1996/97
Mars Sketch (7)
from CMO #205 (25 July 1998)
-- Elysium in March 1997 --
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here review the Japanese observations of Elysium in March 1997 when the Martian
season was near 090°Ls. As reported in CMO No187 p2033 the region was
impressively whitish bright in the afternoon side. From 7 Mar (087°Ls) to 13
Mar (090°Ls) there were obtained a number of observations (every forty minutes)
in
As a good example, we first introduce the observations by ISHADOH (Id)
made on 10 March. His observations started from 13:20GMT and ended at 18:10GMT
on the night and were made in the following way:
Id-076D
10 Mar (089°Ls) ω=231°W
Id-077D
10 Mar (089°Ls) ω=241°W
Id-078D
10 Mar (089°Ls) ω=250°W
Id-079D
10 Mar (089°Ls) ω=260°W
Id-080D
10 Mar (089°Ls) ω=270°W
Id-081D
10 Mar (089°Ls) ω=280°W
Id-082D
10 Mar (089°Ls) ω=289°W
Id-083D
10 Mar (089°Ls) ω=302°W
Elysium was apparent from the outset (Id-076D), but it became
very evident from around Id-079D. In Id-082D, 
Elysium was near the terminator and nearly vanished in Id-083D. Id made
also at ω=300°W on 9 Mar where the situation was the same. On 10 Mar the
phase angle was 07°, and Elysium was at around 4 o'clock local time when
Id-080D (ω=270°W) was made.
Elysium Mons described by Id became whitish bright in the deep afternoon
and hence this phenomenon was caused by such a white orographic
cloud as reviewed in Mars
Sketch (3) in No 201.
Fig. ISHADOH's
drawing (Id-080D) on 10 Mar 1997 (089°Ls)
at ω=270°W showing a very whitish bright cloud at Elysium
At
Mn-332D 7 Mar (087°Ls) ω=248°W
Nj-093D 7 Mar (087°Ls) ω=252°W
Mn-333D
7 Mar (087°Ls) ω=257°W
Nj-094D
7 Mar (087°Ls) ω=262°W
Mn-334D
7 Mar (087°Ls) ω=267°W
Nj-095D
7 Mar (087°Ls) ω=272°W
Mn-335D
7 Mar (087°Ls) ω=277°W
Nj-096D
7 Mar (087°Ls) ω=282°W
Nj-097D
8 Mar
(088°Ls) ω=224°W
Nj-098D
8 Mar (088°Ls) ω=234°W
Nj-099D
8 Mar (088°Ls) ω=244°W
Nj-100D
8 Mar (088°Ls) ω=253°W
Nj-101D
8 Mar (088°Ls) ω=263°W
Nj-102D 8 Mar (088°Ls) ω=273°W
Nj-103D 9 Mar
(089°Ls) ω=215°W
Mn-336D
9 Mar (089°Ls) ω=220°W
Nj-104D
9 Mar (089°Ls) ω=225°W
Mn-337D
9 Mar (089°Ls) ω=230°W
Nj-105D
9 Mar (089°Ls) ω=235°W
Mn-338D
9 Mar (089°Ls) ω=240°W
Nj-106D
9 Mar (089°Ls) ω=245°W
Mn-339D
9 Mar (089°Ls) ω=250°W
Nj-107D
9 Mar (089°Ls) ω=255°W
Mn-340D
9 Mar (089°Ls) ω=259°W
Mn-341D
9 Mar (089°Ls) ω=272°W
Mn-342D
9 Mar (089°Ls) ω=281°W
Mn-343D
9 Mar (089°Ls) ω=291°W
Mn-344D
9 Mar (089°Ls) ω=301°W
Mn-348D
11 Mar (089°Ls) ω=203°W
Mn-349D
11 Mar (089°Ls) ω=230°W
Mn-350D
11 Mar (089°Ls) ω=240°W
Mn-351D
11 Mar (089°Ls) ω=249°W
Mn-352D
11 Mar (089°Ls) ω=259°W
Mn-353D
11 Mar (089°Ls) ω=271°W
Mn-354D
11 Mar (089°Ls) ω=281°W
Mn-355D
11 Mar (089°Ls) ω=291°W
Nj-110D
11 Mar (089°Ls) ω=295°W
Mn-356D
11 Mar (089°Ls) ω=300°W
Nj-111D
11 Mar (089°Ls) ω=305°W
