APOLLO Lunar Pointer Tool

lunar pointer tool

This lunar pointing tool streamlines our ability to track targets on the moon. Showing realistic lunar phase and libration, we can see at a glance which targets will be illuminated by sunlight. Around each reflector we have a few small, distinct pointing references that will help us home in on the reflectors. In the view above, the red crosses are lunar reflectors, the red circle indicates that the telescope is now tracking Apollo 15, the orange circle shows Brewster, a pointing reference for Luna 21. Clicking "Slew Telescope" issues commands to the TCC to track the selected target.

One can also use the time incrementing tools to explore the illumination and libration of the moon on other dates, which help in planning future ranging opportunities.

The sky color changes to indicate darkness/twilight/daylight, and the moon turns a darker color when it is below the horizon.

In this view, Apollo 14 and 15 are in the dark, Apollo 11 is just across the terminator, and Luna 21 is in full light. The red mark at lower right indicates which limb is tilted toward us due to libration, its magnitude depicting the degree of tilt (here 7.25°).

The diagram at lower right tells us by how much and in what direction to lead the moon with our laser beam. We must shoot where the moon will be in 1.25 seconds, while looking at where the moon was 1.25 seconds ago. The opening angle between where we look and where we shoot is typically a little more than 1 arcsecond.

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