APOLLO 13 TRAINING LUNAR SURFACE STAR CHART.
Lunar surface star chart, a circular device, 8½ inches in diameter. Consists of 2 thin plastic discs rotating around a central rivet. The lower disc shows the Earth, Sun, planets and star patterns against a black background. The upper disc is a semi-transparent overlay. The back of the chart has a square patch of Velcro at the center and an inscription in ink by Lovell. Small square of tape over rivet on overlay.
SIGNED and INSCRIBED by LOVELL: "LM Telescope Star Chart used during training, James Lovell, Apollo 13 CDR."
This navigation chart is identical to that carried on board Apollo 13's lunar module Aquarius. It was designed to help Lovell and Haise determine their exact position on the lunar surface by observing the position of stars through the Alignment Optical Telescope. Printed near the edge of the lower disc is "Apollo 13 LM TD+2 HR, 11 April 70 launch." TD stands for touchdown, and this chart would have been most accurate in the two hours immediately after the lunar landing.