| Observer | Location | Telescope | Images/Drawings | |
|---|---|---|---|---|
| Adachi, Makoto | (Otsu, Japan) | 31cm Refl. | 20 | drawings |
| Akutsu, Hiroaki | (Hokkaido, Japan) | 28cm Refl. | 31 | images |
| Akutsu, Tomio | (Philippines) | 28cm SCT | 15 | images |
| Asada, Hideto | (Kyoto, Japan) | 31cm Refl. | 7 | images |
| Einaga, Hideo | (Hyogo, Japan) | 25cm Refl. | 37 | images, 5 maps |
| Fukui, Hideto | (Shizuoka, Japan) | 25cm Refl. | 10 | images |
| Hatanaka, Akitoshi | (Mie, Japan) | 40cm Refl. | 19 | images |
| Hayashi, Toshio | (Kyoto, Japan) | 35cm SCT | 7 | images |
| Hirabayashi, Isamu | (Tokyo, Japan) | 25cm Refl. | 10 | images |
| Horikawa, Kuniaki | (Yokohama, Japan) | 16cm Refl. | 15 | drawings, 4 images |
| Ikemura, Toshihiko | (Nagoya, Japan) | 31cm Refl. | 21 | images |
| Kanno, Seiichi | (Yamagata, Japan) | 25cm Refl. | 6 | images |
| Kazemoto, Akira | (Kyoto, Japan) | 31cm Refl. | 30 | images, 2 animation |
| Kumamori, Teruaki | (Osaka, Japan) | 60cm Refl. | 13 | images |
| Mishina, Toshiroh | (Yokohama, Japan) | 20cm Refl. | 49 | images |
| Miyazaki, Isao | (Okinawa, Japan) | 40cm Refl. | 42 | images |
| Nakai, Kenji | (Hiroshima, Japan) | 25cm MCT | 3 | images |
| Narita, Hiroshi | (Kawasaki, Japan) | 20cm Refr. | 19 | drawings |
| Pellier, Christophe | (France) | 21cm MCT | 114 | images |
| Phillips, Jim | (USA) | 20cm Refr. | 2 | images |
| Takimoto, Ikuo | (Kagawa, Japan) | 31cm Refl. | 87 | images, 1 map |
| Tatum, Randy | (USA) | 25cm Refl. | 8 | images |
| Tomita, Yasuaki | (Gunma, Japan) | 25cm Refl. | 6 | images |
| Vandebergh, Ralf | (Netherlands) | 25cm Refl. | 25 | images |
| Yoneyama, Seiichi | (Yokohama, Japan) | 20cm Refl. | 14 | images |
| Yunoki, Kenkichi | (Osaka, Japan) | 20cm Refl. | 66 | images |
This month, white spot on NEBn edge was watched with interest by observers. Small white spot Z (WSZ), which had been taken up in previous reports, was colliding and merging with another spot.
WSZ was formed in 1997 as an aftermath of NEB broadening started in second half of 1996. During this event, many anticyclonic white spots (portholes) and cyclonic dark spots (barges) appeared together, and WSZ was only one spot among them. Although other spots disappeared within a few years, WSZ has survived for almost 10 years overcoming NEB broadenings which took place twice since then, recording unprecedented longevity as such markings.
The rotation period of WSZ was fairly shorter than System II, though it has much varied for every apparition from 9h55m17s (-0.57 deg./day) to 9h55m34s (-0.16 deg./day). As a result, it has already drifted nearly two times around the planet. Since other spots in the same latitude have slower drift rate close to System II, WSZ has often overtaken preceding barge and 'destroyed' it, but it has never been observed that WSZ encountered with similar white spot. The only example on merger of anticyclonic spots on NEBn edge was observed by NMSUO in 1966-67 apparition. Also in that viewpoint, this encounter was notable as very rare phenomenon.
This apparition, WSZ marked almost the fastest prograding speed of -0.57 deg./day, and observed as an outstanding spot larger than other portholes. On the other hand, WSY was a younger spot which probably formed in last apparition, and had slower prograding speed (-0.12 deg./day). Though two spots were about 50 deg. apart in March, they approached rapidly and the distance of them decreased to less than 10 deg. in mid-June. After Jun. 20, two spots presented a motion swinging around each other; WSZ moving northward while WSY moving southward. And at last, they became apparently single spot on Jun. 27, when the spot had a small bulge on its preceding-south. This bulge could correspond to WSY, and it moved to following-south side of the spot on Jun. 29. Though they were expected to merge swinging around each other, Miyazaki's image on Jul. 1 showed a tiny spot at a distance from WSZ. If it was WSY, this event was not a merger, but merely 'an overtaking'. In the subsequent images, however, a single elongate oval was seen again. As this event would be still in progress, you should look forward to the next report.
(2) Saturn
Saturn was rapidly decreasing altitude toward solar conjunction on August 7. This apparition has substantially come to an end soon after start of rainy season. We received the last observation of this apparition from the following observer.
| Observer | Location | Telescope | Images/Drawings | |
|---|---|---|---|---|
| Yunoki, Kenkichi | (Osaka, Japan) | 20cm Refl. | 1 | image |
The last observation of this apparition was made by Yunoki on Jun. 3. Saturn will appear again in the east sky late August or early September. We expect Saturn will be active in the next apparition, too.
(July 11, K. Horikawa)
(Translated on October 31)
[Fig.1] Encounter of NEBn portholes, WSZ and WSY |
 |