96/97 report 014

1996/97 Mars Observation Reports -- #014 --

OAA MARS SECTION - Monthly Report published in CMO No 192 (25 June 1997)

Martian Surfaces in the Second Half of May and in the First Half of June 1997

- - - by Masatsugu MINAMI, Director of the OAA Mars Section ---

This is the 14th report of the OAA Mars Section of the present apparition: Since the apparent diameter has now much decreased, we shall hereafter publish this column monthly. The present report basically deals with the observations made during the period from 16 May to 15 June 1997. The apparent diameter was 10.2" on 16 May while it decreased to 8.2" on 15 June. The central latitude stayed nearly at 26°N, and still the area of the north polar cap (npc) was well observable. The season proceeded from 119°Ls to 133°Ls, and passed the height of summer of the northern hemisphere.

The planet shines now at meridian when the sun sets, and is only observable for a few hours from 19 o'clock local time here in Japan. On 22 June at 20hGMT, the planet attained the eastern quadrature. We are in a rainy/cloudy season (officially from 8 and 9 June), while the Okinawa district seems to have become free from the rainy days since 20 June, and they welcome and enjoy the sunny summer.

We acknowledge receipt of the following observations this time:
AKUTSU, Tomio (Ak)  Karasuyama, Tochigi, Japan
       6 CCD Images  (18, 27, 30 May)   f/66 32cm speculum, Lynxx PC

GROSS, Horst  (HGr)  Hagen, Deutschland
       2 Drawings  (30, 31 May)     200,250,300×  25cm Schiefspiegler

HIGA, Yasunobu (Hg)   Naha, Japan
       3 CCD Images (prints) (5, 12 May) 25cm spec, Sony DV Camera VX1000 
      21 Video Images  (3, 5, 12, 14, 26, 31 May) 25cm speculum, VX1000

ISHADOH, Hiroshi  (Id)  Naha, Japan
      10 Drawings  (20, 24, 26, 31May; 1 June)  530×  31cm speculum

IWASAKI, Tohru  (Iw)  Kita-Kyushu, Japan
      43 Drawings  (17, 18, 19, 21-27, 30, 31 May; 2, 11, 12, 13 June)
      400×  21cm speculum

MELILLO, Frank J  (FMl)  NY, USA
       6 B&W Photos (12, 17, 21, 22, 24, 27 May) 20cm SC AO-2 TP2415 Wr47 & Wr21 

MINAMI, Masatsugu  (Mn)   Otsu+ / Fukui, Japan
      62 Drawings  (17+, 18, 23, 25, 27, 28, 30, 31 May; 6, 7 12, 13 14 June)
      400× 20cm speculum+ / 400,480× 20cm refractor*

MURAKAMI, Masami  (Mk) Fujisawa, Japan
       8 Drawings  (18, 25#, 30 May; 14 June) 370×  15cm speculum/ 400×  20cm refractor#

NAKAJIMA, Takashi (Nj)  Fukui, Japan
      17 Drawings  (18, 25 May; 7, 13, 14 June)    400, 480×  20cm refractor*

NARITA, Hiroshi  (Nr)  Kawasaki, Japan
      36 Drawings  (16, 18, 21, 25, 26, 28, 30 May; 1, 5, 7 June)  400×  20cm refractor#

NIKOLAI, Andre  (ANk)  Berlin, Deutschland
       4 Drawings (18@, 28 May; 5, 10 June) 
       250×  11cm refr@ /375×  15cm refraktor at the WFS      

OHBA, Yoshio (Oh) Yamagata, Japan
       1 Drawing  (28 May)  320×  20cm speculum

SIEGEL, Elisabeth (ESg)  Malling, Danmark
       2 Drawings  (18, 24 May)  270×  20cm Schmidt-Cassegrain

TEICHERT, Gerard (GTc) Hattstatt, France
       9 Drawings  (12, 18, 25-28, 30, 31 May; 4 June) 280,310,330,350,390×  28cm SC

