| Observer | Location | Telescope | Images/Drawings | |
|---|---|---|---|---|
| Akutsu, Hiroaki | (Hokkaido, Japan) | 28cm Refl. | 2 | images |
| Einaga, Hideo | (Hyogo, Japan) | 25cm Refl. | 17 | images, 2 maps |
| Fukui, Hideto | (Shizuoka, Japan) | 25cm Refl. | 11 | images |
| Hayashi, Toshio | (Kyoto, Japan) | 35cm SCT | 3 | images |
| Horikawa, Kuniaki | (Yokohama, Japan) | 16cm Refl. | 4 | drawings |
| Mishina, Toshiroh | (Yokohama, Japan) | 20cm Refl. | 1 | image |
| Miyazaki, Isao | (Okinawa, Japan) | 40cm Refl. | 38 | images |
| Takimoto, Ikuo | (Kagawa, Japan) | 31cm Refl. | 14 | images |
| Tomita, Yasuaki | (Gunma, Japan) | 25cm Refl. | 1 | image |
| Yoneyama, Seiichi | (Yokohama, Japan) | 20cm Refl. | 1 | image |
| Yunoki, Kenkichi | (Osaka, Japan) | 20cm Refl. | 21 | images |
Jupiter was generally quiet this month, too. RS was at II:103.0 deg. (Jul. 11, Miyazaki), having core-like darker center and distinct outline. Miyazaki estimated the length of RS on that day at only 15.7 deg., which gave us an impression that became small much more. Dark projections on SEBs edge preceding RS may have collided with RS one after another this month, too, but RS itself was hardly affected, though slight bridges or streaks could be seen on both sides. STrZ dark ring preceding RS became much fainter, and it was difficult to see as a ring except under good condition. On Jul. 23, it was at II:76.6 deg. (Miyazaki), suggesting that it had turned into prograding motion unlike before.
BA was clearly seen as a large oval at II:286.8 deg. (Jul. 17, Einaga). In SSTB, there were five small white spots (A1-A5) and two cyclonic FFRs between them. This month, an elongate FFR between A2 and A3 passed south of BA, but no change in size was observed in BA. In STBn jetstream which had been active in this apparition, five, more or less, dark spots newly formed from STBn dark segment preceding BA. Also in NNTBs, new group of jetstream spots emerged in a sector of II:260-310 deg.
Notable acceleration of white spot was observed following BA. This spot was tangential to south edge of STB dark segment extending following BA, and it originally had typical rotation period for South Temperate Current of 9h55m24.6s (-0.39 deg./day), a little longer than BA. But it suddenly accelerated late in June to -0.90 deg./day. It was equivalent to rotation period of 9h54m03.6s, which belonged to South South Temperate Current as well as SSTB white spots. According to images during this event, an elongate FFR between A4 and A5 was approaching the spot from the following side, and the p. end of FFR arrived at south of the spot just at the end of June. Since then, the spot was trapped by the p. end of FFR, and both markings came to prograde together. On the other hand, similar FFR between A2 and A3 had overtaken the spot from April to May, but no change in motion of the spot was observed, probably because width of the FFR was narrower than the other. It is known that South South Temperate Current sometimes invades South Temperate Region, and it seems that the acceleration of the spot was a similar event.
(August 5, K. Horikawa)
[Fig.1] White spot on STBs edge |
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[Fig.2] Drift chart of white spot on STBs edge |
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