Director: K. Horikawa, Secretary: Y. Iga
Jupiter was reducing altitude in the southwest sky at evening, as the end of this apparition is drawing near. It was close to Venus from the end of the month to early December, and they were a good target for watching. This month, we received observations listed below.
| Observer | Location | Telescope | Images/Drawings | |
|---|---|---|---|---|
| Akutsu, Tomio | (Philippines) | 35cm SCT | 10 | images |
| Einaga, Hideo | (Hyogo, Japan) | 30cm Refl. | 5 | images, 7 maps |
| Fukui, Hideto | (Shizuoka, Japan) | 35cm SCT | 2 | images |
| Go, Christopher | (Philippines) | 28cm SCT | 14 | images |
| Hayashi, Toshio | (Kyoto, Japan) | 35cm SCT | 4 | images |
| Horikawa, Kuniaki | (Yokohama, Japan) | 16cm Refl. | 4 | drawings |
| Ikemura, Toshihiko | (Nagoya, Japan) | 38cm Refl. | 5 | images |
| Kumamori, Teruaki | (Osaka, Japan) | 20cm Refl. | 3 | images |
| Mishina, Toshiroh | (Yokohama, Japan) | 20cm Refl. | 1 | image |
| Takimoto, Ikuo | (Kagawa, Japan) | 31cm Refl. | 1 | image |
| Yoneyama, Seiichi | (Yokohama, Japan) | 20cm Refl. | 2 | images |
A notable change was observed on SEBs edge, this month. The long dark streak, which extended over 100 deg. preceding RS, disappeared from a sector preceding II:90 deg. Following RS, SEB became narrow by losing bluish component of SEBs edge. It seemed that bluish tint of s. edge became weaker also in other longitude. RS was at II:130.1 deg. (Nov. 13, Kumamori). Though dark arch south of RS and dark streak which shortened to about 30 deg. long preceding RS were still prominent, it is expected that these will fade away.
The interior of SEB was quiet in general, though weak activity of white cloud was seen around II:280 deg., and the post-GRS disturbance kept a halt.
BA reached II:57.2 deg. on Nov. 22 (Einaga), and was observed as an oval with weak redness. STB segment following BA shortened more, and looked like a dark oval with similar size to BA. Large dark oval in STZ was still conspicuous.
EZ gradually became dusky with more bluish festoons than before. NTBn blue segment extended between II:170 and 260 deg., and NNTB was also reviving gradually.
Saturn was prograding in Leo. Increasing the elongation from Sun, it rose high in the southeast sky before sunrise. This month, we received observations listed below.
| Observer | Location | Telescope | Images/Drawings | |
|---|---|---|---|---|
| Akutsu, Tomio | (Philippines) | 35cm SCT | 13 | images |
| Einaga, Hideo | (Hyogo, Japan) | 30cm Refl. | 3 | images |
| Fukui, Hideto | (Shizuoka, Japan) | 35cm SCT | 5 | images |
| Go, Christopher | (Philippines) | 28cm SCT | 1 | image |
| Hayashi, Toshio | (Kyoto, Japan) | 35cm SCT | 1 | image |
| Ikemura, Toshihiko | (Nagoya, Japan) | 38cm Refl. | 21 | images, 2 animations |
| Kumamori, Teruaki | (Osaka, Japan) | 20cm Refl. | 9 | images, 1 animation |
| Nakai, Kenji | (Hiroshima, Japan) | 25cm MCT | 1 | image |
| Takimoto, Ikuo | (Kagawa, Japan) | 31cm Refl. | 2 | images |
| Yoneyama, Seiichi | (Yokohama, Japan) | 20cm Refl. | 12 | images |
The tilt of the ring fell below -2 deg. The ring was narrow like a line, and Cassini's division was not able to see even in high resolution images. Along with ring, the tilt of orbital plane of satellites also reduced, and transits of satellite and its shadow across Saturn came to be observed. Though it is a common event in case of Jupiter, for Saturn, it is rare event which can be observed only around disappearance of ring, once in about 15 years, because Saturn has large inclination against its equator.
On Saturnian surface, SEB and NEB were prominent. Both were double, and SEB was reddish with faint south component, while NEB had different characteristics in which southern part was gray and somewhat faint but northern part was dark greenish. Difference of color was consistent in both hemispheres. It is interesting that it represented difference of circumstances between hemispheres, that is, southern hemisphere has been exposed to the sun for a long period, while northern hemisphere has been behind the ring.
(December 14, K. Horikawa)
(Translated on June 26)