Organization of Lunar Orbiter Frameson the Dvds

Organization of Lunar Orbiter Frameson the DVDs

Charles J. Byrne

January 15, 2011

Lunar Orbiter frames are assembled from a series of framelets. The frames of the medium-resolution camera typically contain 26 or 27 framelets. The frames of the high-resolution camera typically contain 87 framelets, and are universally split into three subframes, each containing about 29 framelets.

The titles of the files are of the form LO5-202H1, which is read “Lunar Orbiter mission 5, high-resolution frame 202H, subframe 202H1” A medium resolution frame is LO5-202M, read as “Lunar Orbiter 5, medium-resolution frame 202M”. Each exposure produces a medium-resolution frame and a high-resolution frame, with the same number (as above). The exposures are grouped into sites (such as V-49; read as mission 5, site 49). The DVDs do not always include all frames of a site, but are limited by the framelets supplied by USGS, Astrogeology Branch.

In each DVD, there are all of the supplied frames and subframesof each site, except for those where 8 exposures were taken. These are on two or more DVDs designated by letter suffixes (for example, Site V-46A, Site V-46B, and Site V-46C). Sites may be combined on a single DVD if space permits.

In each DVD, there are two copies of each frame or subframe, a full resolution .tif file and a reduced resolution .jpg file that is printable at 300 pixels per inch, 7.5 inches long.

A file entitled Gallery.doc contains a photographic index of all the frames and subframes.

The orientation of the frames depends on whether a mission’s orbit is near-equatorial or polar and whether the target is near side or far side. On these DVDs, each frame or subframe is oriented so that North is toward the top and East is to the right, for matching with the usual maps. As a result, the calibration strip for these images may be on the bottom edge. This is a different convention than is followed on the USGS web site, but is arranged for convenience in interpretation and comparison with typical maps.

An accompanying file on this CD, FrameLog.exl, lists the frames and subframes that have been reassembled. This document lists the first and last framelets assembled into each image, the width of the image in pixels (all are 16550 pixels in height), the number of framelets, and the settings used to reverse GRE nonlinearity. A comment column contains notes on some images.

The processing of the framelets supplied by USGS and the process of reassembly is described in SoftwareReport.doc on this CD.

The location of each frame can be found in “Guide to Lunar Orbiter Photographs” by Thomas P. Hansen of the Langley Research Center, NASA SP-242, 1970. In that book, each frame is plotted on a Lunar Aeronautical Chart (LAC) or Apollo Intermediate Chart (AIC).