Hello, I'm aware that not everyone who uses R is an astronomer, and so apologies in advance to those people for the nature of this email. I need to convert right-ascension and declination (RA & DEC) coordinates for an object on the sky into physical pixel positions in a FITS image in R. There is a C library that does this, WCSLIB by Mark Calabretta (http://www.atnf.csiro.au/people/mcalabre/WCS/), however I am unsure how to use it in R. I do not program in C, which adds to the problem. I have created the libwcs.so file and moved it to /usr/local/lib already, and am able to load the library in R using: > dyn.load("/usr/local/lib/libwcs.so") and then check that the function I need is available using: > is.loaded("wcss2p") [1] TRUE My problem now is how to actually use it, as the author of the library does not use R. I was wondering if anyone in the community has used this library before, and if so how? Thankyou in advance, Lee Kelvin -- School of Physics & Astronomy University of St Andrews North Haugh St Andrews KY16 9SS United Kingdom Phone (+44) [0]1334461668 Email lsk9 at st-andrews.ac.uk