Some years ago I posted an essay about employment in the field of astronomy. These notes are an updated and streamlined version of that rather verbose effort; however, if you want more details and explanations, the old version is available at Old Advice .
This is intended for people who are in PhD programs in astronomy (and those who are about to start) who intend to make astronomy their paying job. That is, you want to be paid to do astronomy. I include in this classification those who spend most of their time teaching at a four-year institution, but who get in some resarch; I exclude from this category someone like a sysadmin at an observatory who does no personal research in the field.
You will get many forms of career advice, from general statements all the way to specific and personalised workshops on CV-writing. This advice comes mostly from people who have been successful in getting jobs in astronomy and of course should be listened to and respected. But these successful people are subject to survivor bias, and their experiences will not necessarily match yours. To balance that I present these observations and advice from someone who has not been notably successful.
You've been successful so far, going through several levels of school with good marks and getting into grad school. But now you will be leaving the school system and going out on your own. You may receive advice and even help; but those who provide the advice and help don't have to live with the results (or lack thereof). It's up to you.
The basic fact of astronomy as a career is that people do it because they like to do it. It's not a way to fortune or fame; people enjoy the practise of it. That means there will always be fewer jobs in the field than people willing to take them. With a few exceptions (to be mentioned below) it's a buyer's market, and you're a commodity in good supply.
The basic structure of the field is hierarchical: one professor with a permanent job will have many students; one PI with a grant will have one or more (temporary) postdocs, one or more (temporary) students. To some degree the non-academic permanent jobs (in observatories, for instance) make the balance more even, but there are always more students and temporary employees than permanent jobs.
Together, the basic fact and the basic structure of the field generate the basic statistic: roughly one-third of astronomy PhDs will wind up in permanent jobs in the field. Now, you'll see various numbers quoted for the fraction of PhDs who wind up with jobs. Almost all can get a first postdoc. But most, something like two-thirds, will not be employed in the field permanently. So your grad school, while recruiting, can quote encouraging numbers based on initial jobs; but if you manage to stay in the field, you're the exception. You will have been better than your peers at getting a job.
A few years ago a study of historical trends in astronomy production and employment (available in eprint), concluded that something under half of all astronomy PhDs would find a permanent job in the field. I think that's too high, since the estimate was based on only US data, and from my observations the United States is a net importer of astronomers. More recently, data on the American Institute of Physics statistics web site showed 173 PhDs granted in 2018, while there were only 37 astronomy faculty positions filled. I think 21% is too low, since it did not count faculty at non-PhD granting institutions or observatories. I'll stick with my estimate of one-third for now.
In the best tradition of astronomical nomenclature, I'm about to name an effect after someone who technically did not discover it and may in fact have had nothing to do with it.
During my time at CTIO I remember one person who had been serving on the Time Allocation Committee (TAC) talking about the various observing proposals he'd been reading. I believe it was Malcom Smith, former director of CTIO. Anyway, it went something like this: ten to fifteen percent of the proposals were obviously excellent and would get all the time they needed no matter what process the TAC went through. Another ten or fifteen percent were so poorly thought out or simply impossible that they'd never get any time. The middle seventy to eighty percent were all good enough to be worth observing time, but so close in merit that there was no clear way to rank them. Unfortunately, with the telescopes oversubscribed about three to one, most proposals had to be cut somehow. The eventual choice depended a great deal on the TAC members, their backgrounds and views of the science, and on chances of timing and other details.
So here is Smith's Law restated for the astronomical job-seeker: "Ten to fifteen percent of astronomy PhDs are so clearly outstanding that they will have no trouble getting a job. Ten or fifteen percent are so unsuited to the career that no one in the science will ever hire them. The remaining seventy to eighty percent are so close in capability and merit that their eventual fate depends on chance, timing and other factors."
"Other factors" can include many, many things. The single most important factor, and one which I've not seen addressed at all in this context, is what you choose to work on: your subfield within astronomy. I'll go into that in a bit of detail below.
As a PhD student your focus, almost to the exclusion of all else, is completion of the thesis. But the actions, skills and qualities that lead to a successful thesis are not identical with those giving you the best chance at a postdoc position; and these in turn are not identical with those leading to a permanent position.
A PhD project must satisfy rather strict criteria: it must be scientifically significant, at least enough to be worth doing; require enough skills and effort to be worth a PhD; and still be small and self-contained enough to be completed in a few years with identifiable results. Unfortunately, many good PhD projects lead nowhere. The subject area may be unpopular or even moribund on any higher level; the skills and background required may have no particular application to further or other work. Thus there is at least a potential source of friction between a supervisor and student over what exactly is meant by a useful project.
Most postdocs are rather narrowly focussed. There is a specific job to be done, sometimes amounting only to reducing a pile of data already acquired. People are hired based on a specific background or set of skills. If you don't have this background, you won't be hired. But a permanent job requires much more: the ability to initiate and organise your own research program, attract funding, publish lots of papers, attract notice. You can be the ideal candidate for some postdoc positions and have no hope at all of getting anything permanent.
