2001 Mars Observation Reports -- #16--

OAA MARS SECTION

CMO Mars Observations


in the Second Half of September and the First Half of October 2001
from 16 September 2001 (234Ls) to 15 October 2001 (253Ls)
based on the article published in CMO #252 (25 October 2001)

 


Masatsugu MINAMI, Director of the OAA Mars Section



 

F

OUR 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 (234Ls) to 15 October 2001 (253Ls).

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 2S to 10S. As is illustrated on a Figure in CMO #237 p2846, the tilt of the central latitude reads around from 250Ls 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.

T

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 (10020 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) Noordwijk, Netherlands / Versailles, France#

5 Colour Drawings (21, 23 September; 8, 13# October 2001)

300x 20cm speculum / 330x 26cm speculum#

 

DOMBROWSKI, Philip L (PDb) Glastonbury, CT, USA

1 CCD Image (23 September 2001)

f/25 30cm Meade SCT with an Astrovid

 

ISHADOH, Hiroshi (Id) Naha, Okinawa, Japan

34 Drawings (16 ~ 18, 20, 21 September; 2 ~ 8, 10, 11, 13 October 2001)

530, 410, 340x 31cm speculum

 

KUMAMORI, Teruaki (Km) Sakai, Osaka, Japan

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) Holtsville, NY, USA

5 CCD Images (26 September; 2, 8, 11, 15 October 2001)

20cm SCT with a Starlight Xpress MX5

 

MINAMI, Masatsugu (Mn) Fukui, Japan

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) Fujisawa, Kanagawa, Japan

18 Drawings (22, 23, 24 September; 7, 11, 12, 14, 15 October 2001)

400, 320x 20cm speculum

 

NAKAJIMA, Takashi (Nj) Fukui, Japan

43 Drawings (18, 20, 22 ~ 24, 26, 29 September; 3, 6, 8, 14, 15 October 2001)

480, 400x 20cm refractor*

 

NARITA, Hiroshi (Nr) Kawasaki, Kanagawa, Japan

26 Drawings (17, 18, 22 ~ 26 September; 2, 3, 11 ~ 13, 15 October 2001)

400x 20cm refractor

 

PARKER, Donald C (DPk) Miami, FL, USA

6 Sets of CCD Images (24/25 September; 6, 7, 14 October 2001)

f/44 41cm Newtonian equipped with a Lynxx PC

 

TEICHERT, Grard (GTc) Hattstatt, France

6 Drawings (17, 22, 28 September; 10, 11, 12 October 2001)

330, 310x 28cm SCT

 

TSUNEMACHI, Hitomi (Ts) Yokohama, Japan

31 Drawings (18, 22, 23, 24, 29 September; 2, 11, 13, 14 October 2001)

360x 12.5cm Fluorite refractor

 

VALIMBERTI, Maurice (MVl) Viewbank, Victoria, Australia

9 Sets of CCD Images (21, 27 September; 8 October 2001)

f/85 15cm refractor with a TC245 based camera

 

$ Sakai City Observatory

* Fukui City Observatory

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 (235Ls, day 85) at LCM=188W & 198W, on 17 September (day 86) at LCM=169W & 178W, on 18 September (day 87) at LCM=174W, on 21 September (day 90) at LCM=133W. At Fukui, Mn checked it 17 September (day 86) at LCM=148W, and KUMAMORI (Km)'s image made on 20 September (day 89) at LCM=133W also suggests the stain. The LCM at 188W implies that Olympus Mons is quite close to the afternoon limb, but its local time is just at 12:40 LMT, and so it is now difficult to watch the afternoon Olympus Mons even if it is covered by ice-condensates. At LCM=133W, it is near the CM, but its LMT is 9:00. The summit may barely be visible as a dark stain on the morning area even if the atmosphere is clear, and so the visibility of the summit does not necessarily prove the presence of the dust cloud sea round the foot. On 20 September (day 89), Mn observed a light broad streak to the east of Olympus Mons (at LCM=140W), and so the heat carried by the dust may still prevent from making ice cloud even at the evening side. We finally note that VALIMBERTI (MVl) produced a good set of images on 21 September (day 90): Those at LCM=149W, 165W show clearly the Olympus Mons dot.

