19

th Report:

The CMO/OAA Observations made during a fortnight period

 from

16 November 2003 (299°Ls)

to

30 November 2003 (308°Ls)

 


An OAA Mars Section article to be published in CMO #284 (10 December 2003 issue)


 Masatsugu MINAMI, Director of the OAA Mars Section


Japanese version here


T

he present report deals with the CMO observation of Mars made during the fortnight period from 16 Nov 2003(λ=299°Ls) to 30 Nov 2003(λ=308°Ls). This Martian season makes recall us the great dust storm in 1973 which started at λ=300°Ls, and we know the size of the spc begins to fall into the smallest remnant size. The central latitude φ was 25°S to 26°S, so that the southern hemisphere faced to us maximally. The apparent diameter δ went down from 12.8" to 11.2". The phase angle ι was 41° to 42°, while it was near the maximal since defect of illumination was predicted to proceed no more than ι=42.3" in mid-December.

 

T

he observers who contributed this time were as follows:

    

 

AKUTSU, Tomio (Ak) Karasuyama, Tochigi, Japan

            8 Sets of CCD Images (+1 IR image)

(18, 19, 23, 26 November 2003)

                              f/33×32cm spec with a Bitran BJ-41L

     

BENAVIDES, Rafael (RBn)   Córdova, España

            2 CCD Images (19, 25 November 2003)  24cm SCT with a ToUcam

    

IWASAKI, Tohru (Iw)  KitaKyushu, Fukuoka, Japan

       16 Drawings (16, 17, 23, ~25 November 2003)  400×21cm speculum

    

FRASSATI, Mario (MFr)  Crescentino (VC), Italia

            1 Drawing (17 November 2003)    250×20cm SCT

    

KARRER, Michael (MKr) St Radegund, Österreich

            1 CCD Image (20 November 2003)

                       f/35×18cm Meade Refraktor with a ToUcam

     

KUMAMORI, Teruaki (Km)  Sakai, Osaka, Japan 

            6 CCD Images (18#, 21, 23, 26# November 2003)

              f/84×20cm Dall-Kirkham & f/40×60cm Cass# with a ToUcam

                                                # Sakai City Observatory

    

MELILLO, Frank J (FMl)  Holtsville, NY, USA

           4 Red CCD Images (16, 22, 26 November 2003) 

                            20cm SCT with a Starlight Xpress MX5

    

MINAMI, Masatsugu (Mn)  Fukui, Fukui, Japan

           31 Drawings (17, 18, 23, 26November 2003)

                        480, 400, 340×20cm F/12 ED Goto refractor*

                           *Fukui City Observatory, Fukui

    

MORITA, Yukio (Mo)  Hatsuka-ichi, Hiroshima, Japan

           15 Sets of  CCD Images (+1 B +2 R Images)

(16, ~18, 21, ~24, 30 November 2003)

                                f/50×25cm spec equipped with an ST-5C

    

MURAKAMI, Masami (Mk)  Yokohama, Kanagawa, Japan

      11 Drawings (16, 17, 21, 26 November 2003) 

320, 400×20cm speculum

    

NAKAJIMA, Takashi (Nj)  Fukui, Fukui, Japan

            4 Drawings (17 November 2003)  

480, 400×20cm F/12 ED Goto refractor*

                                                *Fukui City Observatory, Fukui

    

NARITA, Hiroshi (Nr)  Kawasaki, Kanagawa, Japan

            4 Drawings (21, 26 November 2003)  400×20cm refractor

    

PARKER, Donald C (DPk)  Miami, FL, USA

            8 Sets of CCD Images (+2 R Images) 

(18, 22, 25 November 2003)

                     f/55, 59×41cm F/6 spec equipped with an ST-9XE

    

PEACH, Damian A (DPc)  Loudwater, Buckinghamshire, UK

            1 Sets of CCD Images (26 November 2003) 

                               f/31×28cm SCT with a ToUcam

  

PELLIER, Christophe (CPl)  Bruz, Ille-et-Vilaine, France

            1 Sets of CCD Images (+ 1 B Image)(16 November 2003)

                        18cm spec with a modified B&W ToUcam Pro

    

ROEL SCHREURS, Eric (ERl)  Mexico

            1 CCD Image (22 November 2003)

 f/50×25cm TEC Mak/MX70 with a ToUcam

    

