Beschreibung:

APOLLO 13 STAR CHART – Apollo 13, LM LO-2 HR, 11 April 70 Launch . Star chart signed. Designed to prepare astronauts piloting the Lunar Module for lift-off from the Moon. SIGNED and INSCRIBED: " Used in training for Apollo 13, Fred Haise, Apollo 13 LMP ." Constructed of two plastic disks with a center rivet to allow the top translucent disk to rotate around the bottom star chart disk. The bottom disk shows the Earth, sun, planets and star patterns, plotted accurately at their positons on the intended Apollo 13 launch date of 11 April 1970. The upper disk is a semi-transparent overlay. The six over lapping circles correspond to the exact viewing limits of the LM onboard telescope. The back of the chart has a square patch of Velcro at the center to allow ease of placement. During training in the Lunar Module simulator, James Lovell and Fred Haise used this chart to perform the procedures required for a lunar lift-off. The chart would confirm observations made through the LM’s Alignment Optical Telescope (AOT). These observations needed to be made within 2 hours of lift-off. The steps involved were looking through the AOT and recording the coordinates of stars visible within the chart’s six circular field of view overlays. The AOT could be moved to any one of the six fixed positions known as detents. The star coordinates would be used with the LM Guidance Computer’s Program 57 to complete the platform alignment. It was critical that this alignment be as accurate as possible so that their rendezvous with orbiting Command and Service Module could be made within strict time and fuel limits. Circular star chart, 8.5 inches in diameter.