From Richard SCHMUDE, Jr
® . . . . . .Dear Dr Masatsugu Minami:
A set of Mars drawings is enclosed. I tried to get polarization measurements last night but the weather posed a problem. I need almost perfect transparency to obtain polarization measurements.
I have made polarization measurements on several dates this year which were: January 28, March 31, April 1, April 14, June 2 and June 22. The polarization was normal on all of the dates except for June 2 where it was a bit lower (0.5%) than expected. A possible dust storm in the northern hemisphere was imaged around this time and that may have caused the small drop.
A graph showing my photoelectric magnitude measurements is also enclosed. The curve is the predicted magnitude based on the Astronomical Almanac while the points are my V-filter measurements. Dust will cause the brightness of mars to rise. The photoelectric measurements indicate that there was little to no dust in the Martian atmosphere up to June 21.
With Best Regards,
Division of Mathematics and Natural Science,