96/97 report 005

1996/97 Mars Observation Reports

-- #005 -- 16 Dec 1996 - 15 Jan 1997


.... Five months passed since the onset of our Mars watching in this apparition. On 17 December at 23 h GMT the planet reached the west quadrature, and hence a fourth of the apparition passed. We thus became able to watch Mars from midnight to dawn: At dawn the telescope points to the west. During the one month from 16 Dec 1996 to 15 Jan 1997 the apparent diameter rose from 7.1 arcsecs to 9.1 arcsecs. The Martian season proceeded from 052° Ls to 063° Ls. Last apparition in 1994/95 opposition occurred at 053° Ls, and the excellent three HST images were taken at 063° Ls, and so the present period was comparable with the peak period of the preceding apparition. The central latitude was 18° N in 1995 at opposition but now 24° N down from 25° N in Dec). It will decrease upto 22.6° N in mid-Feb. The phase angle also decreased from 36° to 33° during this period.

.... Received are observations during the period 16 Dec 1996 and 15 Jan 1997 as follows: We include just the observations as reported to us on A4 sized sheets.

      ADACHI, Makoto (Ad)   Otsu, Japan
             5 Drawings  (30 Dec; 13 Jan)  360x31cm speculum

      AKUTSU, Tomio (Ak)   Karasuyama, Tochigi, Japan
            13 CCD Images  (20, 30 Dec; 7, 9, 12, 13, 15 Jan)  32cm speculum, Lynxx PC

      ASADA, Hideto  (Aa)  Kyoto, Japan
             6 CCD Images  (20, 30, 31 Dec; 10, 13 Jan) 31cm speculum, Mutoh CV-04

      HIKI, Toshiaki  (Hk)   Minowa, Nagano, Japan
             11 Drawings  (20, 23, 24, 29, 30 Dec; 4, 8, 9 Jan)  360x16cm speculum 

      ISHADOH, Hiroshi (Id)  Naha, Okinawa, Japan
             19 Drawings  (16, 21, 23-25, 27, 29, 31 Dec; 8, 12 Jan)   530x31cm speculum

      IWASAKI, Tohru  (Iw)@ Morodomi, Saga, Japan                                                     
           14 Drawings  (10-12, 14, 15 Jan)  400x21cm speculum

      MINAMI, Masatsugu  (Mn)   Fukui/Otsu+, Japan
         101 Drawings  (23, 24, 26-31 Dec; 4, 6, 11, 12, 13+,14+, 15+ Jan) 
                                340,400,480x20cm refractor*/ 320,400x20cm speculum+
      MURAKAMI, Masami  (Mk)   Fujisawa, Japan
            40 Drawings  (16, 21-24, 26, 30, 31 Dec; 4, 8, 10-13, 15 Jan)   370x15cm speculum

      NAKAJIMA, Takashi  (Nj)   Fukui, Japan
            29 Drawings  (23, 24, 28-31 Dec; 4, 11 Jan)   340, 400x20cm refractor*

      NARITA, Hiroshi  (Nr)   Kawasaki, Japan
            36 Drawings  (16, 17, 20, 21, 24, 27-31 Dec; 3, 4, 6-13 Jan) 400x20cm refractor

      SCHMUDE, Richard W, Jr  (RSc)  GA, USA                                                         
             1 Drawing  (20 Dec)  250x51cm speculum
                                                   * Fukui City Observatory