WARELL, Johan  (JWr)  Uppsala Univ, Sweden
       5 Drawings  (19 Apr; 8, 11, 15, 16 May)  330,400×  16cm refractor

                                              * Fukui City Observatory
                                              # Tama AstroObservatory
As the observations obtained earlier, we received with thanks the following:
DIJON, Jean  (JDj)  Champagnier, France
         3CCD Images (beginning of May) 31cm spec with KAF400   FITS file

FALSARELLA, Nelson  (NFl) Brasil
        12 Drawings  (6, 8-12, 14, 17, 20, 23, 29 Apr; 5 May) 260×  20cm speculum

GRAHAM, David L (DGh)  North Yorkshire, UK
         3 Drawings  (20, 21 Apr)   285×  15cm refractor

HEATH, Alan W  (AHt)  Nottingham, UK
       13 Drawings  (1, (11, 12), 15, 19. 21, 24, 26, 28, 30 Mar; 15, 23, 30 Apr; (1, 14 May)) 
       190,320×  30cm speculum, 320,200×  20cm Schmidt-Cassegrain

ISHIBASHI, Tsutomu  (Is)  Sagamihara, Kanagawa, Japan
        5 Colour Photos  (4 Mar; 1, 10 Apr)  31cm speculum    Fujichrome  Provia 400 

From Japan
the region where Syrtis Mj was near the CM eastward through the region where S Meridiani was seen in the afternoon faced toward us this period. The weather here was however poor within the rainy/cloudy season.

The bright part of the north polar cap (npc) was definite, and NAKAJIMA (Nj) and the present writer (Mn) considered that the npc looked stable on 13 June (132°Ls) when the contour of the npc was very evident by the presence of Hyperboreus L. At the end of May when Utopia was facing to us the contour of the npc looked blurred because the surrounding was faded. ISHADOH (Id) noted that the limb of the npc could not well be fixed on 20 May at ω=334°W.

Olympia was definitely watched by Id also this time: Olympia was observed by Mn on 18 May at ω=292°W to the east of the npc while Id detected it clearly to the south of the npc on 31 May (126°Ls) at ω= 206°W. It was also revealed by Id on 1 June at ω=177°W.

Elysium was also widely observed this period. Mn saw Elysium Mons on 23 May (123°Ls) at ω=269°W. To Id, Elysium was usual on 24 May at ω= 265°W while light at ω=275°W. Elysium was then located near the preceding limb, but its local time was just after 1:00pm. At the next ω= 284°W, the preceding limb was just light and no description of Elysium. The morning Elysium was observed by MURAKAMI (Mk) on 25 May at ω=228°W when it showed rather an orange tint and its northern part was a bit whitish. On 27 May at ω=222°W et al, Mn observed that Elysium and Cebrenia were light and the dark patch at Aetheria looked greenish. On 28 May at ω= 190°W and 200°W et al the northern part of Elysium was whitish misted, and at ω=229°W Elysium Mons was watched . OHBA (Oh) caught Elysium was a bit light at ω=222°W on the same day. According to Id's observation on 31 May at ω=206°W, Elysium was out of the morning mist but usually light. This morning mist was detected at the same time also by Mn. On the same day (31 May) at ω=218°W, Id considered that Elysium was not particularly light while the Video colour images by HIGA (Hg) at ω= 213°W, ω=223°W and ω=234°W show the classical Elysium to be light evident. IWASAKI (Iw) watched regularly Elysium for example on 25 May, 26 May, 27 May at ω=241°W, but noted that it was usually like a desert while Cerberus-Styx was dark evident.

Propontis I was observed from 27 May from Japan: Typically it was caught by Id on 31 May at ω=206°W, and Cerberus-Styx was dark as well as the patch at Aetheria. Mn observed similarly at the same time, as mentioned, and Iw observed at ω=203°W describing a similar configuration. Id noted that the markings became fainter at ω=218°W while Mn noted that the Aetheria dark patch was just fainter than Gyndes and Styx at ω=216°W. Formally Mn noticed that the area of Cerberus-Styx and Propondices looked very dark on 28 May at ω=210°W as if some dark marking like M Acidalium lay there (same from ω=190°W to ω=239°W). On 30 May AKUTSU (Ak) took a series of CCD at ω=185°W, and the R image shows the dark Propontis I and II. On the drawing by Id on 1 June at ω=177°W, Propondices described the darkest. .

