Monthly Report of the OAA Jupiter-Saturn Section, October, 2004

Director: K. Horikawa, Secretary: Y. Iga

(1) Jupiter

New apparition had started along with October. In spite of low altitude in the east sky and poor condition, we have received many observations listed below. Takimoto is new contributor from this apparition.

ObserverLocationTelescopeImages/Drawings
Ikemura, Toshihiko(Nagoya, Japan)31cm Refl.3images
Einaga, Hideo(Hyogo, Japan)25cm Refl.52images
Kazemoto, Akira(Kyoto, Japan)31cm Refl.4images
Takimoto, Ikuo(Kagawa, Japan)31cm Refl.6images
Fukui, Hideto(Kyoto, Japan)25cm Refl.5images
Horikawa, Kuniaki(Yokohama, Japan)16cm Refl.4drawings
Miyazaki, Isao(Okinawa, Japan)40cm Refl.8images
Yoneyama, Seiichi(Yokohama, Japan)20cm Refl.2images

The first observation of 2004-05 apparition was made by Miyazaki on Oct. 5, being followed ones by Fukui and Horikawa on next Oct. 6. Miyazaki's observation was only 14 days after solar conjunction, and altitude of Jupiter was no more than 7 deg. Because in early autumn, we have clear sky and the ecliptic has large angle to horizon, we can comparatively easily find Jupiter near horizon. But there would be no example of such early observation in recent years.

General aspect of Jupiter almost remained unchanged as that in last apparition. NEB completed broadening all round the planet, and it was seen as broadest belt even exceeding SEB. The belt was generally uniform in darkness without barges and small spots on northern edge, but some images showed it double, indicating that rift activity persisted like as those in last apparition.

RS was at about II:95 deg. with diffuse outline. Though no redness in visual, it was pale orange in images, and Fukui's IR image showed it as clear Hollow. SEB was faint between RS and II:140 deg., indicating that white clouds in this region became relatively active. BA was at II:45 deg. (Oct. 20, Miyazaki), following which dark segment of STB extended to about II:170 deg.

NTB was invisible and quiet all round the planet at present, though the belt had been on the watch for outbreak of North Temperate Current-C during solar conjunction. But it is possible that outbreak will take place at any time, because it had been nearly two years since NTB faded away in late 2002. We should keep watch this apparition too whether bright spot or dark one appears around +25 deg. in latitude. It is known that bright spots of North Temperate Current-C are outstanding in images taken by CH4 absorption band, because these are formed at high altitude in Jovian atmosphere. It is highly recommended taking images by this wavelength.

(2) Saturn

Saturn already passed western quadrature on Oct. 20, and it reached high altitude of southern sky before sunrise. This month, we have received observations listed below.

ObserverLocationTelescopeImages/Drawings
Ikemura, Toshihiko(Nagoya, Japan)31cm Refl.6images
Einaga, Hideo(Hyogo, Japan)25cm Refl.62images
Kazemoto, Akira(Kyoto, Japan)31cm Refl.3images
Suzuki, Takashi(Tokyo, Japan)18cm MCT1image
Takimoto, Ikuo(Kagawa, Japan)31cm Refl.26images
Nakai, Kenji(Hiroshima, Japan)25cm SCT1image
Hatanaka, Akitoshi(Mie, Japan)40cm Refl.3images
Yoneyama, Seiichi(Yokohama, Japan)20cm Refl.3images
Yunoki, Kenkichi(Osaka, Japan)20cm Refl.7images

STrZ white spot discovered last month was not observed this month at all. Image by Einaga on Oct. 17 and ones by Einaga and Takimoto on Oct. 21 showed rather clearly the region around III:300 deg. where the spot detected, but STrZ was uniformly light with no spots in those images. Since it had comparatively high contrast when it observed first, it was expected that the spot would persist for a while. But it might be unexpectedly short-lived.

On the other hand, Grafton's image taken on Oct. 21 showed another white spot in SEBZ at about III:90 deg. This spot had relatively high contrast, clearly seen in his emphasized image, but it was failed to find by domestic observers. It is said that NASA scheduled observation be Cassini spacecraft in a hurry. It would be a glad instance that amateur observations made a contribution to science.

(November 9, K. Horikawa)


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