So in order to raise your chances of getting a permanent job, you need to structure your grad school and postdoc efforts around that end. It may mean sometimes a slower, more difficult time with the thesis, and possibly more difficulty getting a postdoc, or accepting one with features you're inclined to think of as drawbacks. Remember, if it were easy, most people wouldn't fail at it.
The three most important choices you make come at the very beginning of your reseach career, when you know the least and are in the worst position to make them: where you do your graduate work, who is your thesis advisor, and what is the field you'll work in.
I won't say much about choosing a school or an advisor (you'll receive plenty of advice on those matters), apart from noting that a school with a broader range of subfields allows more flexibility. You can be flexible early in your studenthood, much more so than later.
Choosing your field is more important than any student I've met realises.
The most important point is this: the field must be FUNDED. To increase your chance of employment you need to choose a field at which people are throwing money. I can see two different strategies for this: the conservative, in which you choose a field that is established and neither expanding nor contracting greatly; and the speculative, in which you look for the next big thing. As examples, I would put planetary nebulae and cataclysmic variables in the conservative category: there's no big explosion of interest in them at the moment, but plenty of work going on. Being conservative means you're not increasing your odds of employment greatly; on the other hand, at least there are jobs to shoot for.
A some years ago I would have put things like exoplanets in the speculative category. Catching the next wave is a monumentally difficult thing to do deliberately (you can, of course, fall into it by chance). You need to see it coming in advance, before most people--and that means when you've just begun your studies and are least equipped to do so.
I've spent some time at astronomical conferences asking established, knowledgeable people about attractive fields to get into. Even phrasing the question as, "What would you do if you were starting your PhD again, but knowing what you now know about the science?" got no answers. It's such a difficult question, while being at the same time so important, none of them would commit themselves even informally!
There are two other features of your possible subfield to consider. The first of these is the ease of PUBLISHING. The hard fact is that, when applying for any position, employers will look at the number of your publications first. If there aren't enough you won't make the first cut, and the quality and size will be irrelevant. So you need to choose a field in which you can get papers out in at least moderate numbers. I can't give specific figures, and anyway they change with time.
At the same time, you need to be aware that papers with many authors do not have the same weight as few-author papers, and employers do look at this point. Of course later they will examine the quality and impact of your research but first they will look at how many papers there are and how many authors are on each. There is a very strong trend in astronomy for more authors on each paper, amounting even to a sociological shift in how astronomy is done. I don't know how search committees will wind up handling this.
Conversely (this is a comment made by another astronomer) if you show a strong tendency to write single-author papers, employers may suspect that you work on something no one else is interested in, or thinks important; or that you are personally hard to work with, or even antisocial.
The next point (and not entirely separate from everything else I've said) you need to be VISIBLE. Some fields just get more attention than others, even with similar levels of funding. Big questions are visible (which is one reason for the popularity of cosmology). And if you use the latest, biggest equipment for your work you will by definition be visible. Consider that departments everywhere tout their record of using the Keck or VLT, HST, or the most advanced computers.
Of course the biggest and best can do things impossible or impractical for smaller and older installations, and so their projects will contain more cutting-edge research. If you dream up a project that requires many square metres of mirror diameter and advanced instruments, or better yet something not yet even built, you will probably be doing a good job of advancing the science. Still it is true that, apart from the science you do, the tools you use to do your work impress people. Though everyone I've spoken to concedes that good work can be done, and is done, on smaller and older equipment, it has far less visibility.
Even when you're looking for a permanent job, in which you need to demonstrate independence and original ideas, your field is extremely important. Institutions are very reluctant to stake out a position in a field entirely new to them, preferring someone who can connect with their current faculty. And, of course, you will be expected to bring in funding, which brings us back to the need to specialise in a well-funded area.
From my own observations, it appears that theorists are in general harder to employ than observers; and that instrumentalists, of whatever sort, are always in demand. (Of course skill in making high-tech things is looked on highly outside of astronomy proper; see Alternate Plans.)
At some point late in your graduate studenthood you'll be looking for a job. Unless you slide into one by word of mouth or being in the right place at the right time (which happens, though I can't say how often), you'll be perusing the job ads and sending out applications. One thing to remember is that, unless you're in the top Smith's Law category, you're a replacable commodity. Put aside your pride and get ready to be treated thoughtlessly.
These will be mostly in the AAS Job Register, sometimes in the RAS email service, occasionally in other publications. They generally specify the fields of interest and the expected background of the candidates. They can be written quite strongly and in detail, or give only a few vague features plus an escape clause. The latter can be of the form "complementing and extending present research areas" or the more general "any areas will be considered."
The unfortunate truth is that there is no way to tell just what the prospective employer does want or will hire at the end. A general sort of desirability criteria with "any areas" escape clause can in practice mean that they will accept only a one specific type; or a very detailed and specific list can be thrown out the window and someone quite different hired.