It is now hard to observe the morning and evening Tharsis. The very evening Tharsis is not observable because of the phase angle. The Olympus Mons rotar cloud was bright from ω=200°W on 28 May near the preceding limb, and became very bright at ω=210°W on the limb, but it was about 2:30pm local time since the phase angle=38°. It became very blurred light at ω=239°W. The afternoon Tharsis was watched as well as Xanthe at Fukui on 6 June (129°Ls) at ω=158°W et al, but any positive statement about details was difficult to make. Ascraeus L-Mareotis L was dark evident even in the afternoon. (The cloudy weather from the end of May to the beginning of June prevented us from further observations.) The morning Tharsis was caught as a large white patch on 7 June at ω=095°W/ 105°W (by Mn), but the detail was not also caught due to the smaller disk diameter and the less brightness of the morning area.

5 bis )
This was not obtained in this period, but just received Hg's Video tape on 5 May (114°Ls) includes very interesting shots: As mentioned, the HST images taken on 30 March (097°Ls) show us the precise configuration of the morning volcanoes (Cf #191 p2102) to lead us to identifing our observations of unknown dark spots, and the comparison reveals us to find at least the crater of Ascraeus Mons and the shadowy region around Arsia Mons in the Hg's moving images taken on 5 May at ω=072°W, ω=082°W, ω= 092°W and ω=101°W. Furthermore the processed B image (printed-out) at ω=089°W on the same day clearly shows the three dark spots of Ascraeus, Pavonis and Arsia Montes as well as the white dark patch which flowed out westward from the area between Ascraeus Mons and Pavonis Mons. These in turn tell us how to identify the dark and white markings obtained by us in March: For instance Id observed the craters of Ascraeus Mons and the shadowy area around Arsia Mons 27 Mar at ω=072°W and on 30 Mar at ω=069°W. Mn also noted "A dark spot is visible on the morning side near the limb; to be checked later" on 27 Mar at ω=054°W, which might have been the crater of Ascraeus Mons.

ISHADOH (Id) became to pay much attention to any thin mist, advised by the Director, and on 24 May (123°Ls) at ω=275°W Id observed a belt of white mist along the equatorial band from the morning terminator to the evening (one may say it 's an EBC). Because of the phase angle, the afternoon side is lighter. Syrtis Mj was still beneath under the mist, but slightly recovered compared with the case of ω=265°W. Id succeedingly observed that on 26 May at ω=253°W, the southern part of Syrtis Mj was thickly misted and the northern part looked faint in a blue-greenish tint. At ω=263°W, again something like the EBC. AKUTSU (Ak)'s B-light CCD images on 18 May (120°Ls) at ω=294°W and ω=304°W show the weaker Syrtis Mj with the mist on both sides.

Hellas was observed by Iw to be very whitish bright on 17 May (119°Ls) at ω=306°W and 316°W, but slightly toned down on 18 May and 19 May at ω=297°W. Mn observed that on 18 May at ω=284°W, Hellas was rather dull but definitely light at ω=294°W. At ω=302°W the inside of the area showed a not-uniform detail. Mk noted that Hellas was as bright as the npc on 18 May at ω=297°W. On 24 May Id described that Hellas was duller on 24 May at ω=274°W, but recovered at ω=284°W. On 24 May the phase angle was 37°.

We consider that Utopia has become much weaker than before. On 18 May at ω=292°W or on 23 May at ω=240°W etc, Utopia appeared rather brownish to Mn.