SIEGEL, Elisabeth (ESg)  Malling, Danmark

            4 Drawings (17, 19, 24, 28 November 2003) 270×20cm F/10 SCT

    

TATUM, Randy (RTm)  Richmond, VA, USA

            1 CCD Image (22 November 2003)  f/12×25 cm spec with a ToUcam

    

TEICHERT, Gérard (GTc)  Hattstatt, France

            4 Drawings (18, 20, 21, 26 November 2003) 330×28cm SCT

  

VALIMBERTI, Maurice P (MVl)  Melbourne, Australia

            2 CCD Images (24, 26 November 2003)

f/41×35cm SCT with a ToUcam Pro

  

Van Der VELDEN, Erwin (EVl)  Brisbane, Australia

            4 CCD Images (19, 20, 23, 29 November 2003)

                           f/31×20cm SCT with a Vesta Pro modified

    

WARELL, Johan (JWr)  Tcuson, AZ, USA

       6 Sets of CCD Images (16, 18, 19, 21, 27 November 2003) 

                                  f/24×25cm SCT with a ToUcam

 

M

orning Mist near Solis L: At the beginning of the period, we could watch the area of Solis L at the morning side from Japan covered by the morning mist which attracted us. On 17 Nov (λ=300°Ls), we (Mn & Nj) at Fukui started from 7:10GMT (ω=046°W) before Sundown and gradually saw the mist as the dusk gathered. The angles were caught by ccd a few days later. On the day, MORITA (Mo) took B images at ω=116°W (11:46GMT), and 127°W, and described the white cloud over Amazonis. On 18 Nov (λ=301°Ls), KUMAMORI (Km) produced the image at ω=061°W,  AKUTSU (Ak) at ω=078°W, 088°W, 103°W, and Mo at ω=100°W, 105°W. Note the interesting Tharsis cloud on Ak’s images. On 19 Nov (λ=301°Ls), Van der Velden (EVl) took at ω=054°W, Ak at ω=062°W, 074°W (B). On 20 Nov (λ=302°Ls), EVl made at ω=048°W, and on 21 Nov (λ=303°Ls), Km at ω=072°W, and Mo at ω=074°W. Mo further continued and took on 22 Nov (λ=303°Ls) at ω=072°W, and on 23 Nov (λ=304°Ls) at ω=069°W. The morning mist to the WS of Solis L was conspicuous. Here we collected the B images to compare near ω=070°W.

 

Whitish Bright Spots observed by SIEGEL: Elisabeth SIEGEL (ESg), visual observer in Denmark, detected a bright spot on 19 Nov (λ=301°Ls) at ω=183°W and another on 28 Nov (λ=306°Ls) at ω=075°W by the use of Wr47 (blue-violet). The spot on 19 Nov was observed near or on the morning Elysium Mons with a size just smaller than the spc but larger to be said ‘star like”. The colour is whitish and same through Wr47 with the spc. See ESg’s LtE for a further literal expression. She chased this for more tan half an hour until ω=194°W. The spot found on 28 Nov was at around Ascræus Mons which stood out inside the morning mist or fog. The size was slightly larger than the one on 19 Nov and as large as the spc and its shape was roundish. It was bright through Wr47, but also visible with other filters like Wr58. She chased this until ω=082°W.

 It can be roughly said that Elysium Mons was located at the morning side within one hour after the Sunrise at the ESg time on 18 Nov, and Ascræus Mons on 28 Nov was a bit more than one hour after the Sunrise. So it is quite possible they were the reflection of the Sun beam scattered from the cloud made of coarse ice grains. Since the phase angle ι was about 40° at that time, the reflector must have been at the preceding (maybe steep) flank of the mountain. It will not so difficult to calculate the angle of the slope where the cloud was stuck.

We received this information on 2 December and it was announced readily in Director's Note of the Façade. However we felt that it must have been alerted earlier in Europe. The present writer (Mn) observed the angles ω=075°W, 085°W on 17 Nov and 18 Nov ( as well as at ω=066°W on 23 Nov), while he did not notice the brightening at Tharsis. As noted above, Ak took images on 18 Nov (λ=301°Ls) at ω=078°W, 088°W, and these B images may be suggestive. We hitherto paid much attention to the evening cloud associated with Montes and have a lot of data, but very few about the morning side. We should so plan to give the high frequent observations about the morning clouds and mists after opposition.

