2001 Mars Observation Reports -- #13--

OAA MARS SECTION

Mars Observations
in the Second Half of July 2001
from 16 July 2001 (196Ls) to 31 July 2001 (205Ls)
based on the article published in CMO #249 (10 August 2001)


by Masatsugu MINAMI, Director of the OAA Mars Section



T

HE global yellow cloud stays longer than expected (while the great dust storm in 1956 was made thinner within twenty days or one month). So the usual season may not work at present, but the season reached 200Ls on 22/23 July. During the period from 16 July (196Ls) to 31 July (205Ls), the angular diameter went down from 19.1" to 17.2". The central latitude went up from 7.3N to 7.4N, but went back to 7.0N at the end of July. The phase angle increased from 26 to 35. The apparent declination was still going down.

  THIS time we received still a lot of observations from the following observers:

AKUTSU, Tomio (Ak) Tochigi, Japan

6 Sets of CCD Images (16, 20, 27, 30 July 2001) f/70 32cm spec with a Teleris 2

 

ASADA, Tadashi (As) Munakata, Fukuoka, Japan

5 Sets of CCD Images (21, 23, 27 July 2001) 30cm spec equipped with a Lynxx PC

 

BIVER, Nicolas (NBv) Versailles, France / Noordwijk, Nederland

10 Colour Drawings (12, 14, 16, 20, 21, 24, 28, 30 July 2001)

330x 26cm speculum/300x 20cm speculum

 

CAVE, Thomas R (TCv) Long Beach, CA, USA

4 Drawings (14, 18, 19, 27 July 2001) 400x 33cm speculum

 

Di SCIULLO, Maurizio (MSc) Coconut Creek, FL, USA

1 Set of CCD Images (31 July 2001) 25cm Excelsior Optics E-258

 

FALSARELLA, Nlson (NFl) Sao Jose do Rio Preto - SP, Brasil

1 CCD Image (25 July 2001) 20cm speculum + AVA ASTROVID 400

 

GRAFTON, Edward A (EGf) Houston, TX, USA

2 Sets of CCD Images (28, 31 July 2001) f/60 35cm Celestron SC with an ST6

 

HEATH, Alan W (AHt) Long Eaton, Nottingham, UK

2 Drawings (12, 13, 14, 19, 23, 27, 30 July 2001) 160, 200x 20cm SCT

 

HIKI, Toshiaki (Hk) Nagano /Naha, Okinawa, Japan

18 Drawings (20#, 21##, 23, 24, 30 July 2001)

430x 22cm speculum

420x 25cm SCT, 430x 35cm SCT, 480x 40cm spec (chez WAKUGAWA)#

420x 25cm SCT, 330x 21cm spec, 400x 31cm spec (chez ISHADOH)##

 

ISHADOH, Hiroshi (Id) Naha, Okinawa, Japan

7 Drawings (16, 23, 26, 27, 31 July 2001) 290, 340, 400x 31cm speculum

 

ISHIBASHI, Tsutomu (Is) Sagamihara, Kanagawa, Japan

2 Colour Images (16 July 2001) 31cm f/6.4 spec, Fujichrome 400F

 

KUMAMORI, Teruaki (Km) Sakai, Osaka, Japan

5 CCD Colour Images (19, 20, 23, 29July 2001)

20cm Dall Kirkham with a Sony PC-5 / 60cm Cassegarain with a Sony TRV-900

 

MELILLO, Frank J (FMl) Holtsville, NY, USA

1 CCD Image (21 July 2001) 20cm SCT with a Starlight Xpress MX5

 

MINAMI, Masatsugu (Mn) Naha, Okinawa, Japan

96 Drawings (16~19, 20#, 21#, 22**, 23~31 July 2001)

420, 530x 25cm spec

420x 25cm SCT, 480x 40cm spec (chez WAKUGAWA)#

480, 600x 40cm spec (chez Isao MIYAZAKI)**

 

MOORE, David M (DMr) Phnix, AZ, USA

3 Sets of CCD Images (18, 22, 27 July 2001) f/40 36cm Cass with an Astrovid 2000 video camera

 

MORITA, Yukio (Mo) Hiroshima / Okinawa, Japan

23 Sets of CCD Images (15, 20**, 21**, 22, 24, 25, 26, 27 July 2001)

35cm SCT** / f/50 25cm speculum equipped with an ST-5C

 