Mn-357D
11 Mar (089°Ls) ω=310°W
Nj-112D 11 Mar (089°Ls) ω=315°W
We
also have other observations among which the following are included:
Mo-054CCD 11 Mar
(089°Ls) ω=250°W
Id-084D
11 Mar (089°Ls) ω=251°W
Id-085D
11 Mar (089°Ls) ω=261°W
Id-086D
11 Mar (089°Ls) ω=271°W
Id-087D
11 Mar (089°Ls) ω=281°W
Mn-358D
12 Mar (090°Ls) ω=216°W
Mn-359D
12 Mar (090°Ls) ω=226°W
Mn-360D
12 Mar (090°Ls) ω=236°W
Mn-361D
12 Mar (090°Ls) ω=245°W
Mn-362D
12 Mar (090°Ls) ω=255°W
Mk-135D
12 Mar (090°Ls) ω=260°W
Id-088D
13 Mar (090°Ls) ω=212°W
Id-089D
13 Mar (090°Ls) ω=222°W
Id-090D
13 Mar (090°Ls) ω=232°W
where Mo=MORITA, and Mk=MURAKAMI.
In the Mo image the afternoon Elysium is bright even though it
was taken in Red. As seen from the example by MURAKAMI, Elysium this time
proved most conspicuously whitish at ω=250°W - ω=260°W. The
observations by Mn on 12 Mar was at
We have described mainly the trend of Elysium, but the region made of Cebrenia was also interestingly bright throughout the
period.
We also note that the afternoon Elysium shows the characteristic aspect
in the Video images taken by HIGA (Hg) on 9 Mar, 10 Mar and 11 Mar. On 10 Mar
at ω=218°W, Elysium looks more whitish and brighter than
Elysium still faced to us. On 17 Mar (092°Ls) at ω=192°W,
Elysium
Mk-141D 20 Mar (093°Ls) ω=186°W
the morning Elysium and Cebrenia were apparent.
Elysium came into sight again in mid-April. The Y-shaped Elysium-Cebrenia region was still light. But the apparent diameter
went down to 12 arcsecs, and we could not catch well
the activity of Elysium Mons. On 23 Apr (108°Ls) at ω=206°W (Mn-554D),
there were seen a few areas of bright spots inside Elysium, but looked somewhat
off-white. Id also recorded on 20 Apr (107°Ls) at ω=241°W (Id-110D) that
Elysium was off-white. A CCD Red image by AKUTSU (Ak)
shows a light Elysium on 22 Apr at ω=235°W.
Around 20 Apr (107°Ls), the morning Elysium and the following area
showed a white-cloud burst as seen visually and as proved by the Video images
by Hg as reported in Sketch
(1) in No 197 (see also No 204). The cloud was thought as the one developed
from the morning mist which covers frequently the morning Syrtis Mj to make it
to be quite blue-greenish in this season.
Finally we record an aspect of Elysium in Feb 1997 from the notes
of the present writer: Elysium was visible from around 5 Feb (074°Ls). Elysium
and Cebrenia were light enough in a Y-shape, and on 7
Feb (075°Ls) at ω=241°W, there was seen an activity inside Elysium. On 8
Feb (076°Ls) at ω=222°W, Elysium was off-white yet, but at ω=242°W
more whitish than Cebrenia. On 10 Feb (076°Ls) at ω=194°W,
Elysium was not white but at ω=233°W became bright. The apparent diameter
was less than
(Mn
: Masatsugu MINAMI)
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