2001 Mars Observation Reports -- #16--
CMO Mars Observations
in the Second Half of September and the First Half of October 2001
from 16 September 2001 (234°Ls) to 15 October 2001 (253°Ls)
based on the article published in CMO #252 (25 October 2001)
Masatsugu MINAMI, Director of the OAA Mars Section
months have passed since the global dust cloud was entrained, while the
apparent Martian surface still remains opaque. The dust-laden atmosphere must
have been much cleaned and the activity must be in the decay phase, but the
usual dark markings do not well show up, possibly because the surface must have
received some fallout of the dust particles which will survive until the landed
dusts will be gradually blown away. Furthermore we sometimes observe that the
surface looks duller as if subsequent minor local dust disturbances still
inject an amount of airborne dust into the atmosphere. At any rate, however, it
is now harder to watch the details since the apparent angular diameter is
already under 10 arc seconds.
We review this time our observations made during the period from
16 September (234°Ls) to 15 October 2001 (253°Ls).
On 16 September, the apparent angular diameter
was 11.9", while it went down to 9.8" on 15 October. The central
latitude went up from 2°S to 10°S. As is illustrated on
a Figure in CMO #237 p2846, the tilt of the central latitude reads around
from 250°Ls in a similar way as in 1986, 1969, 1954 and so we may compare the
present case with the behaviour in those preceding
years, though the angular diameter differs as shown in
the other Figure of the same article.
The phase angle remained near 46° during the present period, and was maximal at the beginning of October (46.3°). The altitude is ascending seen from the NH, and the apparent declination recovered upto -24° 13' on 15 October. Mars attains the eastern quadrature on 30 October at 2h, so that the most preferable observing hour is just around the time when the Sun sets.
HE smaller the diameter, the fewer the observations. However, depending on the weather and the evening chance, more than 100 times of observations were made (100×20 minutes = 33 hours were spent) merely by three persons of ISHADOH (Id), NAKAJIMA (Nj) and TSUNEMACHI (Ts). KUMAMORI (Km) also has more chance to use a 60cm Cass at his office within his working time. Unfortunately MORITA (Mo) could not join this time because of a serious trouble of a worm gear.
BIVER, Nicolas (NBv)
5 Colour Drawings (21, 23 September; 8, 13# October 2001)
300x 20cm speculum / 330x 26cm speculum#
DOMBROWSKI, Philip L (PDb)
1 CCD Image (23 September 2001)
f/25 30cm Meade SCT with an Astrovid
ISHADOH, Hiroshi (Id)
34 Drawings (16 ~ 18, 20, 21 September; 2 ~ 8, 10, 11, 13 October 2001)
530, 410, 340x 31cm speculum
KUMAMORI, Teruaki (Km)
13 CCD Colour Images (20+, 24+, 26, 28 September; 2, 3, 4, 11, 14, 15+ October 2001)
+20cm Dall-Kirkham with a Sony PC-5 /
60cm Cassegrain $ with a Sony TRV-900
MELILLO, Frank J (FMl)
5 CCD Images (26 September; 2, 8, 11, 15 October 2001)
20cm SCT with a Starlight Xpress MX5
MINAMI, Masatsugu (Mn)
75 Drawings (17, 18, 20, 22 ~ 24, 26, 28 September; 3, 5, 8, 13 ~ 15 October 2001)
480, 400, 600x 20cm refractor*
MURAKAMI, Masami (Mk)
18 Drawings (22, 23, 24 September; 7, 11, 12, 14, 15 October 2001)
400, 320x 20cm speculum
43 Drawings (18, 20, 22 ~ 24, 26, 29 September; 3, 6, 8, 14, 15 October 2001)
480, 400x 20cm refractor*
NARITA, Hiroshi (Nr)
26 Drawings (17, 18, 22 ~ 26 September; 2, 3, 11 ~ 13, 15 October 2001)
400x 20cm refractor
PARKER, Donald C (DPk)
6 Sets of CCD Images (24/25 September; 6, 7, 14 October 2001)
f/44 41cm Newtonian equipped with a Lynxx PC
TEICHERT, Gérard (GTc)
6 Drawings (17, 22, 28 September; 10, 11, 12 October 2001)
330, 310x 28cm SCT
TSUNEMACHI, Hitomi (Ts)
31 Drawings (18, 22, 23, 24, 29 September; 2, 11, 13, 14 October 2001)
360x 12.5cm Fluorite refractor
VALIMBERTI, Maurice (MVl)
9 Sets of CCD Images (21, 27 September; 8 October 2001)
f/85 15cm refractor with a TC245 based camera
A. The Yellow Cloud and Dust Disturbances :
The global yellow cloud, made of airborne dust since the beginning of July, looks to have been quite thinner to the extent that some usual dark markings hitherto unknown are recovering. The markings are however not so distinct but quite blurred perhaps because of irregular but vast sedimentation of dust here, there and everywhere. The usual meteorological activity is still scarce perhaps because of the unusual temperature. The dust disturbances however seem still to be raised to obscure or lighten some areas. The following are the reviews of markings in relation to the yellow cloud.