 

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=117W 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 Foss (perhaps the classical Phasis), and MVl's image on 21 September suggests this marking. Furthermore it shows a shadowy patch preceding Claritas Foss whose position may be south of the east end of Valles Marineris. This patch was caught quite dark by DPk on 14 October (252Ls, day 113) at LCM=117W & 127W. 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=086W, 096W, 106W, 125W: At LCM=086W, there was seen a dusty light belt between Auror 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=090W. On the day Mn observed at LCM=086W, 096W, 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=082W, 091W, 101W and detected a light belt following Auror S. On 24 September Mn watched up until LCM=125W and saw a vastly dusty light region at Memnonia in the morning. TSUNEMACHI (Ts) observed on 23 September (day 92) at LCM=108W, 118W, and on 24 September at LCM=108W 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=065W, 074W, 084W, 094W and saw the light belt crossing Melas Chasma, and at LCM=104W 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 Fukui we observed the area around Arsia Mons was well shadowy at the morning side ( LCM=096W by Mn and LCM=101W by NAKAJIMA (Nj)), while MGS's image of Arsia Mons at 2 PM is much weaker than the others. We should note also that DPk's image on 14 October at LCM=127W shows that the area at 110W was around 10h LTM.

 

Around S Sabus :
  At Fukui,
Mn and Nj (*) watched 3 October (day 102) at LCM=347W, 357W, 007W, 012W(*), 017W, 021W(*) and so on where S Meridiani was faintly detected to the eastern end of the slightly deformed S Sabus. At LCM=026W, there was seen a shadowy band down from S Meridiani. ISHADOH (Id) caught 4 October (day 104) S Meridiani vaguely at LCM=002W & 014W. However it was lost when the seeing condition was broken, and so he detected no more than the eastern part of S Sabus on 7 October. KUMAMORI (Km)'s image on 4 October (day 104) at LCM=344W suggests a presence of S Meridiani. BIVER (NBv) observed on 13 October (day 112) at LCM=022W, 041W, and on 16 October (day 115) at LCM=358W and depicted rather completely S Meridiani and S Sabus.
  HST's image on 4 September (day 73), released on 11 October as noted below, shows the area: S Meridiani is visible, but S Sabus looks bending since Sigeus P is rather fat and the upper side of the eastern Sabus 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=251W, and on 23 September (day 92) at LCM=222W, where NBv drew M Cimmerium rather normally. DPk's images on 6 October (247Ls, day 105) at LCM=196W 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 Fukui, M Cimmerium came into sight around from 13 October: The western part looked fat just like a head of the sperm whale. Km's images show the aspect of M Cimmerium on 11 October (day 110) at LCM=275W & 284W, and on 14 October (day 113) at LCM=243W: These suggest well that the storm has considerably subsided and so already the decay phase has begun.

 

Yellow Storm and Ausonia Australis :
  Around from 13 October to 15 October, M Chronium was seen from Japan and some brightness of the 'continents' was witnessed. The above-cited
Km's images on 11 October (day 110) at LCM=275W, 284W, and on 14 October (day 113) at LCM=243W show a bright complex belt from Hellas eastward to Eridania: These areas were the place where the near-surface local dust disturbances were seen. We must be aware that Ausonia Australis is the place that is considerably bright at this season even if not dusted aloft. The afternoon Hellas was seen from Japan at the beginning of October: It looked like a large bright mouth from LCM=300W to LCM=355W (by Nj & Mn). Already DOMBROWSKI (PDb) showed this on 23 September (239Ls). MVl's series of images on 8 October (day 107) at LCM=308W, 323W, 330W, 334W, and 338W give good shots of Hellas.

