So, you want to be an astrophysicist? Part 1.

You are at university.
Do you like stars, and stuff?

Another rehashed blast from the past

Should you do astronomy as an undergrad? (the following is in part shamelessly cribbed from a colleague's previous freshman seminar for our majors):

Do you like stars and stuff?
If not, you probably should look for an alternative to astronomy, on the general principle that at this stage of life you should at least try to do things you actually like.
If you do, good for you. Now, do you have the aptitude?

• Professional astrophysics/astronomy is not about looking at stars per se (except at occasional star parties, for outreach or as a sideline hobby - although a fair fraction but by no means all astronomers are enthusiastic amateur astronomers). Nor will you need to learn about constellations, or speculate about the meaning of it all, or the origin of the universe, or other sophomoric philosophical issues (except over occasional beer sessions - except for the constellations bit).

  What you will need to do, is at least 75-80% of a physics major (and preferably all of it, physics double majors are a common path, as is just doing an all physics or math/physics path, and adding astro later).
  That's four years of 2 classes per semester, calculus based physics. You will also need at least 3 years of university level calculus, and if you find yourself taking as little math as possible, then your career options will rapidly shut down and you might want to rethink.
  Some computer science or electronic engineering wouldn't hurt, though most of the practical computing you need you will be expected to pick up through self-study. So, you would need, for example, to be able to look at HTML sample code, or a "how to web page", or in a pinch a book, and figure out in few hours or days how to do adequate HTML coding, as a minimum. Most astrophysics types are expected to know one major compiled language (C++ or Fortran most common), several macro/mark-up languages (like TeX/LaTeX, IDL or Perl) and higher level languages as needed.
  Most people find this to be hard work. You should be ready for hard work.

• Do you like to read? 'Cause you'll be doing a lot of it. Books, papers, web pages, class notes; and, whether they admit it or not - science fiction (ok, not all astro types are sci fi fans, just most of them: secretly, open Trekkies, whatever).
  What do I mean by lots? (For an undergrad.) Mean output of a professional astronomer is 3-4 papers per year. Each paper has 30-40 cites to the literature on average. You have to have read those, all of them! Now, if you work in a single sub-field (which is not uncommon) there'll be a lot of overlap between cites in successive papers, but you'll also have to read 2-3 papers for each one you cite. And, you need to keep up with the literature, there are new papers coming out every day... So, we're talking 1-200 papers to read per year.
• Exams: Yep, we have those. Some people can't handle them. Don't know what to do about that. The people who have a hard time with exams include some very brilliant people. Same with essays and projects, some people do well on exams but have a hard time writing coherent text. Different people can't do different things. Don't know what to do about that either.
• Research: It is generally a good idea to try to get into some research if you can, typically the summer after the end of your junior year, earlier if you can. It looks good on a resume, helps you get letters for grad school (if you still want to go after doing summer research), and lets you know if research is the sort of thing you want to do with your life.
  Some people hate doing research when they try it. Better to find out before you spend ~ 5 years in grad school, or more.
  Going to grad school and deciding it is not for you a big opportunity cost, if you find just want to go out and earn money (or a wonderful life experience if you have the luxury to have those).
  Some people hate doing research. You ought not spend your life doing what you hate.
• What university should I go to?
  Well, the one you can. The "best" one if you have a choice.
  Does it help to go to a "name" university (top private, Big high profile State, or a high rep liberal arts college) - you betcha (and the situation is analogous for other countries, I know the deal for some countries, not others).

  What does it buy you to go to a "good" university?
  1) You get a shot at a good education. In the US there are maybe 50-100 universities where you can get a very good education in astrophysics; the other few hundred universities are "good in parts", but your odds go down sharply.
  Ultimately the education you get depends on you yourself taking advantage of the available opportunities, and generally a "good" university offers the opportunities if you will take them.
  2) You get a second look at the next stage, the committees will look twice at people from places they know (and conversely if you do badly, they know too).
  3) At some level you get what you pay for - there is not a perfect correspondance, but there is high correlation. Money buys you resources, time and access. The "good" school need not have the best teachers, but they often offer the best opportunities to learn pro-actively.

  So - the top private universities (Ivy Leagues, Chicago, Stanford, Caltech, MIT) - will give you a structured, superb education, with access to top faculty (half of whom may not care about you). For a price. If you're willing to take advantage of it. And there's significant in-house competition. Not matter how good you are, you're going to meet someone better at those places.

  Big State University: well, they're relatively affordable, they are big, so there's a broad range of courses and people, and they're well enough known that if you do well you'll get a look for grad school.
  The catch - you have to self-motivate, the place is big and you can all too easily vanish. Success at the Big State U requires the student pro-actively search out opportunities and take advantage of them.
  Embed yourself in the department, not the dorm or the frat/sorority. Interact with the faculty, go to talks, talk to people.
  Profs are PAID to be there at office hours, and, without exception, they have a unique weakness, they love talking about "their research".
  Suckers.
  So go bug a prof. Lots, repeatedly.
  Oh, and get good grades and have natural math aptitude. If you do well academically (B+ GPA or higher AND a consistent good performance in the "hard" classes), and if you hook up with people to work with, you're set.
  But, YOU have to take advantage of the opportunities. If you're lucky, someone will reach out to you once, maybe twice, but beyond that it is up to you.

  Liberal Art College: these are small, have fabulous teachers (on average, at the good ones, except when they're fabulously bad), and you can get lots of personal attention.
  A disproportionate fraction of top researchers come out of majors at these places (like Reed, Vassar, Swarthmore etc), and they produce a disproportionate fraction of science majors, compared to their size (US state universities have an appallingly small fraction of science majors, and vanishingly few physical science majors).
  Catch: there a a lot of small liberal art colleges, a lot are mediocre and there are some bad ones... The bad ones can be really, really bad - where they either suck the money out of your pocket and then hand you a meaningless piece of papers, or they really do care, but do not provide the structure or incentive for students to learn enough to go further.

  A bad university, in the physical sciences, is a career end, unless you have exceptional persistence. What to look for at a university, is a sequence of hard calculus based classes - look for advanced electromagnetism, or advanced quantum, with 2 physics prereqs and a high number course numer math dept calculus based prereq.
  A lot of places let this slip, and you get soft, non-calculus based classes filling the major requirement. Fun, but you don't learn the basics you'll need later.
  The US "modular" course structure is particularly bad in this respect (more on that in another thread, but think about how much more in-sequence engineering and other serious professional majors tend to be... I'm biased, I was educated at a UK university. Viva la difference).

• Publishing a refereed research paper as an undergrad always helps, but is not essential to a future career. Getting into a national summer intern/REU program helps, but is not essential. Having good solid grades, and doing well on the dreaded GREs is what matters.