Saturn STrZ, STeZ, SSTeZ became brighter and SPR become darker with the blue filter than the previous apparition. I arranged the Saturn images using blue filter by the year from 1998 to 2002 to study (Fig.1).
Saturn STrZ, STeZ, SSTeZ became brighter and SPR become darker with the blue filter than the previous apparition. I arranged the Saturn images using blue filter by the year from 1998 to 2002 to study (Fig.1).
According to these blue band images STrZ, STeZ, SSTeZ had been dark until 2001, so the border SEB and STrZ had been dull, however the change might be occurred in about the past conjunction. That is recently the southern Temperate Zone of Saturn glove became brighter and the border on SEBs became obvious . In addition the dark area of SPR seems to a little expand (see Fig.2).
When the change was occurred is unknown. The continuous observation is needed.
*1 RGB color CCD ICX205AK blue channel image passbaand 380nm - 550nm
*2 CCD ICX205AL monochorome CCD with B390 filter passband 360nm - 500nm
Telescope C11(D=280mm fl=2800mm)
Effective F no :24 to 44
Camera:DimageEx
Exposure 0.33sec or 0.5sec each
Each image is composite of some good frames
Observer:Masahito NIIKAWA Sakai Osaka JAPAN
青画像による土星南半球の変化
昨シーズンに比べると、青画像では、土星の STrZ, STeZ, SSTeZ が明化しSPRが暗くなった。
検討のため、1998年から2002年までの青画像を並べる(Fig.1)。
これらの青バンド画像によると、2001までSTrZ, STeZ, SSTeZは暗く、SEBとSTrZとの境界ははっきりしなかった。
しかし、前回の合のころに変化したようである。
つまり、南温暖帯は明るくなり、SEBsとの境界が明確になり、加えて、SPRの暗領域が少し拡大したように見える(Fig.2)。
いつ変化が生じたのかは定かではない。継続観測が望まれる。