MURAKAMI, Masami (Mk) Kanagawa / Okinawa, Japan

17 Drawings (16, 20#, 21##, 23, 30 July 2001)

320, 400x 20cm speculum

420x 25cm SCT, 430x 35cm SCT, 480x 40cm spec (chez WAKUGAWA)#

420x 25cm SCT, 330x 21cm spec, 400x 31cm spec (chez ISHADOH)##

 

NAKAJIMA, Takashi (Nj) Fukui, Japan

25 Drawings (19, 22, 23, 25, 26, 28 July 2001) 400x 20cm refractor*

 

NARITA, Hiroshi (Nr) Kawasaki, Kanagawa, Japan

9 Drawings (16, 20, 23, 24, 30 July 2001) 320,400x 20cm refractor

 

NISHITA, Akinori (Ns) Fukui / Okinawa, Japan

6 CCD Colour Images (20#, 25, 26 July 2001)

35cm SCT #

f/190 20cm refractor*equipped with an Apogge AP7p

 

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

5 Sets of CCD Images (18, 30, 31 July 2001) f/36 41cm Newtonian equipped with a Lynxx PC

 

TAN, Wei-Leong (WTn) Singapore

17 Sets of CCD Images (17, 18, 21, 23, 24, 29, 30 July 2001) f/16 28cm SCT equipped with an ST-7E

 

TEICHERT, Grard (GTc) Hattstatt, France

3 Drawings (21, 22, 25 July 2001) 330, 310x 28cm Schmidt-Cassegrain

 

TSUNEMACHI, Hitomi (Ts) Naha, Okinawa, Japan

80 Drawings (20#, 21##, 22**, 23~31 July 2001)

420, 530x 25cm speculum

420x 25cm SCT, 430x 35cm SCT, 480x 40cm spec (chez WAKUGAWA)#

420x 25cm SCT, 330x 21cm spec, 400x 31cm spec (chez ISHADOH)##

480, 600x 40cm spec (chez MIYAZAKI)**

 

VALIMBERTI, Maurice (MVl) Victoria, Australia

1 Set of CCD Images (24 July 2001) f/80 15cm refractor with a TC245 based camera

 

Sakai City Observatory

* Fukui City Observatory

The Yellow Cloud :

  The yellow cloud thickly covers the whole of the Martian surface (except for the polar regions), and at present there is no sign of subsiding. On 31 July, 38 days had passed since the first dust burst occurred. We write so as 31 July (38 days).
  Receiving a phone call from DOBBINS (
TDb) about the occurrence of the dust storm, HEATH (AHt) however thought M Cimmerium and M Sirenum were still visible on 14 July (21 days) at ω=201W, and 19 July (26 days) at ω=176W. Note that because of the veiling by the storm even KUMAMORI (km)'s image by a 60cm Cass on 19 July does not show any particular dark markings at ω=020W. This implies that the deformed part corresponding to the western part of M Cimmerium darkened since 3 July (10 days) (see MORITA's images at p3071 of #248) still remained dark (veiled of course by the global yellow cloud). MOORE (DMr) produced images on 27 July (34 days) at ω=225W where the patch still shows up.

  In mid-July, there were observed in Japan two rather bright dusty streaks around the Solis L region reminiscent of the 1973 dust streaks. On 16 July (196Ls, 23days) MINAMI (Mn) checked them at ω=064W, 074W, 084W, 094W and so on, and thought these were the same as DMr observed already on DMr on 8 July (15 days) at ω=068W (as reported in #248). The images made by TAN (WTn) in Singapore on 17 July, 18 July (25 days) also show these streaks. These were observed also on the occasion of the CMO Okinawa Meeting on 20 July (eg Mn=064W): NISHITA (Ns)'s ccd image at ω=067W by the use of a 35cm SCT well shows the two streaks (#248 p3067 and the CMO Web). On 31 July (38 days), Di SCIULLO (MSc), D PARKER (DPk) and GRAFTON (EGf) reproduced the bright images of the dust streaks at ω=119W, ω=131W and ω=142W respectively. The dust over there must be constantly stirred up or there must be a thick fall-out. (In 1973, MINAMI observed the doubled streaks similar the ones observed this time on 16 October at ω=063W, but they were quite deformed on the following day 17 October 1973 at ω=063W and hence the streaks were not stable and it was apparent that they were floating. At those days the central latitude was 17S.)

