Director: K. Horikawa, Secretary: Y. Iga
Jupiter passed the opposition, and was retrograding in Sagittarius. Because the rainy season was over and real summer has come, we can track details on Jupiter surface under stable atmospheric condition. This month, we received observations listed below.
| Observer | Location | Telescope | Images/Drawings | |
|---|---|---|---|---|
| Akutsu, Hiroaki | (Hokkaido, Japan) | 28cm Refl. | 8 | images |
| Colville, Brian | (Canada) | 30cm SCT | 3 | images |
| Einaga, Hideo | (Hyogo, Japan) | 30cm Refl. | 95 | images, 20 maps |
| Fukui, Hideto | (Shizuoka, Japan) | 35cm SCT. | 29 | images |
| Go, Christopher | (Philippines) | 28cm SCT | 32 | images |
| Hayashi, Toshio | (Kyoto, Japan) | 35cm SCT | 17 | images |
| Hirabayashi, Isamu | (Tokyo, Japan) | 25cm Refl. | 2 | images |
| Horikawa, Kuniaki | (Yokohama, Japan) | 16cm Refl. | 20 | drawings |
| Ikemura, Toshihiko | (Nagoya, Japan) | 38cm Refl. | 33 | images |
| Kanno, Seiichi | (Yamagata, Japan) | 25cm Refl. | 16 | images |
| Kazemoto, Akira | (Kyoto/Okinawa, Japan) | 31cm/50cm Refl. | 25 | images |
| Kumamori, Teruaki | (Osaka, Japan) | 20cm Refl. | 36 | images |
| Mishina, Toshiroh | (Yokohama, Japan) | 20cm Refl. | 11 | images |
| Miyazaki, Isao | (Okinawa, Japan) | 40cm Refl. | 80 | images |
| Nakai, Kenji | (Hiroshima, Japan) | 25cm MCT | 2 | images |
| Narita, Hiroshi | (Kawasaki, Japan) | 20cm Refr. | 4 | drawings |
| Oyamada, Hiroyuki | (Kanagawa, Japan) | 20cm Refl. | 11 | images |
| Pellier, Christophe | (France) | 25cm SCT | 7 | images |
| Takimoto, Ikuo | (Kagawa, Japan) | 31cm Refl. | 45 | images, 1 animation |
| Walker, Sean | (USA) | 18cm Refl. | 5 | images, 1 animation |
| Wesley, Anthony | (Australia) | 33cm Refl. | 9 | images |
| Yoneyama, Seiichi | (Yokohama, Japan) | 20cm Refl. | 32 | images |
| Yunoki, Kenkichi | (Osaka, Japan) | 26cm Refl. | 75 | images |
The encounter event of LRS and RS was published as another report in the previous journal (not translated). So, in the first part, a brief summary is written about post-encounter status of LRS.
LRS re-cohered preceding RS as LRS remnant, after it passed through south of RS, being torn in the east-west direction. Though LRS remnant was a methane bright feature similar to the original LRS, its appearance was a normal white oval with no redness, losing dark ring surroundings. Between RS and LRS remnant, a dark streak was formed, and it was extending as LRS remnant progrades. After July 10, LRS remnant halted about 10 deg. preceding RS. It shifted somewhat northward and turned to retrograding motion around Jul. 15. Finally, it collided with RS from preceding side, and merged into RS. The methane bright area preceding RS completely disappeared by the second half of July.
In late July, RS was almost 'RS Hollow' surrounded by dark bluish arch with prominent reddish core at II:126.9 deg. (Jul. 22, Fukui). Dark streak preceding RS was still faintly seen. It would be the influence of this encounter event that northern edge of RS Hollow was irregular from p. end to center by bluish details.
BA had passed RS and was at II:115.4 deg. (Jul. 22, Fukui) by late July, and was conspicuous as large oval though its redness weakened. STB was dark over tens of degrees in both side of BA. Following BA, dark segment of STB was passing RS as a chain of dark spots, and large dark oval in STZ was outstanding at the f. end of the segment, II:160.5 deg. (Jul. 25, Ikemura).
Other belts and zones are calm, but only SEB was active. SEB was broad nearly twice than narrow NEB, and its interior was disturbed by white clouds. Dark bluish streak developed along SEBs edge following II:300 deg. It was composed of irregular dark spot chain with a length of 170 deg., extending to near RS. It was almost stationary in System II, probably due to northerly position in latitude than ordinary streak which emerges from RS and rapidly extends to preceding direction. Since the p. end of the streak projected a little into STrZ, it appeared in low-resolution images that SEB was broad suddenly there.
Two mid-SEB outbreaks were still active. As to one outbreak preceding RS, the source region prograded to II:30 deg., and disturbed white band which lay on northern part of SEB extended to around II:300 deg. The other outbreak activity still continued following RS as disturbed SEBZ. It extended beyond II:200 deg. without distinct source region (f. end).
(August 17, K. Horikawa)
(Translated on March 26)