 

The NPH: The tilt φ of the north pole is very away from the Earth, while the nph looked obvious and so the nph must have been very active. The image by EVl on 19 Nov (λ=301°Ls) at ω=054°W shows the thick nph over M Acidalium. Ak’s B image on the day at ω=062°W also well shows this phenomenon. It is also conspicuous on the image on 20 Nov (λ=302°Ls) by EVl at ω=048°W. On the opposite side, PARKER (DPk)’s images on 22 Nov (λ=303°Ls) at ω=250°W~261°W show that the nph extended to half of the Ætheria dark patch. DPk’s another set of images on 25 Nov (λ=305°Ls) at ω=220°W, 232°W also show this. The mist which flows over to Chryse from the nph is well shown on the images by Mo on 24 Nov (λ=305°Ls) at ω=013°W, 019°W.

 

The SPC: The angular diameter much decreased to the effect that it is difficult to see the details of the spc, but several excellent images made by DPk around 18 Nov (λ=301°Ls) seem to show some diffusions outside the perimeter of the remnant spc. The spc shown on the images by VALIMBERTI (MVl) on 24 Nov (λ=304°Ls) at ω=021°W, as well as on 26 Nov (λ=305°Ls) at ω=357°W looks to show a deformation of the spc if not any ghost. The Viking image of the spc at λ=297°Ls still showed a diffused something from the residual spc towards Ω=000°W. The MGS images don’t prove explicitly, but some show still obscure diffusion around the clear perimeter of the remnant.

 

Wine Coloured Ground: As frequently noted in this series of the reports, the dark markings on the southern hemisphere have shown a tint of wine colour as the airborne dust began to settle. This period, as a representative, we pick out DPk’s images on 22 Nov (λ=302°Ls) at ω=250°W, 253°W, 256°W. These prove the typical colouring of M Chronium and Tiphys Fr. Hitherto the ToUcam colour images have shown these phenomenon, while ROEL (ERl)’s image at ω=217°W, and TATUM (RTm)’s at ω=232°W on the same day failed to produce the difference of colour. Similarly the hemisphere where Solis L prevails was expected to show the colour difference, but PEACH (DPc)’s LRGB image on 26 Nov (λ=305°Ls) at ω=126°W just shows the markings to be dark monochromatic due to the L ingredient.

 

Details of Ausonia-Hellas shown by Don PARKER: DPk’s images on 18 Nov (λ=301°Ls) at ω=287°W, 293°W, and 297°W provide, in addition to the another example of the wine coloured area, some details around Trinacria, Ausonia and the eastern part of Hellas though the angular diameter was down to δ=12.8". If compared with the images of the same angle made two months before (here with DPk’s image on 8 Sept (λ=257°Ls) at ω=287°W), the inside of Hellas looks to show more shadowy details (like Zea L), and the boundary area of Hellas and Trinacria also show up a bit more contrast. Note however that if compared with the images of DIJON (JDj) on 3 September and of GRAFTON (EGf) on 14 September (treated in Report #14 in CMO #279), the difference is not so definite. Here there is a difference of phase angle ι by 30° between 18 Nov and 8 Sept implying the difference of the local time (MLT) by 2 hours, and so we also compare the morning sides with similar MLT. Yaonis Fr might have been clearer.

 

WARELL’s Observations of the Evening Hellas: It is interesting to see the series of images of WARELL (JWr) made on 16 Nov (λ=299°Ls) at ω=027°W, on 18 Nov (λ=301°Ls) at ω=351°W, on 19 Nov (λ=302°Ls) at ω=334°W, 357°W, and on 21 Nov (λ=302°Ls) at ω=322°W: these show a variation of Hellas in the afternoon. The image size is small, but the colour looks pretty. Especially the 16 Nov image is a gem rich in colour. JWr was productive this period: The B image on 21 Nov is interesting but shows dark markings to much.

 

FRASSATI’s Observation of Protrusion on 17 November: A protrusion from the terminator similar to the one observed at the Asian side in the first half of November was observed at the European side by FRASSATI (MFr) on 17 Nov (λ=300°Ls) at ω=201°W. Since it was checked at the same angle, both phenomena must have been of the same nature. However we miss the reports before and after as well as the observations by European observers. MFr’s drawing shows a bright white cloud preceding the irregularity, while this gives a different impression compared with our case made a fortnight before.

 


T

he next issue shall treat the observations made in the First half of December 2003 from 1 December (λ=308°Ls, δ=11.1") to 1 December 2003 (λ=316°Ls, δ=9.7").


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