On 7 June, Solis L and Tithonius L were observed dark from Fukui, but when they were on the morning area it was difficult to discern. Tempe became lighter when M Acidalium lay near the preceding limb, and Alba was also seen inside the disk on ω=144°W. Nilokeras was dark, and the dark band including the large Ascraeus L went up to the area of Arsia Mons. On 12 June we considerd no disturbance was there at Chryse to Niliacus L.

Argyre was seen a bit light on 12 June. Different to this, the southern limb appeared light largely after ω=100°W. On 7 June, Nj and Mn observed the southern limb largely light from ω=130°W to ω=150°W.

Overseas Observations

From America:

MELILLO (FMl) still tried to take pictures of the equatorial band cloud (EBC) which however is said to be evident only on the Wr47 image on 12 May at ω=221°W where Elysium Mons is not clear, while the Wr21 image shows well the classical Elysium. FMl also took on 17 May at ω=195°W, 21 May at ω=160°W. Those on 22 May & 24 May at ω=130°W, and on 27 May at ω=072°W seem to show a rough cloud patch near Tharsis.

From Europe:

GROSS (HGr) made drawings on 30 May (125°Ls) at ω=306°W, and 31 May at ω=279°W. Both drawings state that Hellas was as light as the npc (Intensity 1). He detected N Alcyonius when the disk diameter=9.2".

NIKOLAI (ANk) observed a haze over the afternoon Noachis in addition to the evening and the morning mist on 18 May at ω=055°W when M Acidalium was dark near the CM. On 28 May at ω=348°W ANk intensity-estimated Hellas near the preceding limb to be 2 through blue (B+W081). Through orange light (B+W21), Syrtis Mj was still dark and S Sabaeus was seen well. On 5 June at ω=269°W, Syrtis Mj was visible in the morning through orange, and Hellas also seen. On 10 June at ω=224°W, Elysium was not seen through B +W21.

SIEGEL (ESg) saw the afternoon mist as well as the morning mist at ω= 095°W on 18 May through Int and Wr80a. This may be identified with the so -called EBC, but not so evident through Wr47. On 24 May at ω=021°W, M Acidalium was observed to split up into two by a narrow band approximately the same colour as the surrounding deserts. (Elisabeth however didn't seem to detect Hyperboreus L adjacent to the npc. Misted?) Morning mist at Xanthe was noted.

TEICHERT (GTc) observed the planet on 12 May at ω=128°W, 18 May at ω= 071°W, 25 May at ω=011°W, 26 May at ω=001°W, 27 May at ω= 353°W (where Ismenius L was evident), 28 May at ω=346°W, 30 May at ω=324°W, 31 May at ω=313°W, and 4 June at ω=275°W.

WARELL (JWr)'s drawing on 16 May (119°Ls) at ω=137°W shows that a southern limb area was quite light (which he identify as Phaethontis). He formerly observed on 19 Apr at ω=005°W (where the morning Chryse was light and extended to the preceding limb by use of Wr38A. Tempe was also light), on 8 May at ω=167°W (where the area of Propondices was largely dark), on 11 May at ω=149°W and on 15 May at ω=112°W (where Nilokeras was dark and Ascraeus L was detected).

We- Further- Received :

Dijon (JDj)'s FITS file, which was precedently received, was read by Ns by means of the Hidden Image, and we found three new images however without data file: They were taken by 6 May: The first one shows Syrtis Mj in the evening and M Acidalium at the morning side. A part of the npc bright. The second Syrtis Mj in the morning and Elysium as well as Cebrenia light. N Alcyonius and the dark patch at Aetheria are definite. In the last image Elysium is near the noon and N Alcyonius and Casius are inside. The last two show the dull white Eridania.

GRAHAM (DGh) observed Mars on 20 Apr (108°Ls) at ω=323°W and ω= 354°W; in the latter Syrtis Mj was slim while M Acidalium on the opposite side was darker together with Hyperboreus L. On 21 Apr at ω=346°W, DGh detected a light patch at Cydonia.

