Director: K. Horikawa, Secretary: Y. Iga
Jupiter passed stationary on May 5, and eastern quadrature on May 31. Though Jupiter still kept high altitude in evening sky, it would be the last month for high coverage observation, because the rainy season of Japan would be coming soon. This month, we have received observations listed below.
| Observer | Location | Telescope | Images/Drawings | |
|---|---|---|---|---|
| Akutsu, Hiroaki | (Hokkaido, Japan) | 28cm Refl. | 21 | images |
| Asada, Asada | (Kyoto, Japan) | 31cm Refl. | 14 | images |
| Einaga, Hideo | (Hyogo, Japan) | 25cm Refl. | 36 | images |
| Fukui, Hideto | (Kyoto, Japan) | 25cm Refl. | 9 | images |
| Grafton, Ed | (USA) | 35cm SCT | 3 | images |
| Horikawa, Kuniaki | (Yokohama, Japan) | 16cm Refl. | 15 | drawings, 3 images |
| Ikemura, Toshihiko | (Nagoya, Japan) | 31cm Refl. | 8 | images |
| Kazemoto, Akira | (Kyoto, Japan) | 31cm Refl. | 4 | images |
| Kanno, Seiichi | (Yamagata, Japan) | 25cm Refl. | 4 | images |
| Kumamori, Teruaki | (Osaka, Japan) | 60cm Refl. | 2 | images |
| Meiji Univ. | (Kanagawa, Japan) | 21cm Refl. | 1 | imaegs |
| Mishina, Toshiroh | (Yokohama, Japan) | 20cm Refl. | 11 | images |
| Miyazaki, Isao | (Okinawa, Japan) | 40cm Refl. | 50 | images |
| Narita, Hiroshi | (Kawasaki, Japan) | 20cm Refr. | 9 | drawings |
| Oyamada, Hiroyuki | (Hadano, Japan) | 20cm Refl. | 6 | images |
| Tatum, Randy | (USA) | 25cm Refl. | 2 | images |
| Tomita, Yasuaki | (Gunma, Japan) | 25cm Refl. | 4 | images |
| Yoneyama, Seiichi | (Yokohama, Japan) | 20cm Refl. | 9 | images |
| Yunoki, Kenkichi | (Osaka, Japan) | 20cm Refl. | 46 | images |
NEB broadening taken place around II:340 deg. in April was in progress. In II:340-50 deg. shown violent changes in early stage, NEB became about 3 deg. broader than before, forming new northern boundary at +21 deg. in latitude. In the remaining sector, NEB kept the original width between II:90 and 180 deg., following which the belt was somewhat broader bulging up northern edge in about 40 deg. span of longitude. Some of belt darkening phenomena of Jupiter start at a certain longitude and spread rapidly toward preceding or following direction, SEB Revival (SEB Disturbance) and NT Current-C are good examples. But it seems that NEB broadening does not show such a trend.
RS was at II:96.0 deg. (May 27, Akutsu), and it had retrograded about 4 deg. since March. Though it was apparent change due to inequality of limb-darkening near eastern quadrature, it might be real because RS had been almost stationary at II:91-92 deg. in this apparition from November 2003 to March 2004 just after opposition. BA was approaching RS (II:119.0 deg, May 25, Kumamori), and it is estimated to reach f. end of RS early June. It should be noted whether any interaction can be seen.
SEB activity following RS noted by emerging bright spots in April, had ceased soon without developing into major activity. In May, activity of white clouds could be seen only about 30 deg. range following RS. EZs/SEBn disturbance did not show very violent activity this month, too. Bluish markings and irregular white spots were scattered alongside SEBn edge, but almost of these were minor features. SEBn rift was at I:177.2 deg. (May 16, Miyazaki) forming relatively clear bay on SEBn edge, but no oval was seen in EZs. It will be early June that the rift passes north of RS next. There were numerous dark spots and projections on SEBs edge as seen in the last apparitions. Apart from these markings, STrZ contained a few solitary small dark spots, and Miyazaki indicated that one of such spot located at about II:205 deg. were stationary, not moving with SEBs jetstream.
Saturn was gradually decreasing its altitude towards solar conjunction on July 9. It would virtually be the last month of this apparition considering Japanese rainy season. This month, we have received observations listed below.
| Observer | Location | Telescope | Images/Drawings | |
|---|---|---|---|---|
| Akutsu, Hiroaki | (Hokkaido, Japan) | 28cm Refl. | 1 | image |
| Ikemura, Toshihiko | (Nagoya, Japan) | 31cm Refl. | 5 | images |
| Yunoki, Kenkichi | (Osaka, Japan) | 20cm Refl. | 6 | images |
Though delicate small spots were observed almost every month in this apparition, no traceable object was seen in recent months, partly because observing conditions became poorer.
The Cassini spacecraft will arrive at Saturn in coming July, and the Huygens probe will try soft landing on Titan in December. We expect active phenomena on Saturnian surface in the next apparition.
(June 10, K. Horikawa)