Yesterday evening, driving home from a send-off party for a friend moving to Brazil, we passed a brush fire. Hearing traffic was delayed by a brush fire was odd, since April isn't exactly the season for it, nor is the marshy land just west of Manhattan the territory, but as we exited the Lincoln Tunnel, there it was: a smoke-belching orange display, vibrant in the gathering dusk, a few dozen meters from the inbound lanes. Seeing it took me back to the great brush fire of '85 in Ojai, California.
I was there for six weeks as part of a summer science camp. Thirty-six students, divided into groups of three, were to track the paths of five asteroids and a comet. The perennial brush fires of the great west chose that year to strike Ojai, driving us from the school grounds for two or three days. But three days' delay was nothing compared to the delays to our observations. See, you need at least three points to plot an elliptical orbit, but most of us only had one or two good photographic plates of our assigned celestial body by the time we evacuated. And, though the fire retreated and we returned to school, the sky was too thick with soot to get any more accurate measurements for two weeks afterwards.
Every team had made three attempts by then, but getting a good plate was a tricky matter. Large asteroids are dim enough that we needed to expose our photographic plates for fifteen minutes or so, and naturally, the sky moves in that time ? or rather, the earth rotates beneath the sky in that time. If you don't move the telescope precisely counter to the earth's rotation, your plate fills with streaks rather than precise pinpoints. And, since we didn't have the budget for automatic tracking, we had to do it by hand, fifteen excruciating minutes of peering through an eyepiece, toggling a pair of joysticks, trying to keep a barely-visible blip dead in the crosshairs. Small wonder only one team got three good plates in three tries.
Luckily, that team was mine. With that head start, we never had to compete for lab space or equipment time, and worked out the orbit of 29 Amphitrite at a nice, leisurely pace while everyone else worked around the clock in tight shifts, nights in the observatory, days at the measuring equipment and computers. Our ephemeris, the numbers measuring various aspects of the orbit, came out pretty well, too, or at least close to the accepted mean values drawn from decades of observations and collected in a world database on orbits. Something has always bothered me about our work, though.
Part of the point of the project was for we bright but undertrained high school students to add our data to that world database. I said our emphemeris were pretty good. Our semi-major axis, eccentricity, inclination, and true anomaly were good matches. Our right ascension, the angle between the orbit's longest axis and an arbitrary coordinate, was about 30° off. And our argument of perigree, the angle between the longest axis and the equatorial plane of the sun, was something like 120° off; we could have done better by picking a random number. Briefly, we measured the size and shape of the orbit well, but measured its orientation poorly. That data went into the same huge pool of values that NASA uses to plot rocket trajectories, and astronomers use to point their telescopes, and I know our figures were far more reliable than many other groups at science camp. My team got to sleep occasionally, after all. Tossing out suspect figures was unthinkable; it's bad science to ignore data that doesn't match your expectations. So somewhere in the vast pool of astronomical knowledge, my amateur figures are throwing somebody off by a minute quantity, inversely proportional to the number of people who have reported the orbit of 29 Amphitrite, and I can never take it back
I sincerely hope there aren't many amateur astronomers out there, mucking up the figures.