As a commodity, the (middle Smith's Law) job-seeker has no leverage. He or she is faced with the guessing game: do they mean what they say, or not? Should I take the time and effort to construct another hand-crafted, carefully-researched job application package, individually signed by the author, for this position that fits me perfectly, and for which they may decide to take someone quite different; or this other one, which doesn't fit me well, on the chance that I'll impress them anyway; or either, knowing there's a chance that they already have someone in mind and won't even look at me? (An ad appeared on the RAS email listing, for a UK university, with a deadline date of that same day. That's pretty obvious, and they should have been called on it. But who was in a position to do so?) Unfortunately, many times the search committee itself doesn't really decide what they want until very late in the process or changes its mind along the way. So even if you can get a definite idea (say, from a friend in the department) of what they think they want at the time of the application deadline, it may have changed before the hiring decision.
I've been advised, by people no longer in (this part of) the job market, to apply for everything. That is, I should look at not only the places I'd fit, but also those that would require the specifications in the ad to bend significantly. At first look, that seems to be the only way out, the venerable "carpet-bombing" approach. But having served on a Search Committee once I can say that an application not obviously directed toward that particular institution stands no chance of being considered. And it takes time to customise one's work. By my estimate, applying for a wide range of positions but far fewer than all possible, I've spent between one-fourth and one-third of my productive time for years doing nothing but applying for the next job. (Multiply that by the number of graduate students and postdocs in our science and the loss of actual science time is staggering.) A true carpet-bombing would take so much time that each application would be empty: there would be no science to put in it.
Maybe I've given the impression that astronomy employers are overtly cruel, or deliberately thoughtless. That's not really the case. As people, I find astronomers very friendly and helpful. But of all the skills and talents that will help you get employed in the science, administrative competence does not appear. You'll get a lot of interest if your research is timely and/or of high quality; you'll definitely increase your employment chances with each new grant you pick up. An example of excellent management, however, is unpersuasive and will remain unremarked on your CV. And it shows. My experience with job-hunting threw up many examples of disorganized processes with sometimes contradictory instructions, missed deadlines, and seeming disinterest on the part of the Search Committee members. Administrative skill was often lacking.And it indicates where, in their priorities, the Search Committee lies: at the bottom. They can get away with it only because of the basic fact of astronomy as a career (as noted above).
Going back to the beginning: you're a PhD student, just starting out on research. You may or may not take my advice laid out above, but in any case you probably will not get a permanent job in astronomy. Have an alternate plan. What will you do if you can't or don't become an astronomer?
Do some planning and preparation in detail. That will be hard because your environment is all geared toward astronomical research: how to do that well, and what science is involved. Thinking of doing something else as anything other than "something else" is difficult. You have to get out of that environment to make a good alternate plan. You are justified in spending time on alternatives. I mean a significant amount of time: 10% surely, I would say up to 20%; which is quite reasonable, given that the chance you'll need it is more like 60-70%. You should know what you'd do tomorrow if all of astronomy suddenly vanished. You should have your application forms ready for the teacher certification course, if your plan is to teach in secondary school; you should have your seaman's papers ready, if you're going to run away to sea.
I'm not advocating being a defeatist. There is a reasonable chance you'll never need the alternative plan, and possibly a larger one that you'll decide to do something different if and when the time comes. But having the plan in place will drastically reduce the anxiety caused by setbacks in research and by job rejection letters. It is worthwile to have some part of yourself not bound up in a single effort, so you don't feel like a total failure if something goes wrong.
(On a speculative note: it is technically possible to do astronomical research without actually being employed in the field. In a way, most astronomers are doing something else to pay the bills, like teaching or support of telescopes, and do their research in the minority of their working time. But without an institutional affiliation it's going to be hard to seem credible; and who's going to pay page charges?)
I have three points to make before I end up this essay: the matter of teaching, size of teams and a small bit of encouragement.
Skill and experience in teaching are just not important for research astronomy job-seeking. Of course that statement will raise all sorts of cries of dissent; but it's true. Most of the academic jobs in the AAS Job Register do not even call for a teaching statement, while all call for a description of your research. Some call for the teaching statement (I have this on inside authority) but weight teaching not at all in the selection process. Most call for the ability to attract outside funding and all look at it carefully. Given the choice between someone who has years of classroom experience, with ideas and enthusiasm but no grant; and someone who has a grant for a postdoc and three grad students, but only a brief TA; only a very small number of Search Committees that would choose the first one. (There are some, I know, but they're rare in the Job Register.) Teaching experience and skill may help you in a close selection, but it's not going to be a major factor overall.Second: astronomy is increasingly being done by large teams, sometimes very large. What does this mean for the job hunter? I'm not completely sure. It may mean that you need to specialise more precisely in your skills; it's certainly harder to stand out in the crowd; and of course you have to be able to coordinate and communicate more completely than in a smaller group. But it's the direction we're headed, so you do need to think about it.
Finally: this is a terribly discouraging essay. One-third chance to follow your dream can sound awfully small. But it's a far better chance than most writers or actors have of making a living, far better than Humanities PhDs have of actually getting paid for their knowledge; a better chance than an Ensign has of ever becoming the Captain of his or her own ship. You do have a good shot at it. Good luck.