The measurement of lunar altitudes by photography—II. Some measurements on the lunar straight wall

Measurements of shadows cast by the lunar Straight Wall are corrected, where possible, for systematic errors and relative altitudes are obtained. All known sources of error are taken into account to compute the most probable error in a result, which is commonly ±10 per cent of the altitude. The results from the photographic method are compared with visual estimates. It is shown that the top of the Straight Wall is level to within ±100 m. For several different shadow lengths, the greatest relative altitude is near to the centre of the Wall, and is of the order of 400 m. The mean relative altitude of the Straight Wall is 300 m for short shadows and 380 m for long shadows.