Looking for remote desktop app for Mac OS X

I work remotely, and am forced to use an ancient Mac Powerbook that is extremely slow. The software I use for it is Timbuktu, which I hate. The computer I remotely operate also is a Mac, and so knowing there are open-source alternatives out there, I wanted to know if anyone knows of a remote desktop app that would work with Ubuntu 14.04 and let me operate a Mac using OS X. NOT 10.5, I know NoMachine works with Mac 10.5, but my work desktop only uses version OS X and they won't upgade. Any suggestings you all would have that would allow me to use my Ubuntu machine would be gratefuly accepted.