Olympus Mons :
The summit area of Olympus Mons was visually detected by ISHADOH (Id) still as a dark spot on 16 September (235°Ls, day 85) at LCM=188°W & 198°W, on 17 September (day 86) at LCM=169°W & 178°W, on 18 September (day 87) at LCM=174°W, on 21 September (day 90) at LCM=133°W. At
Area of Solis Lacus :
Solis L has not yet recovered. The images made 21 September (day 90) by VALIMBERTI (MVl) cited above are important in this respect; especially the one made at LCM=117°W is comparable with the preceding images on 6 September (cited in #251) by Don PARKER (DPk) (as well as with DPk's following ones on 14 October).
DPk's images on 6 September (day 75) showed a singular
dark segment at Claritas Fossæ
(perhaps the classical Phasis), and MVl's image on 21 September suggests this marking. Furthermore
it shows a shadowy patch preceding Claritas Fossæ whose position may be south of the east end of Valles Marineris. This patch was
caught quite dark by DPk on 14 October (252°Ls,
day 113) at LCM=117°W & 127°W. The patch is however not so conspicuous
visually and looks slightly away from Solis L (or from the centre of Solis L).
On 23 September (day 92), Mn observed at LCM=086°W, 096°W, 106°W, 125°W: At LCM=086°W, there was seen a dusty light belt between Auroræ S and the following dark patch. This can be checked on KUMAMORI (Km)'s image (by a 20cm DK) on 24 September (day 93) at LCM=090°W. On the day Mn observed at LCM=086°W, 096°W, where it was noted a similarity and difference from those aspects in mid-July (these shall be compared in future in a CMO Note with HST's image on 14 August as well as with those made around 23 August). MURAKAMI (Mk) observed also on 24 September at LCM=082°W, 091°W, 101°W and detected a light belt following Auroræ S. On 24 September Mn watched up until LCM=125°W and saw a vastly dusty light region at Memnonia in the morning. TSUNEMACHI (Ts) observed on 23 September (day 92) at LCM=108°W, 118°W, and on 24 September at LCM=108°W and so on, and saw the area including the dark patch and pointed that the following area was light. Mn watched 26 September (day 95) at LCM=065°W, 074°W, 084°W, 094°W and saw the light belt crossing Melas Chasma, and at LCM=104°W observed the morning light area appearing. When the transparency improved, the surface was still lit in a tint of bright yellow.
As noted below, MGS's mosaic images on 24 September (day 94) were released on 11
October: The image concerned however does not show well Phasis
and the preceding dark patch. The light region crossing Melas
Chasma looks transparent because the Valles Marineris is visible,
while the light area at Memnonia looks dusty. We
should note this morning area is a mosaic from the band at 14h LMT. On the same
day (24 September) at
Around S Sabæus :
At Fukui, Mn and Nj (*) watched 3 October (day 102) at LCM=347°W, 357°W, 007°W, 012°W(*), 017°W, 021°W(*) and so on where S Meridiani was faintly detected to the eastern end of the slightly deformed S Sabæus. At LCM=026°W, there was seen a shadowy band down from
HST's image on 4 September (day 73), released on 11 October as noted below, shows the area: S Meridiani is visible, but S Sabæus looks bending since Sigeus P is rather fat and the upper side of the eastern Sabæus is covered by dusty sand. The dark markings are still dull in general on this image.
