| Observer | Location | Telescope | Images/Drawings | |
|---|---|---|---|---|
| Akutsu, Tomio | (Philippines) | 35cm SCT | 75 | images |
| Carvalho, Fabio | (Brazil) | 25cm Refl. | 8 | images |
| Einaga, Hideo | (Hyogo, Japan) | 30cm Refl. | 11 | images |
| Fukui, Hideto | (Shizuoka, Japan) | 35cm SCT. | 3 | images |
| Go, Christopher | (Philippines) | 28cm SCT | 22 | images |
| Horikawa, Kuniaki | (Yokohama, Japan) | 16cm Refl. | 4 | drawings |
| Ikemura, Toshihiko | (Nagoya, Japan) | 38cm Refl. | 6 | images |
| Kumamori, Teruaki | (Osaka, Japan) | 20cm Refl. | 9 | images |
| Wesley, Anthony | (Australia) | 33cm Refl. | 20 | images |
| Yoneyama, Seiichi | (Yokohama, Japan) | 20cm Refl. | 8 | images |
This month, new activity in SEB preceding RS was reported. On Mar. 8, Einaga, Ikemura, Kumamori and Wesley observed that a conspicuous white spot had emerged in mid-SEB preceding RS (II:97.2 deg.). Then, the spot was drawn to east-west direction, and was deformed into light band which inclined from preceding north to following south direction, peculiar to this belt. As white clouds activity took place in dark SEB, mid-SEB outbreak is well-known. Most of them took place at the longitude following RS, and outbreak started at preceding side of RS was a few instances, such as 1998. As of the end of March, active region extended to 30-40 deg. in longitude, but it may be finished as a small-scale outbreak, since few bright spots were seen.
Two dark spots in STrZ which are suspected to be the remnants of STrD were observed as distinct large spots. The preceding spot (DS1) was at II:167.4 deg. (Mar. 30, Akutsu), and the other one (DS2) was at II:229.6 deg. (Mar. 21, Go). While DS1 was slowly prograding with -0.3 deg./day, DS2 had a faster drift rate of -0.4 deg./day, which was close to LEBS. Both spots had typical dark ring aspect having white cores at their center in high resolution images, and was light even in methane band images. Therefore, it is suggested that they have anticyclonic circulation, which is the same as the predecessors observed in this latitude.
A conspicuous dark spot was observed on SEBs edge preceding RS. In Einaga's image on Mar. 8, it was typical dark ring projecting into STrZ at II:77.0 deg. Probably, it was formed in mid-February, and was retrograding at about +1 deg./day unlike two LRSs mentioned above. By Mar. 27, it reached II:97.8 deg. (Go), immediately preceding RS. It was expected that the spot will go into RS bay early April, and will merge going around RS. Because it is the first time that SEBs spot encounters RS since SEB Revival took place last year, we have to take notice of this event.
EZ became light this apparition, containing fewer prominent festoons than previous apparition. Also, EB was almost invisible in some longitudes.
Recent NEB tends to vary its width every 3-4 years. This apparition, the belt became narrow, retreating northern edge. It is behind the above cycle considerably, since previous broadening event took place in 2004. Alternate dark barges and small white spots (notches), peculiar pattern to this stage, were developing along NEBn edge. As NEB became narrow, many projections were formed on NEBn edge by dark barges at about +17 deg. in latitude, while notches at about +20 deg. in latitude were left in NTrZ. Long-lived NEBn oval WSZ was at II:341.7 deg. (Mar. 31, Carvalho). It decelerated when NTBs outbreak occurred last year and had halted around II:60 deg., but it regained original drift rate of about -0.5 deg./day this apparition.
(2) Saturn
Saturn which had just passed the opposition in February was retrograding at the immediate east side of Regulus, and was in good period for observation. This month, we received observations listed below.
| Observer | Location | Telescope | Images/Drawings | |
|---|---|---|---|---|
| Akutsu, Hiroaki | (Hokkaido, Japan) | 28cm Refl. | 6 | images |
| Akutsu, Tomio | (Philippines) | 35cm SCT | 3 | images |
| Asada, Hideto | (Kyoto, Japan) | 31cm Refl. | 18 | images |
| Fukui, Hideto | (Shizuoka, Japan) | 35cm SCT. | 1 | image |
| Go, Christopher | (Philippines) | 28cm SCT | 9 | images |
| Ikemura, Toshihiko | (Nagoya, Japan) | 38cm Refl. | 4 | images |
| Kanno, Seiichi | (Yamagata, Japan) | 25cm Refl. | 1 | image |
| Kazemoto, Akira | (Kyoto, Japan) | 31cm Refl. | 7 | images |
| Kumamori, Teruaki | (Osaka, Japan) | 20cm Refl. | 10 | images, 1 animation |
| Mishina, Toshiroh | (Yokohama, Japan) | 20cm Refl. | 4 | images |
| Nakai, Kenji | (Hiroshima, Japan) | 25cm MCT | 9 | images |
| Takimoto, Ikuo | (Kagawa, Japan) | 31cm Refl. | 17 | images, 1 animation |
| Tomita, Yasuaki | (Gunma, Japan) | 25cm Refl. | 1 | image |
| Yoneyama, Seiichi | (Yokohama, Japan) | 20cm Refl. | 17 | images |
| Yunoki, Kenkichi | (Osaka, Japan) | 26cm Refl. | 29 | images |
Long-lived STBn white spot declined rapidly this month. Although it was observed as a large distinct oval on Mar. 10 in Kumamori's image, it became diffuse and dim after that. The last observation of the spot (*) was on Mar. 18 at about III:315 deg. (Go). Instead of it, a new white spot emerged on STBn edge at about III:280 deg. The first observation of our section was made by Kazemoto on Mar. 17, and Go's image on Mar. 18 showed both spots together, though low contrast. The initial longitude of new spot as well as its tiny bright aspect was very similar to first spot. Therefore, it is likely that two spots were formed by a series of activities which have source region around here. We should pay attention to this region whether similar spots will repeatedly emerge in future.
*) The spot survived and was observed in April, though faint.
Besides the above spot, white spots were observed in SEBZ, one is at III:40.7 deg. (Mar. 11, T. Akutsu), and the other one was at about 10 deg. (Mar. 15, Kumamori). Also, T. Akutsu's image on Mar. 11 showed a tiny white spot in SSTZ. However, these all were single observation, and not confirmed in other images.
(April 13, K. Horikawa)
(Translated on May 29)
[Fig.1] New activity in SEBZ preceding RS |
 |