1996/97
Mars Sketch (8)
from CMO #206 (25 August 1998)
-- Distributions of the Observation
Rates of Hk, Id, Iw, Mk and
Mn
in 1996/97 --
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E |
very
apparition we observe Mars continuously about one Earth year during which the
apparent diameter starts from a five second arc, gradually increases to attain
a maximal diameter, and then the ruddy planet gradually goes away. The
apparition is continuous, and so our observation rate should be smooth to keep
pace with this rise and fall. Our case is however not ideal: First the weather
condition is a great annoying factor which troubles us. Second our time is not
so free since we are amateurs. Third we cannot always enjoy the good health
throughout the season, and so on. Our first trial to see the tendency (in #118
p1042) showed that it much depended on personal conditions. We here also pick
out five observers and try again to describe the distributions of their
observation rates in 1996/97. We hope every observer will try the same thing to
read his history.
In the graphs, the curve of rigid line shows the trace of the
apparent diameter δ as a function of the Earth day, while
the curve by dotted line shows δ 2 (δ
squared) which is depicted in such a way that its integral is equal to the
integral of δ (the area bounded by the curve of δ
). A reason to take out the dotted line is that it is of the dimension of area
and it may relay the rise and fall of any unit area inside the Martian surface.
In the 1996/97 apparition, HIKI (Hk)
obtained a total of 83 drawings while ISHADOH (Id) 154, IWASAKI (Iw) 190, MURAKAMI (Mk) 226, and finally MINAMI (Mn) 808, and
thus the numbers are divergent. So to compare we consider the total number of
each observer to be equal to the integral of δ (as well as δ
2
). Then the bar-graph shows comparatively the
distribution of the observation rates as a function of month. Each month starts
from the 16th day of the preceding Month to 15th of the Month.
Roughly, HIKI (Hk) started early and
his peak came before opposition in Feb/Mar. A fall or dip seen in the latter
half was due to his personal reason (he became very busy because of work for a
teacher's union). IWASAKI (Iw) was slower to start but
steady up to opposition, but his pace went down in Apr/May. The peak came in
June. This tendency is also seen in a previous case at p1043 (and also at
p1296). Usually Iw observes much more in the evening,
but in the summer in 1997 the day was longer and the planet ran down to the
south-east, and hence he could not well observe after the eastern quadrature on 23 June.
ISHADOH (Id) usually observes intensively at the period when the
planet is much closer, but this time his distribution look indifferent to the
rise and fall of the apparent diameter, and had a very outstanding peak in
Feb/Mar. But his better part of drawings were obtained
in this period. Because of this peak, his observations in other months of don't
look noticeable, but they show that the observation rates were steadily dense.
He has a tendency to observe densely in a month before opposition (this time in
Dec/Jan; see also the graph at p1298) and this may be a good idea to become
much experienced about the markings before opposition. MURAKAMI (Mk) used to
work in the evening and so rather observe at night as well as when the planet
was at the eastern sky. Even then he made efforts also to watch long the lower
Mars in the early evening this apparition. MINAMI (Mn) was favourable
in the first half and had a peak at the same interval as Id had, but showed a
dip in Apr/May. In the latter half he also felt difficult because the planet
went down lower to the south in the evening.
One thing that is not shown by the graphs is the way how the observers
traced the markings. It is possible to make a similar graph if some does
observe no more than Syrtis Mj, while it is hoped any observer trace all the
angles during a forty day period. At least the five observers here represented
are all adherent to any angle. We finally emphasise therefore that our observations should be done
all along the angles one or twice or more before opposition until we try to
make the frequency graph.
(Mn; while Figs by Ns)
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