96/97 report 004

1996/97 Mars Observation Reports

-- #004 -- 16 Nov. - 15 Dec. 1996


This is a fourth report in the present apparition based on the observations made during the period from 16 November to 15 December 1996: The season then proceeded from 038° Ls to 051° Ls including the interesting periods when the MORITA phenomenon was observed over Elysium in 1993 (at 039° Ls), and when a burst of white cloud was observed over Alba last apparition (at 051° Ls). The apparent diameter moved from 5.9" to 7.1" arc and the image gave us an impression that the diameter really became a bit larger. The latitude of the sub-Earth point was from 24° N to 25° N and was deepest. The phase angle was from 36° to 37° (if rounded up): Really the value 36.5° was a maximum, and hereafter it will decrease. This makes a great difference to the case for example in September to October 1992 when the angle went up to 43° with an apparent diameter of 7" arc.

We acknowlegde receipt of the following observations this time:

      AKUTSU, Tomio (Ak)   Karasuyama, Tochigi, Japan
             8 CCD Images  (21, 29 Nov; 3, 7, 8, 9, 11, 14 Dec)  32cm speculum, Lynxx PC

      ASADA, Hideto  (Aa)  Kyoto, Japan
             6 CCD Images  (16, 24, 28 Nov; 2, 11, 15 Dec)  31cm speculum, Mutoh CV-04

      CAVE, Thomas R (TCv)  CA, USA
             3 Drawings  (23 Oct; 9, 10 Nov)  400, 550, 660× 32cm speculum

      HIKI, Toshiaki  (Hk)   Minowa, Nagano, Japan
            16 Drawings  (28 Nov; 2, 3, 6, 7, 11, 12, 13, 14, 15)  360× 16cm speculum 

      ISHADOH, Hiroshi (Id)  Naha, Okinawa, Japan
             4 Drawings (24, 26, 28 Nov; 8 Dec)   530× 31cm speculum

      MINAMI, Masatsugu  (Mn)   Fukui/Otsu+, Japan
            55 Drawings  (16, 23, 25 Nov; 2, 3, 11+,12+, 13+, 14, 15 Dec) 
                               340,400× 20cm refractor*/320× 20cm speculum+
      MURAKAMI, Masami  (Mk)   Fujisawa, Japan
            12 Drawings  (24, 25, 29 Nov; 1, 2, 3, 8, 9, 11 Dec)  370, 270× 15cm speculum

      NAKAJIMA, Takashi  (Nj)   Fukui, Japan
            13 Drawings  (16, 23 Nov; 15 Dec)  340, 400× 20cm refractor*

      NARITA, Hiroshi  (Nr)   Kawasaki, Japan
            1 Colour Photo (26 Nov)      f/270× 20cm refractor
           14 Drawings  (15,21,22,24,25,27,29 Nov; 1-3, 8-11, 14 Dec) 400× 20cm refractor

      WARELL, Johan  (JWr)  Uppsala, Sweden
            2 Drawings  (3, 11 Nov)  330, 400× 16cm refractor

                                                   * Fukui City Observatory
Notice of the conjuction of the HST activity with the Japan area on 29 Nov was cited at the top of CMO #180 and further forwarded in detail by MURAKAMI especially to AKUTSU, MIYAZAKI, NISHITA and MINAMI by e-mail and to HIGA, HIKI, ISHADOH, MORITA by fax, and to ISHIBASHI and NARITA by phone. Out of them, we hear however that no more than AKUTAU (Ak) and MURAKAMI (Mk) were successful at the very moment: Ak took a CCD image at LCM=163° W and Mk a drawing at LCM=165° W (Mk observed from 17: 20GMT to 19:30GMT and tried also to take the sketches at LCM=143° W, 155° W, 174° W, but no good because of poor seeing). NARITA (Nr) only at LCM=194° W. ISHADOH just waited.

This period we observed the region where Syrtis Major was near the CM (on 16 Nov) to the similar region where Syrtis Mj was near the evening limb (on 15 Dec). Presently at the time of the western quadrature (17 Dec), we can watch the planet long just after the mid-night to the dawn.

1) The morning Syrtis Major was observed on 23 and 25 Nov, and NAKAJIMA(Nj) and MINAMI (Mn) had an impression that Syrtis Mj was not dark until late morning contrary to the images by the red light CCD, and maybe faintly bluish in contrast with the area of Utopia and the southern Maria; the latter being fully dark. Especially the dark band of the npc was clear from the end to the other end. Really Syrtis Mj appeared bluish on 25 Nov even at LCM=247° W and 257° W.
[Note Added: After a completion of the present article we received a report From Id and an FD from ASADA (Aa) both on 24 Nov: Syrtis Mj was obscure at LCM=245° W by Id, while seen seen at the morning limb at LCM=228° W through R60 light (by use of the Mutoh CCD camera).]

