Tom Wyant

The Astro-satpass distribution contains classes to compute satellite position and visibility. The recent ‘Heads up’ posts were the latest chapter in its life, and that chapter comes to an end with the release of version 0.040. The only code modification since the most-recent ‘Heads up’ was to have the satpass script take advantage of the new lazy_pass_position attribute.

So who uses this distribution anyway? Since it is open source, the only users I find out about are the ones who write me — usually with a problem of some sort. Most of these represent an opportunity to improve the distribution, even if only to try to make the documentation a little clearer.

My impression from the correspondence is that most uses of this package are casual — hobbyists, interested amateurs, and the like. This is not to deprecate those users: I am one myself.

But it appears to be be in serious, day-to-day use in at least four places. These are:

• An European Space Agency subcontractor uses it to help his communications antennae acquire and track satellites, and to plan communications. No, this is not a real-time use of Perl; the antennae can track a satellite once it is acquired, but they need to be told where to start, and they need help to prevent their being hijacked by stronger signals.

• A web service that provides notification of International Space Station overflights is in the throes of adopting this package to do its predictions.

• A radio astronomer uses this package to monitor the positions of certain satellites so that he can plan his observing.

• A meteorologist who needs to avoid satellite interference with his Doppler radar uses this package to know when the relevant satellites are above the horizon.

Now, I have not quizzed any of these people over and above whatever their problem at hand was. But my impression is that only the first two are professional programmers. The last two are people in technical jobs of which programming is only a part.

I mention this last because there have been some posts recently about the market and mind share of Perl among professional programmers. But to what extent should our marketing take into account other sorts of users? I do not know the answer, but thought it might be useful to ask the question.