6th Report: The CMO/OAA Observations made during the one-month period from

16 March 2003 (153Ls) to 15 April 2003 (169Ls)


Based on the OAA Mars Section article published in CMO #271 (25 April 2003)


Masatsugu MINAMI, Director of the OAA Mars Section


Japanese here


On 16 March, the apparent declination was around 23.5, and read the lowest (from the northern hemisphere), but started to gradually recover. We review here the period from

16 March 2003 at λ=153Ls to 15 April 2003 at λ=169Ls.

The declination attained 22 on 15 April. The central latitude φ moved from 6S to 13S. The apparent angular diameter δ increased from 6.7" to 8.3", while the phase angle ι increased from 39 to 42. The spring time sky in Japan is full of water vapour, and so not preferable for the observation. Overseas observation turned out to increase from the end of April (to be reported in #272), while during the present period just Don PARKER (DPk) came to produce the nicer images.

 

This time we received as follows: In addition to DPk's activity, MORITA (Mo) remains active in Japan. Damian PEACH (DPc) who started earlier at Tenerife, seems to stay in England (we hear he will make an expedition in August to Barbados).

FRASSATI, Mario (MFr) Crescentino, Italia

1 Set of Drawings (25 March 2003) 25020cm SCT

 

ISHADOH, Hiroshi (Id) Naha, Okinawa, Japan

       1 Drawing (22 March 2003)  34031cm speculum

MINAMI, Masatsugu (Mn) Mikuni, Fukui, Japan

38 Drawings (18, 20, 22, 23, 26, 29 March; 6, 10, 13, 15 April 2003)

400, 48020cm ED refractor

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

15 Sets of CCD Images (20, 22, 26, 30 March; 6, 9 April 2003)

f/50x 25cm speculum equipped with an ST-5C

MURAKAMI, Masami (Mk) Yokohama, Kanagawa, Japan

     3 Drawings (22, 25 March; 6 April 2003) 32020cm speculum

NAKAJIMA, Takashi (Nj) Fukui, Fukui, Japan

14 Drawings (20, 20, 29 March 2003)

400, 48020cm ED Goto refractor

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

12 Sets of CCD Images (16, 18+, 25, 29, 30 March; 11, 14 April 2003)

f/60 41cm F/6 Newtonian equipped with an ST-9XE

            +f/3825cm Meulon equipped with a ToUcam

  

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

1 Set of CCD Images (8 April 2003)

18cm spec with a Philips ToUcam Pro

  

VALIMBERTI, Maurice P (MVl) Melbourne, Australia

1 Set of CCD Images (5 April 2003)

f/34 35cm SCT with a Philips ToUcam Pro

 

Fukui City Observatory

 

The Sph and Spc: To observe the last stage of the south polar hood (sph) and the succeeding appearance of the maximal south polar cap (spc), the apparition preceding the so-called great apparition is most appropriate from the view-point of the season and the apparent diameter. In 2001, however, the south polar region was tilted away from the Earth, and hence it was rather impossible to make any definite observation. In this respect, the 1986 apparition was quite favourable. The apparition in 1969 however brought the north-declined φ, and so few data. The 1954 apparition was also suited, and the present writer (Mn) obtained a few data, though we don't use it here.

Mn's dj-vu observations in 1986 at the Taipei City Observatory, Taiwan (located at 25N, by making use of a 25 cm refractor) showed that the sph grew rapidly from λ=145Ls to 150Ls, and at λ=156Ls, the spc popped out, and at λ=160Ls (24 April 1986, δ11.3"), the spc appeared definite. Hellas was observable from the Far Orient around λ=165Ls, and looked slightly whitish. At λ=176Ls, the internal structure of the spc was visible.

 By the way, a look at Mn's observations in the great 1988 apparition shows that the sph/spc was still dull at λ=160Ls, and Mn judged the canopy to be the spc at λ=166Ls on 22 March 1988 while the angular diameter was only =6.4". At λ=168Ls, the upper side of the spc looked depressive. Shotaro MIYAMOTO's observations in 1971 showed the spc was first visible at λ=161Ls (on 11 April 1971, δ=8.7", φ=10S).

