I’ve been poking around with

I’ve been poking around with Birth Sky stuff again. The basic idea is finding planetary ephemeris data on the web and then plotting it automatically, maybe every day. I’m using MATLAB to generate the chart: here’s an early example. I’ve found several good ephemeris sites.

  • Your sky is good. They’re in Switzerland and have a secondary server in the .to domain, but it seems pretty flaky.
  • Web MICA, run by the US Naval Observatory, is also good, but doesn’t permit URL hacking to call the program. It’s all form driven, which doesn’t do me any good from an automation point of view.
  • Heavens Above, hosted in Germany, is one of the nicest and most complete stargazing sites.

Unfortunately, none of these sites seems to give me a way to use a single URL to return planet positions at an arbitrary time. More about this later.
By the way, “Your sky” has a particularly nice “illuminated Earth” clock page that is definitely worth a visit.