6th Report: The CMO/OAA Observations made during the one-month period from
16 March 2003 (153°Ls) to 15 April 2003 (169°Ls)
Based on the OAA Mars Section article published in CMO #271 (25 April 2003)
Masatsugu MINAMI, Director of the OAA Mars Section
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=153°Ls to 15 April 2003 at λ=169°Ls.
attained －22° on 15 April. The central latitude φ
moved from 6°S to 13°S. 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
This time we received
as follows: In addition to DPk's activity, MORITA
(Mo) remains active in
FRASSATI, Mario (MFr) Crescentino, Italia
1 Set of Drawings (25 March 2003) 250×20cm SCT
1 Drawing (22 March 2003) 340×31cm speculum
38 Drawings (18, 20, 22, 23, 26, 29 March; 6, 10, 13, 15 April 2003)
400, 480×20cm ED refractor＊
MORITA, Yukio (Mo) Hatsuka-ichi,
15 Sets of CCD Images (20, 22, 26, 30 March; 6, 9 April 2003)
f/50×x 25cm speculum equipped with an ST-5C
3 Drawings (22, 25 March; 6 April 2003) 320×20cm speculum
14 Drawings (20, 20, 29 March 2003)
400, 480×20cm ED Goto refractor＊
PARKER, Donald C (DPk)
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/38×25cm Meulon equipped with a ToUcam
PELLIER, Christophe (CPl) Bruz,
1 Set of CCD Images (8 April 2003)
18cm spec with a Philips ToUcam Pro
VALIMBERTI, Maurice P
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 déjà-vu observations in 1986 at
the Taipei City Observatory, Taiwan (located at 25°N, by making use of a 25 cm
refractor) showed that the sph grew rapidly from
λ=145°Ls to 150°Ls, and at λ=156°Ls, the spc
popped out, and at λ=160°Ls (24 April 1986, δ＝11.3"), the spc appeared definite.
By the way, a look at Mn's observations in the great 1988 apparition shows that the sph/spc was still dull at λ=160°Ls, and Mn judged the canopy to be the spc at λ=166°Ls on 22 March 1988 while the angular diameter was only =6.4". At λ=168°Ls, the upper side of the spc looked depressive. Shotaro MIYAMOTO's observations in 1971 showed the spc was first visible at λ=161°Ls (on 11 April 1971, δ=8.7", φ=10°S).
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=135°Ls, but from λ=145°Ls to 150°Ls, the sph
grew larger (partly since φ moves southward). We considered the spc was visible from λ=155°Ls (20 March 2003, δ＝6.9"), and at
λ=160°Ls 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=156°Ls) as follows: From Fukui Mn observed at
ω=303°W, 313°W, 322°W, 332°W, 342°W, and 351°W, and at the same time
NAKAJIMA (Nj) did at ω=308°W, 318°W, 327°W, 337°W, 347°W.
Depressiones Hellesponticæ: The extra darkening
of D Hellesponticæ was pointed out by Don PARKER (DPk) previously on 8 March (λ=149°Ls) as reported in CMO #270.
DPk also produced finer images on 14 April (λ=168°Ls) at ω=302°W, 311°W
and 319°W. It
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=160°Ls) at ω=252°W, etc. It is also possible to check visually.
Ceraunius?: Mn detected a dark band along Ceraunius or its south on 13 April (λ=168°Ls), and on 15 April (λ=169°Ls). At ω=110°W on 13 April, a dark spot was witnessed and so this might have been an old Ascræus Lacus. The R images by DPk on 30 March (λ=160°Ls) may show it but not conspicuous. FRASATTI (MFr) detected a bright spot around here on 25 March (λ=158°Ls) at ω=072°W.
Miscellaneous: A classical shape of
M Acidalium was shot by Mo on 20 March (λ=155°Ls) at ω=003°W (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=158°Ls) at ω=295°W, and
PELLIER (CPl)'s on 8 April (λ=165°Ls) at ω=305°W. As far
as we received, the images by DPk on 14 April (λ=168°Ls) at ω=302°W looks
most detailed. DPk had an occasion to shoot Solis L
on 29 March at ω=099°W, but the seeing was
4/10. Rather he shot Solis L near the terminator on 30 March (λ=160°Ls) at ω=111°W. At
The next issue shall treat the period from 16 April (λ=169°Ls) to 15 May 2003 (λ=186°Ls, δ=10.7"). We hope every observation, if emailed, is sent in a .jpg file to Masami MURAKAMI
as well as to Masatsugu MINAMI
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.