The present period just corresponded to the case, and the observations proved that the trend of the sp region was alike the case of 1986. This year, the sph was not conspicuous at λ=135Ls, but from λ=145Ls to 150Ls, the sph grew larger (partly since φ moves southward). We considered the spc was visible from λ=155Ls (20 March 2003, δ6.9"), and at λ=160Ls it became apparent. The apparent diameter was quite smaller than in the 1986 case, and hence no detailed nuance was obtained. The more preferable observations of the sph/spc were made on 22 March 2003 (λ=156Ls) as follows: From Fukui Mn observed at ω=303W, 313W, 322W, 332W, 342W, and 351W, and at the same time NAKAJIMA (Nj) did at ω=308W, 318W, 327W, 337W, 347W. Hellas was whitish misty near the evening terminator, while the perimeter of the spc was apparent dark with Depressiones Hellespontic: MURAKAMI (Mk) observed on the same day that the sp area was bluish white and bounded clearly by a dark perimeter including D Hellespontic. ISHADOH (Id) also made a drawing at ω=338W, and saw the spc bounded by the "dark fringe". Since the season was before the southern spring equinox, the spc was never brilliant. The small diameter prevented from a detailed observations, while Mn saw a brighter core at the evening side of the spc on 29 March (λ=159Ls) at ω=274W, and hence some of the polar clouds were still floating. As April came in, the spc looked definite and stable. Don PARKER (DPk)'s images on 29 March (λ=160Ls) at ω=118W as well as those on 30 March (λ=160Ls) at ω=111W show clearly the spc. MORITA (Mo)'s R images on 20 March (λ=155Ls) at ω=357W and 003W, and on 22 March (λ=156Ls) at ω=335W looks show this. His R images on 30 March (λ=160Ls) also shows it though weakly. In these cases, the RGB composition may be appropriate than the LRGB. Furthermore it is not appropriate in these cases to shorten the R exposure time (just to get a detail) and overexpose the B shoot (just to depict the white hood). Next occasion will visit 15 years later.

Depressiones Hellespontic: The extra darkening of D Hellespontic was pointed out by Don PARKER (DPk) previously on 8 March (λ=149Ls) as reported in CMO #270. DPk also produced finer images on 14 April (λ=168Ls) at ω=302W, 311W and 319W. It looks darker than S Sabus. Strictly speaking, D Hellespontic is not wholly dark, but the darkest part is only along the dark fringe of the spc. Don's image on 14 April at ω=322W shows well the very nuance of the whole area, and also shows that Hellespontus or a dark band lying at Noachis is quite separated from Yaonis Fr which extends upto D Hellespontic. DPk's images on 11 April (λ=167Ls) are also worthy of notice though the seeing poorer. Mo's images on 20 March and 22 March as cited before also show the darkening clearly.

 Olympus Mons: VALIMBERTI (MVl) in Australia showed by a newly employed powerful STC the whitish roll-cloud over Olympus Mons near the terminator on 5 April (λ=164Ls) at ω=166W. Note also that this image marvellously produces, in spite of the mere diameter δ=7.8", a fine (check-shaped) image of Propontis I as shot by the HST. It is however unreasoned why it is also seen through B light.

 M Hadriacum: M Hadriacum is fainter than usual because of a fall-out of dust, and M Tyrrhenum beyond Trinacria is also narrower. This is seen on the images by Mo on 30 March (λ=160Ls) at ω=252W, etc. It is also possible to check visually.

 Ceraunius?: Mn detected a dark band along Ceraunius or its south on 13 April (λ=168Ls), and on 15 April (λ=169Ls). At ω=110W on 13 April, a dark spot was witnessed and so this might have been an old Ascrus Lacus. The R images by DPk on 30 March (λ=160Ls) may show it but not conspicuous. FRASATTI (MFr) detected a bright spot around here on 25 March (λ=158Ls) at ω=072W.

 Chryse: At Fukui we observed a morning (slightly off-white) mist near Chryse on 20 March (λ=155Ls) and on 22 March (λ=156Ls) (especially at ω=001W on 20 March, and ω=332W~352W on 22 March). On the ground (exactly on the rooftop outside the dome), temperature went down to1C (quite different from the case of last year). The mist is also seen on Mo's images on 22 March. DPk's images on 11 April (λ=167Ls) also show (same in G and B).

Miscellaneous: A classical shape of M Acidalium was shot by Mo on 20 March (λ=155Ls) at ω=003W (R image). Thru naked eyes, it looked shortened because of the northern polar hood. Syrtis Mj appeared quite dark and broad in ccd. For example, Mo's on 26 March (λ=158Ls) at ω=295W, and PELLIER (CPl)'s on 8 April (λ=165Ls) at ω=305W. As far as we received, the images by DPk on 14 April (λ=168Ls) at ω=302W looks most detailed. DPk had an occasion to shoot Solis L on 29 March at ω=099W, but the seeing was 4/10. Rather he shot Solis L near the terminator on 30 March (λ=160Ls) at ω=111W. At Fukui, it was observed on 15 April (λ=169Ls) at around ω=083W. In Ddalia, a broadened Phasis hung down. We should however wait until the details come.


The next issue shall treat the period from 16 April (λ=169Ls) to 15 May 2003 (λ=186Ls, δ=10.7"). We hope every observation, if emailed, is sent in a .jpg file to Masami MURAKAMI

cmo@mars.dti.ne.jp

as well as to Masatsugu MINAMI

vzv03210@nifty.com

at the same time. The former is for the CMO Internet, and the latter for the edition of the CMO Report (this column). It is preferable for every file to convey the observer's name or code: If not, it will turn hard to identify later whose file it is in our file list.


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