Director: K. Horikawa, Secretary: Y. Iga
It has been one month since solar conjunction on Jan. 24, and 2009-10 Apparition has started. We received observations listed below, in spite of poorest condition.
| Observer | Location | Telescope | Images/Drawings | |
|---|---|---|---|---|
| Akutsu, Tomio | (Philippines) | 35cm SCT | 1 | image |
| Fukui, Hideto | (Shizuoka, Japan) | 35cm SCT | 1 | image |
| Horikawa, Kuniaki | (Yokohama, Japan) | 16cm Refl. | 1 | drawing |
The first observation in this apparition was made by Akutsu on Feb. 16, and followed by Fukui and Horikawa on Feb. 21. They observed the longitude of RS by chance. While domestic condition was poor, infrared image by Akutsu whose observation site is Philippines showed features of Jupiter.
RS was dusky but somewhat faint. Because of an infrared image, it may actually be quite dark. Though its surroundings were slightly shaded, RS has recovered from Hollow without arch or streak, and STrZ was light preceding RS. SEB was barely seen double preceding RS without turbulences. In EZ, there were two distinct festoons. It seems that EZ has recovered a normal aspect from lightened event in the last apparition, when such features were very few. NEB was the darkest belt on the planet. It was somewhat narrow, and northern edge was flat without barges. NTrZ was light and NTB was a distinct belt.
Saturn will be at opposition in March, and it is in the period suitable for observation. This month, we received observations listed below.
| Observer | Location | Telescope | Images/Drawings | |
|---|---|---|---|---|
| Akutsu, Tomio | (Philippines) | 35cm SCT | 6 | images |
| Fukui, Hideto | (Shizuoka, Japan) | 35cm SCT | 4 | images |
| Go, Christopher | (Philippines) | 28cm SCT | 5 | images, 3 animations |
| Hayashi, Toshio | (Kyoto, Japan) | 35cm SCT | 2 | images |
| Kumamori, Teruaki | (Osaka, Japan) | 20cm Refl. | 7 | images, 3 animations |
| Mishina, Toshiroh | (Yokohama, Japan) | 20cm Refl. | 1 | image |
| Nakai, Kenji | (Hiroshima, Japan) | 25cm MCT | 1 | image |
| Pellier, Christophe | (France) | 25cm SCT | 18 | images |
| Takimoto, Ikuo | (Kagawa, Japan) | 31cm Refl. | 1 | image |
| Tyler, Dave | (UK) | 28cm SCT | 4 | images |
| Yamada, Masahiro | (Tokyo, Japan) | 20cm SCT | 1 | image |
| Yoneyama, Seiichi | (Yokohama, Japan) | 20cm Refl. | 6 | images |
| Yunoki, Kenkichi | (Osaka, Japan) | 26cm Refl. | 33 | images |
The tilt of the ring exceeded -2 deg. at late Feb., turning to increase again, after it reached local minimum late December. Because the ring became wide to north and south, every images showed the interior space of the ring at both side of Saturn's body. and Cassini's Division was visible in high resolution images.
On Saturn's surface, white spots were frequently observed this month too. EZn white spot, which emerged last month, was still prominent, especially in red light. It located at around I:125 deg. on Feb. 10 in Kumamori's image, and at I:136.8 deg. on Feb. 22 in Akutsu's image (measured by Akutsu). These measurements indicate that this spot was retrograding. Since it was at about I:85 deg. early January, drift rate of the spot exceeds +1 deg./day.
On the other hand, on the opposite side of EZ, dusky shadings projecting from SEBn edge into EZs were observed by Yunoki on Feb. 2 and by Akutsu on Feb. 18. The longitudes of these markings in System I were quite different, but System III longitudes were very close at 50-60 deg. So, it may be possible that these were identical marking moving with System III in spite of being in EZ. Though another similar marking observed in January had the same trend, it seems to be different one, because it was at about III:265 deg.
Transits of Titan across Saturn's disk were again observed on Feb. 8 and 23. Go's images on Feb. 8 showed the moment of Titan's egress from Saturn. Interestingly, Titan was seen as a ring like doughnut in the limb darkening of Saturn. Probably, this is because strong limb darkening arises on Titan itself due to dense atmosphere. On the fact that Titan was invisible in methane image on Jan. 23 when it was in transit across Saturn, Akutsu indicated that it was because wavelength of methane band was absorbed by Titan's atmosphere containing methane.
(March 12, K. Horikawa)
(Translated on October 30)