HEATH (AHt) obtained a total of 18 drawings this apparition, a part of which were reported in #187 (and we also count the blue drawings differently). These were Alan's observations of Mars made at his former place (and by the use of the PHILLIPS telescope) for the last time. We hear that his observations this opposition have been hampered by a local tree which obstructed the view before midnight.
The first observation was made on 1 Mar at ω=114°W, where the npc was large and roundish. Solis L was visible in the evening.
The observations on 11 and 12 Mar were reported in #187.
On 15 Mar (091°Ls) at ω=340°W, Syrtis Mj was slim near the evening terminator, and M Acidalium on the morning side. Chryse light near the morning limb (as bright as the npc through Wr47).
On 19 Mar (093°Ls) at ω=287°W, Hellas was bright and was equal in brightness to the npc with Wr44a and Wr47. Syrtis Mj was estimated at intensity 7 through Int, but by use of Wr44a it went down to 2 (while M Tyrrehnum remained 4). Alan commented that Syrtis Mj was very visible by 150~6.5cm FOX refractor. Note that his observation of the brightened Hellas was made in the early stage (cf p2070 #189). He also made a Wr47 drawing on 21 Mar (094°Ls) at ω= 289°W where Hellas was bright and Syrtis Mj was invisible (while M Tyrrhenum 5).
On 24 Mar at ω=258°W, Hellas was at intensity 0 through Wr47. These observations by AHt through blue light are coincident with the result shown by a B light image produced by the HST on 30 Mar (the B light image processed by Mk; a thin EBC presents while Syrtis Mj invisible).
Drawings then made on 26 Mar at ω=211°W and 28 Mar at ω=228°W.
On 30 Mar at ω=191°W, Propontis I was detected; Elysium was light in a light but not bright belt shape. On 31 Mar made at ω=190°W.
On 9 Apr (102°Ls) at ω=079°W, Xanthe showed a rosy colour, and M Acidalium at 6. There was a large shadowy patch near Ascraeus L.
On 11 Apr at ω= 068°W the same dark marking was detected similarly. Xanthe was twice the size of the npc and bright through Wr47.
On 15 Apr, he used an SCT (Celestar-8) and made drawings at ω=014°W and ω=028°W: S Meridiani was definite at 6, M Acidalium also at 6 and Hyperboreus L was checked. He compared the image of the new 20cm SC with the more familiar image by the famous 30cm spec: The 30cm gave him a slightly better contrast and the telescope was much more stable. Used similar magnification at 320× .
On 23 Apr at ω=316°W, Hellas was bright and white.
The final drawing received was made on 30 Apr at ω=248°W, while the observing notes on 1 May at ω=250°W and on 14 May at ω=037°W are also included: The defect of illumination was strong and the preceding limb side was lighter (obtained by Celestar-8). The one on 14 May would be Alan's last observation of this apparition which was obtained when the disk diameter=10.5.

FALSARELLA (NFl) seemed to detect Olympus Mons on 6 Apr (101°Ls) at about ω=135°W where he also described a dark band between it and the Tharsis rotar cloud, and saw Propontis I at the morning side. NFl seemed to see an EBC on 8 and 9 Apr at about ω=100°W through blue. In mid-Apr Hyperboreus L was seen just as a dark fringe of the npc. On 29 Apr (111°Ls) at ω=300°W, Hellas was at intensity 0. On 5 May (114°Ls) at ω=240°W, there was a light triangular area near Elysium through blue.

ISHIBASHI (Is)'s colour photo on 3 Mar (086°Ls) at ω=345°W was taken 40 minutes after the one reported in #188 p2055, and shows as well the Chryse mist thickly at the morning limb which extends to Tempe. It may be said that the mist also extends to Aeria near the evening terminator. Noachis looks also hazy. The photos on 1 Apr (098°Ls) at ω=023°W/ 031°W show the whitish Chryse-Xanthe. Deucalionis R is a bit hazy in the afternoon. The photos on 10 Apr (102°Ls) at ω=308°W/315°W show

Reports will be acknowledged if air-mailed to M MINAMI at Mikuni
(ask the mail-address through vzv03210@niftyserve.or.jp ) .

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