96/97 report 006

1996/97 Mars Observation Reports

-- #006 -- Martian Surfaces in the Second Half of January 1997


The apparent diameter stepped over the threshold of 10 arcsecs on 25 Jan; The apparent diameter was 9.2 arcsecs but went up to 10.5 on 31 Jan. The Martian season proceeded from 065°Ls to 072°Ls; and now the water vapour is becoming abundant in the northern hemisphere. The central latitude read from 24°N to 23°N. The phase angle was decreasing from 33° to 29°. The Red planet is now seen high up at midnight.

We acknowledge receipt of the following observations:

       AKUTSU, Tomio (Ak) Karasuyama, Tochigi, Japan
             9 CCD Images  (16, 20, 27, 28, 31 Jan)   f/66×  32cm speculum, Lynxx PC

       ASADA, Hideto (Aa)  Kyoto, Japan
             4 CCD Images  (17,20. 28, 31 Jan)  f/37×  31cm speculum, Mutoh CV-04

       HERNANDEZ, Carlos   (CHr)  FL, USA
             7 Drawings  (9 Dec; 18, 19, 21, 23, 25, 27 Jan)  305, 490×  20cm speculum

       HIKI, Toshiaki  (Hk) Minowa, Nagano, Japan
             1 Drawing  (30 Jan)  340×  16cm speculum 

       ISHADOH, Hiroshi  (Id)  Naha, Japan
             8 Drawings  (28, 29, 31 Jan)  530×  31cm speculum

       IWASAKI, Tohru  (Iw) Morodomi, Saga, Japan
             7 Drawings  (16, 22, 27 Jan)  400×  21cm speculum

       MINAMI, Masatsugu  (Mn) Fukui/Otsu+, Japan
           15 Drawings  (16+, 17+, 25, 27, 31 Jan) 400×  20cm speculum+/400×  20cm  refractor*

       MURAKAMI, Masami (Mk)  Fujisawa, Japan
            22 Drawings  (23, 25, 27,~31 Jan)  370×  15cm speculum

       NAKAJIMA, Takashi  (Nj)   Fukui, Japan
            3 Drawings  (25, 31 Jan)  400×  20cm refractor*
       NARITA, Hiroshi  (Nr)   Kawasaki, Japan
           15 Drawings  (16, 17, 19, 22, 23, 25, 26, 27, 30 Jan)  400×  20cm refractor

       NIKOLAI, Andre  (ANk) Berlin, Deutschland
            4 Drawings  (6, 21 Dec; 14, 17 Jan)  500, 330×  10cm refractor

       QUARRA SACCO, Giovanni A  (GQr) 
            & the SGPG (A LEO, S MANNINO & others)  Firenze, Italia
            5 CCD Images  (17, 31 Jan)  f/24×  30cm Cass, ISIS CCD800 with Kodak KAF0400

      MORITA, Yukio (Mo) Hatsuka-ichi, Japan
            17 B&W Photos  (2, 5, 10, 11, 16, 20, 22, 23, 29 Oct; 3, 14, 19, 22, 23 Nov )                                                         f/100×  25cm speculum  TP2415
                                                   * Fukui City Observatory

We first review the recent CCD images by the SGPG: We here count a set of the RGB images as one and furthermore discriminate them by 40 minutes separation, and so the sets on 17 Jan are counted to be 4 here, but they consist of a lot of images as follows: the IR(820nm) images were obtained at ω=199°W, 202°W, 213°W, 223°W and 226°W, R(610nm) at ω=222°W, G(530nm) at ω=206°W, 215°W, 222°W, B(420nm) at ω=219°W and the Tricolour images were at ω=206°W, 215°W and 220°W. These series are interesting in the sense that the shooting began when Elysium was near the CM and by about 40 minutes separations chased impeccably the surface up to when Syrtis Mj was well in the morning. In Colour composites, Syrtis Mj appears from the rear side at ω=215°W, and shows a blue-greenish tint at ω=220°W. Elysium seems to have begun its activity (now 065°Ls), but it should be noted it is quite weaker in the B light, and so we can say it was not Very-Active in the sense of SMITH and SMITH (cf #1434 p1251). In longer waves, however a part of Elysium looks very bright especially in the IR images, and so the area must have been covered by a dusty matter. Cebrenia to the north of the Atheria dark patch is also dusty light. Note that the bright part of Elysium is separated much from Cerberus, and is located westerly rather adjacent to the Atheria dark patch. These images clearly show such dark spots as N Alcyonius and Propontis I. M Cimmerium seems to remain the sameas before. The images on 31 Jan are also excellent: the Colour image was made at ω=039°W. The shape of Nilokeras is clearly produced. Ganges is rather shown in the IR images. Notable is the fact that a thick mist existed near the evening terminator at Thymiamata, and a broad stream of mist hung over to Chryse as seen in the B and Colour images. There was no chase of this phenomenon, but we consider that the evening mist must have behaved as reported in our previous reports (see also below). There is a light spot preceding Hyperboreus L. Ophir is usually light. Finally we should say that there is no disturbance over Thaumasia as is seen in the IR image at ω=043°W (where Solis L is obvious as well as Agathodamon). [We are alluding to the Alert by HERNANDEZ (CHr) (cf LtE) which reports a dust storm over Thaumasia on 29 Jan at ω=131°W. This could and should be checked in the US, because Thaumasia is to the east of Ω=131°W: Don PARKER (DPk) uploaded an image taken on 1 Feb at ω=117°W: How can you detect the dust storm despite the JWr's confirmation (LtE)? ]

