From Richard W SCHMUDE Jr
@. . . . . During the past 4 days (Sep. 6 through
Sep. 10), I have made several polarimetric and
photometric measurements of Mars. The
mean polarization of Mars in the Johnson V-filter was +1.69% which indicates a
general clearing of the dust; however this value is well below the ~+3.0% which
is considered normal (dust free) for Mars at a solar phase angle of 45
degrees. Photometric measurements in the
Johnson V-filter show that Mars is about 0.15 magnitudes brighter than
predicted which is much less than the 0.3 magnitude difference in July and
early August. The B-V value of Mar (Sep.
7 and 10) is 1.56 which is well below the 1.65 to 1.70 value
measured in August. Based on all of the polarimetric and photometric measurements made between Sep.
6 and Sep. 10, I conclude that the dust storm clearing has progressed about
half-way since the peak in July and August.
(
Richard W SCHMUDE Jr
(PGA , USA)
SCHMUDE@falcon.gdn.peachnet.edu