Director: K. Horikawa, Secretary: Y. Iga
Jupiter was at stationary on Jun 6, and turned to prograding motion. Though it had not passed over eastern quadrature yet (Jul. 2), its altitude dropped below 30 deg. only two hours after sunset, since the difference of celestial declination between sun and Jupiter was large this apparition. This month, we have received observations listed below. Hayashi joined as a new contributor, but number of observations reported was much fewer than that in last month, it was the midst of rainy season. In addition, two images taken by Peach in April were fowarded by Minami, the Director of Mars Section.
| Observer | Location | Telescope | Images/Drawings | |
|---|---|---|---|---|
| Adachi, Makoto | (Otsu, Japan) | 31cm Refl. | 4 | drawings |
| Akutsu, Hiroaki | (Hokkaido, Japan) | 28cm Refl. | 16 | images |
| Akutsu, Tomio | (Philippines) | 28cm SCT | 2 | images |
| Einaga, Hideo | (Hyogo, Japan) | 25cm Refl. | 29 | images, 8 maps |
| Fukui, Hideto | (Shizuoka, Japan) | 25cm Refl. | 13 | images |
| Hayashi, Toshio | (Kyoto, Japan) | 35cmSCT | 6 | images |
| Horikawa, Kuniaki | (Yokohama, Japan) | 16cm Refl. | 7 | drawings |
| Ikemura, Toshihiko | (Nagoya, Japan) | 31cm Refl. | 4 | images |
| Kumamori, Teruaki | (Osaka, Japan) | 60cm Refl. | 1 | image |
| Mishina, Toshiroh | (Yokohama, Japan) | 20cm Refl. | 4 | images |
| Miyazaki, Isao | (Okinawa, Japan) | 40cm Refl. | 10 | images |
| Nakai, Kenji | (Hiroshima, Japan) | 25cm MCT | 1 | image |
| Narita, Hiroshi | (Kawasaki, Japan) | 20cm Refr. | 3 | drawings |
| Pellier, Christophe | (France) | 21cm MCT | 24 | images |
| Phillips, Jim | (USA) | 20cm Refr. | 8 | images |
| Takimoto, Ikuo | (Kagawa, Japan) | 31cm Refl. | 53 | images, 2 maps |
| Tatum, Randy | (USA) | 25cm Refl. | 3 | images |
| Tomita, Yasuaki | (Gunma, Japan) | 25cm Refl. | 3 | images |
| Vandebergh, Ralf | (Netherlands) | 25cm Refl. | 12 | images |
| Yoneyama, Seiichi | (Yokohama, Japan) | 20cm Refl. | 2 | images |
| Yunoki, Kenkichi | (Osaka, Japan) | 20cm Refl. | 41 | images |
Similar to last month, Jupiter was quiet, and little change was seen. Dark streak preceding RS broke during May, and six rugged projections remained following II:20 deg. But these features also disappeared by the end of June, retrograding on SEBs edge. In the meantime, dark ring preceding RS remained unchanged, and it was seen as isolated dark patch as of the end of June at II:78.6 deg. (Jun. 29, Takimoto). Because it had slowly been retrograding, it would collide with RS in due course. RS was at II:103.6 deg. (Jun. 17, Fukui), keeping gentle retrograding motion. It was vivid orangish color with dark core on its center. Faint arch remaining along its southern edge may be the consequence of collisions with projections described above.
BA was prominent oval at II:304.8 deg. (Jun. 11, Hayashi). Though its interior was dusky, it was clearly seen by dark collar. And it was elongate and large, having mean length of 11.4 deg. throughout June. STBn dark section about 40 deg. long preceding BA emerged in the second half of previous month had broken up into a chain of dark spots, which was prograding with jetstream. Most of spots disappeared at or before reaching bluish dark patch (STB remnant) at about II:160 deg., but a few conspicuous ones survived passage and got closer to RS. One spot had reached RS in May, and second spot arrived at RS around June 10. But it seemed that it disappeared there just like previous one.
There were many barges and portholes (small white spots) in northern half of NEB, in which barges were at around +15 deg. in latitude, near to the center of the belt, while portholes were located in NEBn edge at about +19 deg. These spots tended to move as a group of some ones. This month, there were two conspicuous groups, one of them was located II:300-20 deg. and consisted of 3 barges and 4 portholes, the other group was at 210-240 deg. with two barges and 4 portholes, respectively. In addition to these, isolated white spot was seen at 130 deg. As first group had rotation period as short as following one, the spaces between barge and porthole narrowed, and it was becoming remarkable.
On NNTBs edge, many jetstream spots were seen, but it was more difficult to identify individual spot than the previous apparition, because they largely varied in prograding speed and there were some slow-moving spots in adjacent NTZ. STBn was again crowded with spots, as early this month, a chain of 7 dark spots were newly formed in a sector between II:220 and 300 deg.
Saturn will be in solar conjunction on Jul. 24. Though evening sky of Japanese rainy season brought us the poorest condition for observation, we have received report from eager observer.
| Observer | Location | Telescope | Images/Drawings | |
|---|---|---|---|---|
| Yunoki, Kenkichi | (Osaka, Japan) | 20cm Refl. | 1 | image |
During this apparition, Saturn showed not only appearances of white and dark spots with low-contrast but also changes in color and brightness in the vicinity of South Pole. Furthermore, the opposition effect (Heiligenschein phenomenon) was observed in Saturnian ring, and attracted attention of many observers. We expect interesting phenomena for the next apparition.
(July 15, K. Horikawa)