We would like to announce the availability of "Prometheus: Cloud Computing Portal for Computational Optogenetics". This is a web-based portal for PyRhO - a set of tools with a GUI for modelling and simulating opsins in neurons, using Python, Neuron or Brian 2. The main attraction is that all necessary modules and dependencies are already installed and configured (including the Python programming language, commonly used scientific Python libraries, NEURON and Brian2 simulation platforms) and the GUI comes with some pre-loaded values. So the platform can be used immediately. Absolutely no installation or set-up is required, just a web-browser, since the portal is using IPython/Jupyter<https://jupyter.org/> notebook. The portal is available here: http://try.projectpyrho.org/ To simplify things, there is no registration wall at the moment. But please note that the resources we are currently renting from a cloud computing service provider are limited. So please be patient - sometimes it might take more time to execute your job, depending on the number of users running their codes at the same time. A paper describing the platform, including several demonstrations, has been published: Evans et.al: "PyRhO: A Multiscale Optogenetics Simulation Platform", Frontiers in Neuroinformatics (2016): https://www.frontiersin.org/articles/10.3389/fninf.2016.00008/full Best regards, Dr Benjamin Evans, Bristol University, UK Dr Konstantin Nikolic, Imperial College London, UK