Astronomers of different eras

We note that different kinds of people have become astronomers, depending on when they worked.

A couple of weeks ago we noted the increased specialization of astronomers over the years.  This wasn’t a new idea by any means; specialization is a feature of all intellectual activity over time, at least over any time that is conscious of the past.  Various history books will hold up various people as “the last one to know everything that was known in his time,” all of them centuries ago.  Today we remark on something less obvious: that the type of person who becomes an astronomer has changed over time, as the task and tools of astronomy have changed.

In the nineteenth century and before, an astronomer would measure the positions of stars and planets using clocks and cross-wires.  He (there were a few shes!) required good eyesight, careful calibration and procedures, and the ability to carry out laborious trigonometric calculations without error.  It was an all-night job (which could be very long, in England in winter) lasting into the day.  The tools and the output were tables of numbers.  The job description would feature “meticulous” prominently.  Any theoretical work would be similar, for instance calculating orbits according to Newtonian gravity.

With the coming of photography and bigger telescopes built on distant mountains, observational astronomers were attached to specific observatories, carrying out long-term projects that required access to such things.  The development of thermodynamics and spectrum analysis required a different sort of expertise among the theorists, a skill in Physics beyond gravity.  It became more useful to have groups of astronomers working on similar things and talking.

With the rise of Quantum Mechanics in the twentieth century, any astronomer had to absorb more Physics: the theorists to apply the new tools, the observers to design observing programs.  By this time careful work with clocks and cross-wires had been largely replaced by careful work with the chemistry of the darkroom.

In the postwar era, telescopes began to be sited on different continents.  But with the rise of public observatories and widespread air travel, observers from almost any institution could gather cutting-edge data.  And the mass of analysis that had to be done on it meant that a week-long observing run could furnish work for a year.  The number of working astronomers increased enormously.

Digital computers and digital imaging greatly increased the speed of data analysis and data acquisition.  We are now, say, in the 1980-90s, and the role of darkroom chemistry is fading while being able to program a computer has become important.  Papers by such masters as Arlo Landolt and Roger Griffin contain long tables of numbers automatically calculated, though each of them can still discuss particular observations in detail if required.

That is no longer possible.  The flood of data that is automatically collected by surveys has long passed the point where any human could monitor even a small sample, much less vet it all.  Astronomers must devise automatic ways to deal with it and ensure its quality.  Even more, they must figure out what questions to ask of it, and how.

So the solitary, meticulous observer of Sir John Herschel’s day would simply not be interested in becoming an astronomer now.  The theorist who could hold in his head the essence of applicable Physics a century ago, would now be defeated by the explosion of sub-branches.  These days an astronomer works as part of a great team, specializing in one aspect of the work, and is always at a computer.  Astronomers from different ages are different kinds of people.