M Cimmerium :
NBv observed on 21 September (day 90) at LCM=251°W, and on 23 September (day 92) at LCM=222°W, where NBv drew M Cimmerium rather normally. DPk's images on 6 October (247°Ls, day 105) at LCM=196°W map well the band from M Cimmerium to M Sirenum along which a faint band of Valhalla runs. These images also show Propontis I. At
Yellow Storm and Ausonia Australis :
Around from 13 October to 15 October, M Chronium was seen from
B. The South Polar Cap :
The present yellow cloud has been singular in the sense that the first silent germ raised abruptly dust high up in the upper atmospheric layer to make the airborne dust widely and rapidly spread in a younger season and it triggered successively several bright dust resonances near the surface. However the cloud, though quite global and long lived, was not characteristically perfect in the sense it did not invade the polar regions, perhaps because the dust has been scavenged there by the lower-temperature atmosphere of the polar regions. As the tilt of the south pole has now been toward us, the thawing south polar cap (spc) was quite evident to us. On 16 September (235°Ls), the central latitude was 2°S. According to ISHADOH (Id), the spc looked flat until 20 September (237°Ls, the central latitude=3°S), while his drawings on 21 September (237°Ls) show a slightly roundish spc. After an interruption because of weather condition, Id found that the spc had shrunk much and looked quite round on 2 October (245°Ls, the central latitude=7°S). At Fukui, NAKAJIMA (Nj) and Mn observed that the spc was slightly roundish on the southern limb on 24 September (239°Ls, the central latitude=4°S). Especially Nj observed that the centre of the spc was brighter than the both sides at LCM=080°W. On 26 September (241°Ls, the central latitude=5°S) at LCM=065°W, Mn observed that the morning side of the spc looked yellow. Km took clearly the bright spc by a 60 cm Cassegrain on 26 September. Mn observed that the spc was rather large on 28 September (242°Ls, the central latitude=5°S), but looked smaller-sized and quite roundish on 3 October (245°Ls, the central latitude=7°S). Nj suspected 29 September (243°Ls, the central latitude=6°S) that the spc looked completely inside the disk at LCM=050°W. Id depicted the spc clear and definite bordered by a fine dark line on 6 October (247°Ls, the central latitude=8°S). It was roundish bright on 15 October (253°Ls, the central latitude=10°S).
Novus Mons (the Mountains of Mitchel) was detected by the 1977 Viking Orbiter to protrude from the spc like a peninsula at 255°Ls to the direction of (70°S, 330°W), and at 267°Ls it detached from the spc. However another classical observation tells the detachment occurs at around 233°Ls ~258°Ls (see CMO #007 in 1986), and so the Japanese observers were on the alert: Id vigourously tried to check along the perimeter of the spc on 2 October (245°Ls) at LCM=034°W~, on 4 October (248°Ls) at LCM=002°W~, on 5 October (247°Ls) at LCM=355°W~, on 6 October (247°Ls) at LCM=338°W~, on 7 October (248°Ls) at LCM=348°W~, on 8 October (248°Ls) at LCM=321°W~, on 10 October (250°Ls) at LCM=319°W~ and so on, but he was not sure to meet any scene of Novus Mons. We got from Km images obtained by the use of the 60 cm Cassegrain at the Sakai City observatory made on 3 October (245°Ls) at LCM=353°W, and on 4 October (246°Ls) at LCM=344°W, but we are not also sure they show the fragment. Mn had a feeling of the case when he watched on 3 October (245°Ls) around at LCM=357°W and LCM=026°W (as well as on 8 October (248°Ls)), but anyway the suspected part was never bright compared with the spc itself. It is said that Novus Mons is not a mountain but a ditch or trench to bring up a water condensate, so that it was possible for the peninsula to be covered by the sand. Novus Mons is bright even when it lies inside the spc: The HST image on 26 June (185°Ls) shows it inside, and the recent HST one taken on 4 September (227°Ls) also shows the bright tip near the perimeter of the spc.
