twenty minutes or so after noon IST). It was pretty neat to see the image of the sun steadily traveling down the wall and moving across the scale and then across the floor. We don't notice how quickly the sun really appears to move across the sky! (except while watching a sunset, perhaps).
You history of math buffs hoping for a lot of detail about how the instruments work won't get much of it from the show, I'm afraid. The attitude was lighthearted rather than earnestly technical, with some descriptions no more detailed than "Samrat Yantra. BIG sundial!" and so forth. (I did get a chance to explain an equatorial sundial as basically a skeleton model of the earth and the passage of time during the day as representing the turning of the equator, though, so we'll see if that makes it into the final cut.) But it captured a pretty good general impression of what the Jantar Mantar's about and what it looks like, as far as I could tell.
Not the place to spend an April afternoon in Jaipur if you can avoid it, though. You may have heard the old malapropism that "the climate of Bombay is such that the inhabitants have to live elsewhere", and the climate of Jaipur is too, at least after the spring equinox. Max temp that day was 40.6 degrees C (come May, we'll wish it were still that cool!), and of course an observatory by its nature has to be laid out on open ground with no visual obstructions, meaning no shade. I stayed in the shadow of the instruments or under my trusty folding umbrella as much as possible, but we were all pretty burnt and tired when the shooting was over. The crew then took off to film the remaining sites on their agenda (they're shooting a water-clock near Kota, I believe, and a temple in Khajuraho where they're going to get a pandit or Brahmana priest to recite some of the ancient Yajurveda hymns to the numbers: "praise to ten, praise to a hundred, praise to a thousand" and so forth). Sounds like fun, as well as a lot of work, and it will be interesting to see what they make of it in the eventual episode.
—— Kim Plofker
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