Director: K. Horikawa, Secretary: Y. Iga
Jupiter passed eastern quadrature on Sep. 4, and was in the southern sky of evening. Since it sank below the horizon within a few hours after sunset due to southerly celestial declination, we felt the apparition was shortly over. This month, we received observations listed below.
| Observer | Location | Telescope | Images/Drawings | |
|---|---|---|---|---|
| Carvalho, Fabio | (Brazil) | 25cm Refl. | 3 | images |
| Einaga, Hideo | (Hyogo, Japan) | 30cm Refl. | 17 | images |
| Fukui, Hideto | (Shizuoka, Japan) | 35cm Refl. | 1 | image |
| Go, Christopher | (Philippines) | 28cm SCT | 19 | images |
| Hayashi, Toshio | (Kyoto, Japan) | 35cm SCT | 2 | images |
| Horikawa, Kuniaki | (Yokohama, Japan) | 16cm Refl. | 7 | drawings, 3 images |
| Ikemura, Toshihiko | (Nagoya, Japan) | 31cm Refl. | 9 | images |
| Kanno, Seiichi | (Yamagata, Japan) | 25cm Refl. | 4 | images |
| Mishina, Toshiroh | (Yokohama, Japan) | 20cm Refl. | 7 | images |
| Miyazaki, Isao | (Okinawa, Japan) | 40cm Refl. | 11 | images |
| Narita, Hiroshi | (Kawasaki, Japan) | 20cm Refr. | 5 | drawings |
| Takimoto, Ikuo | (Kagawa, Japan) | 31cm Refl. | 5 | images |
| Yoneyama, Seiichi | (Yokohama, Japan) | 20cm Refl. | 7 | images |
| Yunoki, Kenkichi | (Osaka, Japan) | 26cm Refl. | 36 | images |
Dusky shading emerged in STrZ late August and was suspected of being new STrD. But it retrograded with SEBs dark spots, and disappeared after reaching STrD-1 around Sep. 7. According to investigation of the images before dusky shading formed, thick portion of SEBs was approaching dark spots of the circulating current. Perhaps, the dusky shading was formed by collision between thicker portion of SEBs and the circulating current spot d-k. As a result, spot d-k broke apart into smaller spots, and STB began to broaden preceding it, instead. This was not true STB but STBn which thickened to the north. STrZ was very narrow in this sector. Thick STBn was gradually extending eastward, and the p. end of it was at about II:210 deg. on Sep. 23 (Go). By the way, it seemed that U-turn of dark spots by circulating current lasted this month, because there were many dark spots on SEBs and STrD-1 was conspicuous. But each spot was not able to be tracked because of decrease in observation and unstable seeing.
Activity of SEB Revival was still in progress, but aspect following RS was almost unchanged. On the other hand, SEBs between STrD-1 and RS was gradually darkening, and it had revived around STrD-1 as a dark and firm component which rivals SEBn. Though SEBs was generally quiet in this sector, isolated dark spot was retrograding with +3.8 deg./day. It is known that RS is faded by dark spots of southern branch in SEB Revival, but it was still prominent as orangish oval at II:123.6 deg. (Sep. 20, Ikemura), because all dark spots turned back halfway by the circulating current. The dark spot was at II:94.5 deg. on Sep. 27 (Miyazaki), and it will reach RS early October. It is expected that some changes will be seen.
BA was at II:265.2 deg. (Sep. 19, Einaga). Though it became large to 12-14 deg. temporarily, it tends to contract recently, and according to image by Carvalho on Sep.23, it became a round oval 7.5 deg. long. EZ was notably dusky in the first half of the apparition, but it seemed to be recovering brightness. EZs which had been dark like a belt appeared as light zone generally, though there were many bluish filaments around SED. Also in EZn, conspicuous festoons became fewer. The northern hemisphere was generally dusky and featureless, except for a bright spot in NNTZ. It was at II:285.8 deg., +40 deg. in latitude on Sep. 4 (Yunoki), and was prograding slowly relative to System II. Its brightness at methane band suggests that it has high altitude in Jovian atmosphere like LEBS.
Saturn passed solar conjunction on August 21, and appeared in the east morning sky. In spite of poor condition, observation was already started by an enthusiast.
| Observer | Location | Telescope | Images/Drawings | |
|---|---|---|---|---|
| Einaga, Hideo | (Hyogo, Japan) | 30cm Refl. | 4 | images |
Since tilt of the ring dropped below -10 deg., Einaga's image showed light NTrZ from north of ring A. Tilt of the ring decreases more in this apparition, and will reach -7 deg. at the end of the year. It is expected that the aspect of northern hemisphere, which could never be seen before e.g. NEB etc., can be observed.
(October 11, K. Horikawa)
(Translated on March 27)