#### Sky Navigation

Left drag
  Pan. In the Sin projection, this attempts to rotate the sphere, with north staying vertical on the screen, in such a way that the same part of the sky stays under the cursor position. At low magnifications this is sometimes not possible; if the mouse starts on the sphere and ends up off it the navigation will be jerky.

  The Aitoff and Plate Carée projections act like a piece of paper that can be dragged around in two dimensions in the usual way.

Wheel
  Zoom. Spinning the mouse wheel forwards/backwards will zoom in/out around the mouse position. For this Sin projection this will also have the effect of rotating the sphere to keep North vertical on the screen.
Right drag (CTRL-drag)
  Stretch zoom. Dragging with the right mouse button up-and-right/down-and-left has just the same effect as spinning the mouse button forwards/backwards.
Center drag (SHIFT-drag)
  Frame zoom. Dragging with the middle button to the right (and either up or down) drags out a frame; when the button is released, the plot will be zoomed in to cover (roughly) the area enclosed by the frame. Dragging left (and either up or down) does something like the opposite, you can zoom out using a similar (though not quite the same) mechanism.