.... On 16 Dec 1996 MURAKAMI (Mk) watched the morning M Acidalium at LCM = 330°W (16:40GMT) and ISHADOH (Id) the afternoon M Acidalium at LCM = 043° W (21:40GMT at Okinawa, a westmost island: Opir was not light), and on the other hand on 15 Jan 1997 the evening M Acidalium was watched from Japan, and hence we were to observe nearly whole the surface during the one month. On 20 Dec, HIKI (Hk) observed at LCM = 355° W, and saw the npc purely white and roundish. On 21 Dec (054° Ls), Mk observed Syrtis Mj near the evening terminator and S Sabaeus near the CM starting from atLCM = 314° W to LCM = 333° W three times. A morning mist at Thymiamata and at Chryse was striking. Id also saw the Chryse morning mist thick at LCM = 341° W. Id completely caught S Sabaus and S Meridiani on the day. On 23 Dec (055° Ls), Id observed the evening Syrtis Mj to S Sabaus at LCM = 320° W and 329° W, while Mk earlier saw Syrtis Mj on the day near the CM at LCM = 285° W. On 23 and 24 Dec (056° Ls), NAKAJIMA (Nj) and MINAMI (Mn) worked together at Fukui and observed Syrtis Mj near the CM. We should however say that the central Syrtis Mj is not interesting: It is more interesting to watch the case where Syrtis Mj comes to the afternoon side to pull S Sabaeus in or the case Syrtis Mj is still near the morning limb. Id was successful to observe successively the appearance of S Sabaeus at the morning side as well as the evening Syrtis Mj from 23 Dec to 27 Dec. At Fukui Nj and Mn could observe the appearance of Syrtis Mj from the morning limb successively from 27 Dec to 31 Dec (059° Ls) (and on 4 Jan). It was possible to find a faint tip of Syrtis Mj at LCM = 230° W without use of any Red filter. As our past experience tells us, Syrtis Mj can be found at LCM = 215° W-220° W before opposition.

.... Syrtis Mj is rather bluish in this season at the morning side, and hence may be more observable after the opposition. This period the maria of the southern hemisphere also looked bluish in good contrast with the tint of dark chocolate brown of Utopia. It is rather useless to observe the faint bluish Syrtis Mj by use of any Red or Orange filter. In this sense the CCD image does not produce the real aspect of Syrtis Mj.

.... Mk tried to catch the morning Syrtis Mj several times, and saw it when it appeared from the morning haze at LCM = 246° W on 30 Dec and at LCM = 248° W on 31 Dec, but did not describe its colour. Id watched Syrtis Mj at LCM = 246° W on 29 Dec and at LCM = 239° W at 31 Dec, and recorded that it was covered by a mist. No description of colour however. Hk observed it at LCM = 260° W on 29 Dec and at LCM = 254° W on 30 Dec. ADACHI (Ad) saw it at LCM = 244° W on 30 Dec.

.... At the end of the year (near at 060° Ls) Elysium came into sight, but it was quite dull, as observe by Id, Hk, Mk, Nj and Mn. Just Mn saw a slightly light zone at Elysium at LCM = 214° W on 29 Dec (058° Ls), and Id felt it to be slightly light at LCM = 217° W on 31 Dec. Later on 11 Jan (063° Ls) and afterwards Elysium looked light to the west of the isolated Propontis I at the morning limb combined with the limb haze (as observed at Fukui by Nj and Mn, but earlier on 8 and 9 Jan Hk already checked the same phenomenon). Cebrenia was also usual and dull, but on 29 Dec (058° Ls) it looked slightly light at the western part observed at Fukui from LCM = 204° W and finally at LCM = 272° W it appeared as an off-white light patch (evident through O56 filter also) near the evening terminator. However the area returned normal on 30 Dec and on 31 Dec. Id observed also the region on 29 Dec but mentioned that Cebrenia was not light (while Elysium rather showed up) at LCM = 246° W, and also no description at LCM = 275° W. the apparent diameter was only 7.9 arcsecs at that time. On 30 Dec, Ak took CCD images at LCM = 230° W, 246° W, 267° W and 274° W(the latter two by R light), but the area was normal as observed by naked eyes at Fukui. Cebrenia should be checked this season especially to the north of Aetheria. The Aetheria dark patch was observed by Id (on 29 Dec), Ak (on 30 Dec), Aa (on 31 Dec), Mk (on 31 Dec) and by Nj and Mn at Fukui several times. N Alcyonius was also glimpsed.