 

  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 (235Ls), the central latitude was 2S. According to ISHADOH (Id), the spc looked flat until 20 September (237Ls, the central latitude=3S), while his drawings on 21 September (237Ls) 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 (245Ls, the central latitude=7S). At Fukui, NAKAJIMA (Nj) and Mn observed that the spc was slightly roundish on the southern limb on 24 September (239Ls, the central latitude=4S). Especially Nj observed that the centre of the spc was brighter than the both sides at LCM=080W. On 26 September (241Ls, the central latitude=5S) at LCM=065W, 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 (242Ls, the central latitude=5S), but looked smaller-sized and quite roundish on 3 October (245Ls, the central latitude=7S). Nj suspected 29 September (243Ls, the central latitude=6S) that the spc looked completely inside the disk at LCM=050W. Id depicted the spc clear and definite bordered by a fine dark line on 6 October (247Ls, the central latitude=8S). It was roundish bright on 15 October (253Ls, the central latitude=10S).

 

  Novus Mons (the Mountains of Mitchel) was detected by the 1977 Viking Orbiter to protrude from the spc like a peninsula at 255Ls to the direction of (70S, 330W), and at 267Ls it detached from the spc. However another classical observation tells the detachment occurs at around 233Ls ~258Ls (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 (245Ls) at LCM=034W~, on 4 October (248Ls) at LCM=002W~, on 5 October (247Ls) at LCM=355W~, on 6 October (247Ls) at LCM=338W~, on 7 October (248Ls) at LCM=348W~, on 8 October (248Ls) at LCM=321W~, on 10 October (250Ls) at LCM=319W~ 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 (245Ls) at LCM=353W, and on 4 October (246Ls) at LCM=344W, but we are not also sure they show the fragment. Mn had a feeling of the case when he watched on 3 October (245Ls) around at LCM=357W and LCM=026W (as well as on 8 October (248Ls)), 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 (185Ls) shows it inside, and the recent HST one taken on 4 September (227Ls) also shows the bright tip near the perimeter of the spc.

 

  S MIYAMOTO gave a drawing of Novus Mons detached at 247Ls in 1971 at LCM=010W (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=000W is shown at 262Ls in 1988. In 1988, Novus Mons began to detach around 239Ls ~ 243Ls, 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=000W,  central latitude=20S,  262Ls,   app diam=21.8")

 

  C. Miscellaneous :

 

  KUMAMORI (Km)'s image on 26 September (241Ls) at LCM=058W 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 Erythrum north of it is darker now.
  Don PARKER (
DPk)'s images on 24/25 September (240Ls) at LCM=297W & 302W 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 (248Ls) at LCM=308W, and hence the light streak must be made of a sediment of dust on the surface.


  HST & 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 Japan neglected. The mosaic MOC images such as those made on 31 July and 24 September were also uploaded on 11 October in: http://www.msss.com/mars_images/moc/10_11_01_dust_storm/index.html. They say the images by the MOC have 'allowed the planetary scientists to pinpoint the actual location of places where dust was being raised, and see it migrate and interact with other Martian weather phenomena and surface topography', and thus went to insist that the MGS Scientists tracked the perfect storm on Mars. It is however the MOC looking down always at the 2 PM lane window can never watch the morning area where the dust disturbances usually start. We should say the dawn area must have been watched to find how (not necessarily where) the subsequent dust disturbances could be raised. How can one say then that the 'scientists' perfectly captured this opportunity of the century? The case of the disturbance on the northern hemisphere around theria (witnessed this time at the beginning of July) was quite rare to be observed and should be said first of all more attractive than the subsequent disturbances at the usual Claritas-Ddalia area. At any rate, several subsequent disturbances were not those of triggering the yellow cloud but those of being triggered by the yellow cloud blanket.
  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:

DOMBROWSKI, Philip L (PDb) Glastonbury, CT, USA

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 (188Ls, day 9) at LCM=037W 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=217W 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.


T

he next issue (#253, 25 November) shall review the observations during a one-month period from 16 October (253Ls) to 15 November 2001 (272Ls).
  We hope every set of CCD images is emailed in a
jpg file with a file name beginning with the observer's name to vzv03210@nifty.com as well as to cmo@mars.dti.ne.jp. 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 vzv03210@nifty.com ) .


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