Incidentally we refer negatively to the observation by NIKOLAI (ANk) on 14 Jan at ω=238°W: He commented that "Syrtis Major was not recognized. May be this a dust storm?". It is impossible for us to watch the same surface that seen in Europe at the same time, but it sounded dubious: We repeatedly reported how and why the morning Syrtis Mj was faint, and this didn't imply readily any existence of dust cloud. We hope any phenomenon should firstly be chased repeatedly by the observer and should secondly be consulted for his neighbours because the markings remain over their area for some time. Anyway, the images by GQr and his colleagues on 17 Jan deny any such troubles on Syrtis Mj, and also our observations on 31 Jan didn't show any difference on Syrtis Mj as reported below.

From Japan we could observe during the period from the region where the evening M Acidalium was seen to the scene where Syrtis Mj stayed in the morning. On 16 and 17 Jan IWASAKI (Iw) and Mn chased the evening mist which ran up to Chryse. Especially on 17 Jan (066°Ls) Mn observed at ω=028°W at Otsu and saw the evening mist patch over Thymiamata which hung over to Chryse later. This was not different to the image taken by QUARRA (AQr) later on 31 Jan (072°Ls), and also a repetition of the phenomenon reported in #182 p1969 at around 050°Ls (see however #183 p1982). NARITA (Nr) also watched the evening light patch on 22 Jan at ω=037°W. Iw separated Niliacus L on 16 Jan. Nilokeras and Lunae L were rather faint but the southern part of Ganges was seen. On 29 Jan (071°Ls), ISHADOH (Id) made an interesting observation: He detected a thin evening mist which divided Syrtis Mj at ω=335°W. Subsequently at ω=345°W, the mist stayed in a tongue-like shape while Syrtis Mj was dusky. On the same night, MURAKAMI (Mk) started from ω=296°W, and watched every 40 minutes how a mist over Libya which preceded Syrtis Mj was condensed, and at ω=326°W he saw the mist stayed still to the north of Syrtis Mj, but he quitted observing and missed the angle which Id began to observe. Mk however watched the angle previously on 23 Jan (069°Ls) and detected the tongue-like protrusion of the evening mist. The subsequent observations by Mk imply that the evening mist over Thymiamata had an origin from Libya. On 27 Jan Mn watched the same angle as Id, but didn't detect the division of Syrtis Mj by the mist. Hk felt Syrtis Mj weaker at ω=329°W on 27 Jan. Id himself didn't see the division on 31 Jan at ω=329°W. As to the Thymiamata morning mist, Mk chased well and for example he saw a bright core at the morning limb on at 29 Jan (071°Ls) at ω=316°W. The dismal winter sky prevented us at Fukui from observing, but on 31 Jan (072°Ls) we could, though not necessarily sufficient, chase the surface from ω=234°W. We first observed that Elysium was not yet bright enough to be able to call it to be very active through our naked eye, though it was well light through Green filter at ω=244°W. Syrtis Mj was blue-greenish as before. To our surprise, at ω=254°W, the limb side following Syrtis Mj looked very bright even through O56 (560nm) and R60 (600nm). At ω=263°W the brightness decreased but still bright through O56. This situation was new: the morning limb was light always but the area to the north of Syrtis Mj was brighter. This time the bright limb area corresponded to Aria, and quite off-white compared with the dull whitish Hellas. Aria recovered its usual aspect at ω=273°W, but even at ω=297°W, Aria at the CM was quite bright. Id began his observation on the night from ω=290°W, and observed until ω=329°W: He noted that Aeria was slightly bright at ω=300°W, but no more particularly bright. Aria was recorded locally bright also in the last apparition, but as we remember, it didn't show such a brightness as this time at the morning limb side. We should remark that the limb area is not truly in the morning because the phase angle was ι=29°, but we should consider that the morning mist contained much of airborne dust. As to the light Aria, Mk noted already on 30 Jan at ω=297°W and at ω=307°W. He on 31 Jan started observing from ω=285°W, and remarked that the larger area to the north of S Sabaus including Aria is light in a tint of cream up to ω=305°W, and so the day could be extraordinary. He didn't feel the scene at ω=315°W mo more. Id seems to detect Olympia on the day at ω=329°W when Syrtis Mj was nearly dusky.

. . . . The 4th report of R McKIM has not yet reached: In the 2nd report he noted:"I understand that Parker's CCD images confirm the September 18 dust storm over the NPC south edge." We would like to know the reference. If this implies the "dust storm" found by the HST, the "possible NPC-associated dust storm" (current on Internet) on 18 Sept by Don PARKER at ω=017°W is very different to HST's one because even 17°+90° (the morning limb) does not reach 160°W of the west end of HST's matter.

Next issue will be published on 25 Feb in which we will review the observations made during the period from 1 Feb to 15 Feb. Please send them to M MINAMI at Mikuni by Airmail.


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