Forthcoming 2005 Mars
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The SPC on Grids at λ=235°Ls, 250°Ls, 270°Ls
Masami
MURAKAMI and Akinori NISHITA
|
T |
he
spc has hitherto indicated the Martian south pole, but since around λ=235°Ls its center moves to the direction of Ω=030°W, and so it is not so easy to point out the pole
direction hereafter. To exactly know the axis it is advisable to record on the
image frame the direction of the planet moving out when the motor drive is made
stopped (as usually done by Don PARKER and Yukio MORITA). Here we show the
schematic diagrams of the spc how it is seen deviated from the pole at
particular angles at λ=250°Ls and λ=270°Ls. As to the form and size of the spc (especially
at λ=250°Ls) we referred to
the results of the Lowell Observatory, the Viking data and recent MGS-MOC
images.
NB: The indication p shows
the preceding direction of the movement of the image when the motor drive is
stopped. We depict also the noon line (N-line) by a dotted line. This
shows how we mostly observe the afternoon side at present. The intersection of
the N-line with another dotted line (M-line) is the point where
the Sun shines at zenith (sub-Solar point DS).