2) In 1993 at 039° Ls, MORITA discovered and photographed a burst of cloud over Elysium, and the same season came around in this period. On 25 Nov the area of Elysium was visible near the CM but looked very faint and appeared not bright. The season was 043° Ls. No other positive observations here, and so we temporally consider that no burst occurred this year. Just on 3 Dec at LCM=155° W, Elysium was seen light at the morning limb.

3) As December came in, we welcomed the season when in 1995 ISHADOH found the fine fissure of Rima borealis (on 17 Jan 1995 at 047° Ls: cf #155 p1555), but the size of the apparent disk at the present time is too small to detect. Just we could see the shadows of the dark fringe of the not-glossy npc and the shadowy Propontis area. Maybe shown by the HST images.

4) We also faced to the season when Alba was particularly whitish bright last apparition, and HIKI (Hk) for example observed the region on 6 Dec (048° Ls) at LCM=127° W, but it was not clear. Mk also tried to check it but in vain. Just the season 050° Ls was not compatible with the area of Alba from the Japan side this year. Tempe was repeatedly observed by Hk and Mn, but not particularly light.

5) The evening mist over Chryse was watched interestingly on 11, 12 and 13 Dec (050 - 051° Ls) at Otsu: The north of S Sabaeus became slightly misty (at LCM=006° W) and then the mist looked to extend over Thymiamata to Chryse as the planet rotated and maybe to Xanthe (at LCM=036° W) but no more, and the mist became thicker and thicker as the area became compact near the evening terminator. It was the thickest and the most whitish evident at around LCM=065° W. It was seen still at LCM=084° W. Mk already observed this phenomenon on 8 Dec (049° Ls) at LCM=066° W, and confirmed it on 9 Dec at LCM=056° W and 066° W. Hk also saw the area on 11 Dec at LCM=082° W, and observed on 12 Dec at LCM=063° W and then on 14 Dec at LCM=054° W and 062° W that the area was clearly light near the terminator. In 1994 the region was not seen from Japan at the same season, while in Dec 1994/Jan 1995 at about 040° Ls, the similar phenomenon was observed but less evident.
[Note added: David GRAY directly informed us that he had observed already the whitish bright Chryse at the afternoon side at the end of this November by use of a 42cm Dall - Kirkham. See LtE.]

6) As to the UK observation of the phenomenon at Candor-Ophir (cf LtE), Mk e-mailed and faxed the alert to the main observers in time, but no positive report of confirmation was obtained. For example Hk observed on 7 Dec at LCM=097° W, 108° W and 118° W, but the area looked normal, just lighter when nearer the evening terminator. Mk also tried earlier but made no comment.

7) Through the whole period the southern limb always appeared to be thinly whitish bright. It sometimes thickly concerned with Hellas and Argyre, but not always. In 1994 at this season, the similar aspect was observed, but in 1993, the central latitude being at around 05° N, the situation was more complexed. The present phenomenon must be due to the presence of a thin atmospheric matter at the spr at this season.

8) Dark markings were usually seen. Hk observed intensively in Dec, and watched Solis L and Lunae L as well as Nilokeras to the darkest M Acidalium. Aurorae S was also fully dark. On 15 Dec Nj and Mn alternatively watched M Acidalium coming from the morning limb to the CM.

9) It is notable that AKUTSU (Ak)'s CCD images were successful to reveal the npc from 29 Nov and 3 Dec, and on 9 and 14 Dec he shot M Acidalium many times. His Int image seems to show the Chryse mist at the evening limb for example on the images on 11 Dec at LCM=067° W, but not so clearly.
[ASADA (Aa) also took CCD images at LCM=064° W on 11 Dec through B460 in which Chryse near the terminator was shot faintly light but not so apparent.]

CAVE (TCv)'s drawings were made on 23 Oct at LCM=142° W, on 9 Nov at LCM=266° W, on 10 Nov at LCM=274° W. On the latter two Syrtis Mj appeared dark since he used a Red filter. Hellas was bright at the morning limb, and Libya also light. The shape of Utopia differs from our case.

WARELL (JWr) observed the planet on 3 Nov at LCM=191° W and on 28 Nov at LCM=303° W: Seeing remained poor and Syrtis Mj was just dusky at the evening side on 28 Nov (the temperature then read - 5° C in Uppsala).

In winter, the Japanese districts facing to the Pacific Ocean usually enjoy the fine weather, but the rear side including Fukui suffers from the dismal weather. We had first snowfall on 30 Nov at Fukui. (It also snowed at the beginning of Dec in Kyoto.)

The CMO will be published twice a month from Feb, and hence the observations will be acknowledged if sent fortnightly in January, February and March to arrive by 20th, and 5th of every month.


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