Having already dedicated a post to Sparky, I feel obliged to dedicate another one to CARA. If you forgot it, Sparky assists the biochemist to assign 2D and 3D spectra of biopolimers. CARA does the same thing in a conceptually different way. You are lucky that there are two alternatives, because they are doing their best to conquer you. Being Sparky freely available, the group behind CARA felt compelled to make the latter freely downloadable too. I have never worked with either, so what can I say about CARA? The name of the author, for example. Rochus L.J. Keller. He has a personal site where he sells his records and distributes sample music tracks. You can verify that Dr. Keller has recorded more records than the Beatles! You can add your comments about the music here below. Here I am writing about NMR, instead.
If you need either Sparky or CARA you probably already know them or one of your colleagues does, therefore you need not my advise. If you are a casual user then both alternatives are perfectly suitable, but you'd better try Sparky first. First reason: it's a lot easier to install, on the Mac at least (the only installation I have attempted). Second reason: CARA's documentation is very rich indeed. It encompassing a wiki, a PhD thesis and the book "The Computer Aided Resonance Tutorial", while Sparky says it all in a few web pages. Both products are well documented, but reading, or even consulting, CARA's documentation takes more time. The web sites are also both well done, but what a difference! The Swiss had more resources to invest than the Californians (it's well known their boss received a Nobel prize in 2002). Only CARA has its own top level domain, and the choice of the name is arguable. Why www.nmr.ch? Does it mean that NMR is all about biomolecules? I guess the simple reason is that the name www.cara.ch was already taken, there was no arrogance. For example, Keller is honest enough to cite the competitor, though in his own way.
He writes: Former XEASY or Sparky users, who are used to manual work with peak lists, might experience a little cultural shock when they start using CARA, because it demands a new way of thinking.
If those who have matured an experience with XEASY risk a shock, what about those who are new to NMR?
If you have read my whole blog, you know how much I criticize interpreted programs and modal programs. This time is different: CARA has been written in C++ and it's mode-less! Does it lead me to nirvana?
There is no need to first learn the complete program, and since each major use-case has its own environment window, there is litte danger to get lost (as for example in XEASY or even Microsoft Word, where one window incorporates each conceivable function, and an inadvertent shortcut execution can lead to nirvana).