I have added an option to set the center coordinates for my interactive celestial map, so far only for equatorial coordinates. It is still interactive, so you can pan and zoom as well, but having a determined center should come in handy for showing the current sky over a location on earth, or other planets. Which is sure to come as a feature, eventually.
Leaving the fields blank is equivalent to 0h, 0°
Now, with D3.js it would be perfectly possible to update the center location (or any other viewing state, for thet matter) without reloading, I just haven't implementet it yet. That's also still to come.
Check out the documentation in the GitHub repository for all possible settings. The above linked blog page has an interactive form with all the options to play around with. The repository also contains a page named viewer.html with the same function.