Low-resolution differential drift scans of the Moon at 22 microns

Abstract

Differential drift scans were made across the 3-day-old moon at a wavelength of 22 μ with a beamwidth of 2.4 arc min. Measured cold-limb brightness temperatures ranged from 102°K in the equatorial region to 84°K in the southern polar regions. Certain scans were processed to reveal the temperature distribution from the cold limb to the sunrise terminator. The portion of the lunar ‘cooling curve’ that was obtained by this method agrees well with the portion measured by previous investigators who made infrared scans from the sunset terminator into unilluminated regions.