.... The new year days the weather was bad, but after 10 Jan the atmosphere became rather stable. We were very pleased to hear that on 10 Jan Tohru IWASAKI (Iw) who has suffered from an ill-health condition started observing.

....As to Alba in question, Mk almost failed to detect anything except that he felt a white spot near Alba on 10 Jan at LCM = 140° W (Mk-043D), while Iw saw a roundish Alba near the CM on 11 Jan (063° Ls) at LCM = 106° W under better seeing as well as Olympus Mons. However on 12 Jan Alba appeared dull to Iw and could not catch it even at LCM = 116° W. At Fukui, on 11 Jan, seeing being moderate, Alba was seen inside a light zone at LCM = 123° W, and succeedingly at LCM = 143° W, it was clearly visible as a rather small roundish light spot near the evening terminator. Olympus Mons was also seen. Tharsis was thicker at its northern part. There was a dark curved belt between Tharsis and Alba to the SW direction. This is a well known aspect observed for example in 1967 and 1982 to be observed more vividly when the planet will be more closer to the Earth. On the night Alba was still visible at LCM = 152° W. Id also observed this trinity of Alba, Olympus Mons and Tharsis together with the dark belt correctly on 12 Jan at LCM = 128° W. At LCM = 119° W, Alba was inside a zonal light area also to Id. Id considered that Tharsis contained the lightness of Candor. Iw also recorded that Candor (+Opir) was light at LCM = 096° W on 12 Jan.

...Another thing we paid attention this time was the evening mist over Chryse: As reported in the preceding issue (#183 p1969), the evening mist over Chryse was observed to be definite and thickest around when LCM = 060° W as the observations from 8 Dec (048° Ls) to 13 Dec (051° Ls) told. It was however observed this time that the mist became at a peak at around LCM = 080° W-090° W as observed from 13 Jan (064° Ls) to 15 Jan (065° Ls) at Fukui. It was possible for the mist to be at higher level than in Dec. Iw observed the mist also on 14 Jan and strongest near at LCM = 088° W, and then weakened. On 15 Jan, Mk watched from LCM = 066° W to 085° W, and pointed out the similar tendency. Ak's successive CCDs on 12 and 15 Jan also show a thickest mist at around LCM = 090° W.

...As to the npc, Id paid much attention this period because he had felt from November or before that it was not usual but slightly dull having sometimes a brownish tint. On 16 Dec he also felt so, but from 24 Dec onwards the npc was usually bright to him (even then he wondered on 29 Dec). SCHMUDE (RSc) on 20 Dec also observed that the npc had an orange-white colour. On the other hand, the npc has always been whitish bright through the refractor at Fukui. The brightness of the npc when the image is small must depend, as also pointed out by Id himself, on the condition of the aluminisation of the speculum, and so this is a difficult problem. (The present writer uses a dull mirror at Otsu which showed a weaker npc when Iw saw the npc to be very whitish bright by his speculum.)

[After completion of this article, we received CCD images from H ASADA (Aa): the images on 20 Dec by R light clearly show the bright npc at LCM = 339° W and LCM = 356° W. The R image on 10 Jan at LCM = 135° W isolated Propontis I at the morning side and Olympus Mons in the afternoon. Alba is faint through R.]

....... We came to know that the BAA Mars Section began to publish an A4- sized one-page report or newsletter every month from November 1996 all written by Richard McKIM, Director of the Section. We have just received (on 20 Jan) three reports, the first one being written on 4 Nov, the second on 3 Dec and the third on 14 Jan. The third report treats the observations during the period 1-31 Dec 1996. Unfortunately we have no time to refer to the reports this time, but will surely do in the future in this column or elsewhere.

....... Next issue will review the observations made during the period from 16 Jan to 31 Jan: We hope to receive any report at the beginning of February. We are sorry to hear and see in TV that a terrible weather struck Europe recently. We had a rather good weather at the end of the last year (contrary to the weather forecast), but now here in Mikuni we are receiving a cold snowy weather as well as a bad stream of heavy oil at the seashore flowed out from a broken Russian tanker.


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