Hi there.
I'm lucky enough to have been able to work as a professional astronomer - currently, I work as a postdoctoral researcher in the US, working in extragalactic star formation. The usual route to working in astrophysics starts with obtaining a B.Sc. in Physics at Honours level - a 2.2 grade will allow you to start a M.Sc.in Physics, while a 2.1 will allow you to start a Ph.D straight off, without the need to change degree (plus you get more funding!!!).
Usually, you spend 4-5 years as a postgraduate researcher, before writing your Ph.D. thesis. After that, you become a postdoctoral researcher -once you've found a job, you get a fixed term contract at most 3 years in length, where you work away at your chosen field and build up your reputation! Be warned, you have to be very flexible - postdoc jobs are hard to find in Ireland, and more than likely you'll have to go to the UK, Europe or the US (along with your spouse, if you have one!). After a number of postdoc jobs, you start looking for a more permanent job, usually as a lecturer - once you've found a permanent job (otherwise known as tenure), then you're pretty much set up!
Compared to when I started Uni in the early 90's, there 's a lot more options if you're interested in studying/working in astronomy, as virtually all the NUI Unis have now dedicated Physics & Astronomy courses. Here's a few links for Irish University reasearch groups that can provide some more info:
Dunsink Observatory:
www.dunsink.dias.ie/
UCD Space Science Lab:
bermuda.ucd.ie
NUI Maynooth Physics Dept:
physicsresearch.may.ie/main.shtml
UCC Physics Dept:
www.physics.ucc.ie/
UCG Physics Dept:
www.dunsink.dias.ie/links.html
UCD High Energy Astrophysics:
ferdia.ucd.ie/
Armagh Observatory:
star.arm.ac.uk/
QUB:
www.dunsink.dias.ie/links.html
DIAS:
www.dias.ie/index.php?section=cosmic&...;school=astrophysics
If you've any questions, drop me a PM!
Best of luck!
Brian
  