1996/97 Mars Sketch

1996/97 Mars Sketch (6)
from CMO #204 (25 June 1998)

-- Supplement (I) --

The column of Mars Sketch in 1996/97 is in progress, but the already-issued notes seem to have need to be supplemented.

(1) Morning Cloud Detected by HIGA at 107°Ls

Fig 1: Y HIGA's image again on 20 Apr (107°Ls) at ω=210°W
showing a doubled cloud from Elysium

At page 2179 in No.197, Sketch (1) described the butterfly-like white-cloud burst observed by Y HIGA (Hg) on 20 Apr 1997 (107°Ls) at the region covering the morning side of Elysium to its west. However the photo of the surface cited in the page was unfortunately too unclear to show the cloud, and so here we recite it by use of a different copy of the disk as Fig 1. It was made by HIGA from the Video record at ω=210°W on 20 Apr 1997 11:55GMT. We hope the article in No 197 is again revisited if the print appears successful. (In the CMO-Internet, we successfully showed the photo in terms of an colour image in No 197. We show this time another B&W photo originally in Blue.)

(2) Examples of the Equatorial Band Mist

Sketch (2) in No 200 at p2232 dealt with the mist lying along the Equatorial Band (ebm) in which we cited no more than a drawing by HIKI (Hk) made on 20 Feb 1997 (081°Ls) at ω=046°W.

Fig 2: E SIEGEL's EBC on 6 Apr (101°Ls) at ω=101°W
Fig 3: H ISHADOH's observation on 24 May (123°Ls) at ω=275°W

We here supplement two other cases: One is the drawing obtained by SIEGEL (ESg) in Denmark on 6 Apr 1997 (101°Ls) at ω=101°W (Fig 2); being the observation where ESg explicitly caught the EBC for the first time. M Acidalium nearly sat down, but Mareotis L was large and dark to the north of the misted equatorial band. She used Int light and W80A, but also saw the belt through W47. Another example is by ISHADOH (Id) made on 24 May 1997 (123°Ls) at ω=275°W (Fig 3). The mist was rather thicker in the morning side and extended to the afternoon side. The apparent diameter was 9.6 arcsecs and the phase angel was 37°: The latter implies the Elysium area was still just after 1 pm local time though it looks deep afternoon.

(3) Tharsis Observed by HERNANDEZ (CHr)

No 201 at p2243 treated in Sketch (3) the aspect of the Tharsis Ridge and Olympus Mons, but there is found another observation by the present writer (Mn) not yet reported. On the drawing made 20 Mar (093°Ls) at ω=175°W a faint dark spot is found inside a cloud preceding to Olympus Mons quite near the evening limb (Fig 4). This kind of phenomenon should have been pursued continuously, but at that time just made every 40 minutes. Figure 5 reproduces a drawing just received from C HERNANDEZ (CHr) who made the observation on 4 Mar (086°Ls) at ω=156°W: The faint dark markings near the evening terminator look very interesting.

Fig 4: Evening Tharsis on 20 Mar (093°Ls) at ω=178°W by M MINAMI
Fig 5: C HERNANDEZ's drawing in Red on 4 Mar (086°Ls) at ω=156°W

(4) Observations of Olympia

Concerning the npc in 1997, we reviewed its general aspect in No 202 at p2259 in Sketch (4) and mentioned some observations of Olympia, a detachment from the npc. We alluded to the observations by NAKAJIMA (Nj) and Mn on 20 Mar, but unfortunately we missed to report the observation by Id on the very day on 20 Mar 1997 (093°Ls) at ω=185°W (while Mn mainly at ω=183°W) because we stupidly chose a different file to tuck some of his better drawings.

Fig 6: Olympia by ISHADOH on 20 Mar (093°Ls) at ω=185°W
Fig 7: Olympia by S WHITBY on 8 Apr (101°Ls) at ω=161°W by use of a 15 cm speculum

We so cite here the drawing of Olympia of his as Fig 6. The drawing in Fig 4 by Mn was made just before the time, with Olympia not yet just to the south of the npc. Figure 7 reproduces a drawing of Olympia by S WHITBY (SWb) on 8 Apr 1997 (102°Ls) at ω=161°W which shows clearly the detachment to the south-west of the npc. SWb used W21 filter (orange) on a 15cm Newtonian.

We finally again cite a drawing by Id made on 31 May (126°Ls) at ω=206°W in Fig 7. We may say the npc was clearer in May; and thus Olympia was long apparent from March to May around the Martian summer solstice. The HST image cited at p2260 in fig3 well confirms these observations, and these observations provide a proof of a further stationary elongation of the aspect.
Fig 8: Olympia by ISHADOH on 31 May
(126°Ls) at ω=206°W

(5) Hellas by MORITA (Mo)

In No 203 we saw a trend of Hellas in 1997 (Sketch (5) ). In No 204 we added two sets of Hellas images in Red (left) and Green (right) taken by MORITA (Mo) who used a CCD equipped 25cm Newtonian. Not produced however in this CMO-Internet. Hellas is lighter in Green. The first set was made on 16 Apr (105°Ls) at ω=285°W and the second one was on 22 May (122°Ls) at ω=293°W. The second one was taken just one round after from the previous one, but they prove that during the days the apparent diameter much decreased from 13" to 10" and the images turned out to be much poorer.

(Mn : Masatsugu MINAMI)

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