S MIYAMOTO gave a drawing of Novus Mons detached at 247°Ls in 1971 at LCM=010°W (cited in CMO #007 p0049), and MURAKAMI's TP photo by the use of a 10cm refractor was on the cover of CMO #116 where Novus Mons from LCM=000°W is shown at 262°Ls in 1988. In 1988, Novus Mons began to detach around 239°Ls ~ 243°Ls, and a series of drawings by Mn were cited in an article by T NAKAJIMA (Bulletin of the Fukui City Museum of Natural History, No 38 (1991)).
M MURAKAMI (Mk) took this picture by a refractor of 10cm OG
On 29 August 1988 at 15:24 GMT
(LCM=000°W, central latitude=20°S, 262°Ls, app diam=21.8")
C. Miscellaneous :
KUMAMORI (Km)'s image on 26 September (241°Ls) at LCM=058°W shows a faintly light and
whitish triangular area just to the north of the spc. It
is near Argyre, but possibly may be the legendary Mons Argenteus (silver coloured
mountain). M Erythræum north of it is darker
Don PARKER (DPk)'s images on 24/25 September (240°Ls) at LCM=297°W & 302°W seem to show Deltoton Sinus (triangular bay) which has been long lost. These images also show interestingly M Tyrrhenum detached from the following marking. The same scene seems to be seen on MVl's image made on 8 October (248°Ls) at LCM=308°W, and hence the light streak must be made of a sediment of dust on the surface.
& MGS Images Released 11 October: Without any news
about the dust cloud of the century in the IAUC, the HST did not work at the
onset as well as at the height of the present dust cloud, but the images on 8
August (46 days after the onset) and so on were press released on 11 October,
together with the data obtained by the MGS. As far as we know, the major
newspapers as well as other mass communications in
The maps secured by the Thermal Emission Spectrometer (TES) are interesting: Previously on 6 July Terry MARTIN kindly communicated to us a series of thermal colour charts of Brightness Temperature from 24 June to 30 June to prove the gradual warming which started from the Hellas-Hesperia area (#247 LtE & Web). The colour maps of the TES results released this time are extended to date concerning the following growth of the dust activity and the atmospheric temperature. For example it shows that the whole atmosphere at the opposite hemi-sphere was globally warmed due to the rapid arrival of the airborne dust from our side already on 2 July (day 9). The TES images are still being updated every day at http://emma.la.asu.edu/dustindex.html
We further received from PDb:
Philip L (PDb)
9 CCD Images (2, 7, 10, 12, 21 July; 2, 9, 27 August; 15 September 2001)
f/25 30cm SCT with an Astrovid
PDb's image on 2 July (188°Ls, day 9) at LCM=037°W is still full of dark markings (by use of Wr#25), but other images from 7 July on are all not transparent. The ones on 21 July (day 14) and 27 August (day 65) are taken at LCM=217°W and both show the large dark patch at the western part of M Cimmerium. CT is located just to the north of NY, and so the planet is lower. Use is made of an Astrovid recording on sVHS. Selected frames are grabbed using SNAPPY V4 frame grabber and then stacked using AstroStack (freeware). The composite images are processed using Paint Shop Pro and MaxIm DL software.
he next issue (#253, 25
November) shall review the observations during a one-month period from 16 October (253°Ls) to 15 November 2001
We hope every set of CCD images is emailed in a jpg file with a file name beginning with the observer's name to email@example.com as well as to firstname.lastname@example.org. Drawings are preferred to be sent in an A4 sized format with just one drawing on one sheet.
Reports will be acknowledged if air-mailed to M MINAMI at Mikuni
(ask the mail-address through email@example.com ) .