 

Activity of the North Polar Hood :

  The north polar hood (nph) has been very active (since 2 July?), and for example for several days 13 July (20 days)~15 July (22 days) it was observed here that the portion of the nph to the north of Ascrus Mons looked bulged up. On 16 July (23 days) the brim-side of the nph following M Acidalium was very bright. Particularly on 17 July (197Ls, 27 days) we observed an extraordinarily bright oval on the brim; to the extent that we have never seen such a brightness: At ω=055W, Mn in Okinawa noticed at the morning side of the nph a brighter spot while it came up near the CM at around ω=094W, though it was less brighter then. It was however very conspicuous around ω=074W: the bright matter looked as if spouting out from the nph to the SW direction so that the border of the nph showed a gap there. On the night after observation, HIGA (Hg) visited Mn's observing place (quite near his place) and told that he had also noticed the bright oval on the Video monitor and assured it was very white because it was also seen bright through the blue light on the 3ccd Video monitor. WTn in Singapore produced images at ω=082W~089W on the day, but his processing lessened the B light and so the conspicuous spot is not so clearly shot.

  On 19 July (26 days) also the nph was active, and on the occasion of the CMO Okinawa Meeting on 20 July (27 days) the activity was a topic of conversation: The nph looked consisting of two patches, and TSUNEMACHI (Ts) observed a bright blow-out from the nph to the west of M Acidalium at ω=050W by the use of a 40cm spec (chez WAKUGAWA) and at the succeeding sessions HIKI (Hk) made detailed sketches at ω=054W, and 064W. Ts confirmed again it at ω=069W. We should also note that the B and G images of MORITA (Mo) on 20 July at ω=037W show a sharp projection spike from the nph at the morning side. On 21 July (28 days) Hk saw a weaker behaviour at ω=064W, that was not conspicuous while the evening side of the nph was rather brighter.

  In response to the activity, the area to the east of M Acidalium was variable: On 21 July (28 days), Mk (chez ISHADOH) and Mn (chez WAKAGAWA) observed by coincidence at ω=021W and noticed that the area between Deuteronilus and the dark border of the nph was rather light (km's image on 19 July at ω=020W and ASADA (As)'s R images on 21 July at ω=010W already showed Deuteronilus faintly). On 22 July (29 days) Ts and Mn (with Id and Hg) visited Isao MIYAZAKI's observatory (at Gushikawa, Okinawa) and used his 40 cm Newtonian to observe the area: there was some dusty streams in the desert and the area showed a complex as if another faint dark marking existed to the east of M Acidalium.

  Mo who returned home from Okinawa produced ccd images at ω=023W~047W on 22 July where the complex is shown. On 23 July (30 days), however the area became simpler: Ts first noticed easily Deuteronilus at ω=010W by the use of a 25cm spec at Naha, and Mn confirmed it in a succeeding session at ω=015W. The form of Deuteronilus is very normal on Ts's drawing made at ω=030W. At the same time, a blow-out of the nph to the direction of M Acidalium was witnessed. Later we received images of WTn from Singapore at ω=016W~027W where Deuteronilus is very apparent. As's R image on 23 July at ω=019W also shows Deuteronilus. The image of Deuteronilus was visible to the Orient until 26 July (33 days).

  The nph itself was considered normally thick or thin: The northern part of M Acidalium was seen through the nph several times on 20 July at ω=025W (by Mn), on 21 July (200Ls) at ω=035W (by Hk), ω=036W (by Mn), on 23 July at ω=035W (by Mn), and on 24 July at ω=035W (by Mn), ω=040W (by Ts): Such a shadowy segment was often observed inside the nph.
  The
nph continued to be active: On 28 July (35 days) the morning patch to the north of M Acidalium was intense. The nph looked also complex on 30 July (37 days) and 31 July (38 days); on 30 July at ω=310W a portion to the NW of Utopia showed a shadowy area inside, and on 31 July, ISHADOH (Id) observed at ω=282W that the nph was subdued with a shadowy segment inside. From the opposite side seen from the US, however, the nph was thick with a bright brim bulged to the direction of Ascrus Mons (cf Figures: MSc at ω=119W).
  Finally we note that the band adjacent to the perimeter of the
nph was quite dark this period in general as if the dust cloud avoided the water-vapour barrier of the north circumpolar region. See the dark fringe of the nph in any of B and G images in the case of the ccd images.

