There are quite a few open source projects in astronomy, but in my experience there is a tremendous amount of code that is squirrelled away as it is difficult to reproduce and entrenches peoples positions. I have mixed feelings about this in general, as I understand the incentive structures, but I do wish in general some of the sub fields were a bit more open. I do think things are getting better in general.

Also I fully agree with the "codes" rant.

Source: working professionally in the field for 4 years.