MOTION PICTURE RING SIGHT USED ON THE MOON DURING APOLLO 15.
PERHAPS THE ONLY LUNAR SURFACE RING SIGHT STILL IN PRIVATE HANDS. FLOWN Maurer DAC (Data Acquisition Camera) sighting ring. Circular metal ring, 1¼ inches in diameter with an optical component at the center. A flat metal "shoe" guide allows the ring to be mounted at the top back corner of the 16mm Maurer motion picture camera. An approximately ½ inch square of white Velcro is attached at the top. Part Number SEB3310031-204 and Serial Number 1051 are engraved around inner metal circular section of the sight. With a Typed Letter Signed by MRS. JAMES B. IRWIN. Plus two sheets copied from the Apollo 15 equipment stowage list and a diagram showing parts and numbers of the DAC camera system including the ring sight.
MRS. IRWIN'S signed provenance letter reads: "The enclosed camera ring sight was flown to the surface of the moon during the flight of Apollo 15. It was used by my late husband James B. Irwin inside the Lunar Module (LM) which was named Falcon. The Data Acquisition Camera (DAC) camera was mounted along Jim's viewing window located at the interior right-hand side of the LM. That camera recorded the undocking of Falcon from Command/Service Module Endeavor, then Falcon's descent past the Apennine Mountains. It captured views of Hadley Rille just prior to the LM's touchdown on the lunar surface. During the lift-off from the moon, Falcon flew directly over the Rille and Jim was able to record some magnificent views of this unusual lunar feature.
The ring sight has the following engravings: "P/N (Part Number) SEB3310031-201, S/N (Serial Number) 1051" on one side and S/N 1051 on the opposite side. As described in the spacecraft operations manual, the ring sight was "an accessory used on the 16 mm camera as an aiming aid when the camera is hand-held. The concentric light and dark circular rings, as seen superimposed on the view, aid the user in determining the angular field of view of the sight. It is attached to the camera by its shoe sliding into a C rail. It is also used on the 70 mm camera."
Additionally, enclosed with this letter is a copy of page 48 from the official equipment listing by NASA titled: "Apollo Stowage List, Mission J-1, CM-112/LM-10, APOLLO 15, August 10, 1971 Final Release, This Issue Documents the AS-FLOWN Configuration." Page 48 contains equipment from "List B" which has items placed inside the Lunar Module prior to the Apollo 15 launch from the Kennedy Space Center on July 26, 1971. The ring sight is the second to last item listed on page 48 and includes the part number, stowage location, and unit weight. This camera ring sight was on the lunar surface for over 66 hours between July 31 and August 2, 1971. It is perhaps the only lunar surface ring sight kept by any Apollo astronaut because it was part of flight equipment slated to stay in the Lunar Module. After the LM crew re-docked with Endeavor, the lunar rocks and other essential equipment was transferred over to the Command Module. The LM was then de-orbited and crashed back into the moon as part of a seismic experiment to understand the composition of the moon's surface. This ring sight was stored out of daylight since 1971 and still retains the concentric rainbow type coloration when light passes through the ring."