Tharsis Ridges and Olympus Mons :

  From the Orient, Olympus Mons and Tharsis Montes faced to us as interesting dark spots in mid-July. On 16 July (23 days), Olympus Mons was first clearly witnessed by Mn at ω=084W (one Martian hour after Sunrise) and observed until ω=130W by ISHADOH (Id). On 20 July (27days) at ω=069W, Ts detected Ascrus Mons (one hour and forty minutes after the Sunrise). On 31 July (38 days), the American observations aforementioned show clearly them as dark spots. Ascrus Mons looks however comparatively less dark than in mid-July.

Noachis :

  As reported in the preceding issue, MOORE (DMr) shot a strange zigzagged dark band in Noachis on 15 July (22 days). On 18 July (25 days) at ω=314W, he again shot the region and showed the area of the eastern S Sabus. At the Oceania and Orient Noachis came into sight from 23 July (30 days): At ω=356W, S Meridiani looked to appear but the eastern end of M Erythrum to its east was much darker. On 24 July (31 days), Ts noticed at ω=331W that the pseudo-S Sabus was still present. On the same day, VALIMBERTI (MVl) in Australia gave good images at ω=333W. On 25 July (32 days), Mn observed at ω=315W and obtained similar results: At ω=327W, the eastern part of S Sabus was dark near the CM while the western part was washed out. A dark line from Utopia running westward was also seen. On the same day at ω=325W, NISHITA (Ns) who had returned home from Okinawa took a set of good images at Fukui. The scene was also shot by TAN W.-L (WTn) on 29July (36 days) at ω=333W, 343W, and on 30 July (37 days) at ω=319W~326W. At Naha, Okinawa, Ts on 30 July (37 days) chased the region until ω=332W (though Naha is located to the east of Singapore by about one hour and half.)
  We finally note that Depressiones Hellespontic became visible from 24 July; it showed a dark blue (not veiled) tint adjacent to the
spc and its morning cloud.

 

The South Polar Cap and Its Morning Cloud :

  The south polar cap (spc) was thin at the southern limb, and followed by a thick persistent morning cloud: The cloud stayed always on the limb often with a sharp and dark boundary, and so it was often confused with the spc. At around 200Ls, the snow line of the spc is usually at 58S~60S if seen from around 000W , and at around ~62S from the opposite 180W. Hence if the central latitude is 7N, we can expect a thicker spc on the southern limb, and so it is possible for the spc to have shrunk much faster. The morning cloud, apparently made of water vapour, looks also out of usual season: At the same season in 1986 (a round 5 July 1986) such a cloud was seldom observed, and as well it was not conspicuous in 1969 (around 1 August 1969).

 

End of July :

  In Japan on 30 July (37 days) AKUTSU (Ak) observed at ω=255W, and Mk at ω=301W and so Syrtis Mj appeared on the morning side. WTn in Singapore made images upto ω=326W. In Europe then, BIVER (NBv) took a drawing at ω=050W showing a faint M Acidalium. AHt in UK observed at ω=079W (he says Seeing awful) suspecting Solis L. On 31 July (38 days), in the US, as cited before, the area from the clear Olympus Mons to the unclear Solis L region faced to them. At Naha, we observed from ω=260W to 309W (then it looked to rain) on 31 July: The western part of M Cimmerium was dark, and Utopia was variable adjacent to the active nph. Ts pointed out the colour difference between Syrtis Mj and Utopia. The morning cloud at the south circumpolar region was visible with its dark fringe as well as Depressiones Hellespontic. There were still seen several dusty currents at Libya and inside Hellas at the end of July.


ERRATA :   We are sorry for the mistakes in the list at page 3068: The dates of observations by Don BATES should be read 8, 9 July and those by Nicolas BIVER should be 12, 14 July.


T

he next issue (#250) shall review the observations during a fortnight period from 1 August (206Ls) to 15 August 2001 (214Ls). CMO #251 shall be published on 25 September 2001.
We hope every CCD image 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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