LtE in CMO #265

From Agustin SANCHEZ LAVEGA

@..............Hi all,

Congratulations for the excellent Saturn images. We have added them to the IOPW page.

Concerning the midlatitude spot. We are currently analyzing our Hubble Space Telescope image records (1996 - 2002) in collaboration with R. French, to study cloud features and motions in Saturn's atmosphere before Cassini arrival. Among them, we know that south latitudes from about -40 to -45 deg, have usually small round spots (dark in red and bright in blue). An example can be seen in the attached images for November 9, 1999, where many spots are present (814 means wavelength in nm -red- and 439 is the blue one). Spots at -42 moved drifted about +1 deg/day and those at -45 at -3 deg/day, both relative to System III.

There has been a HST visit in September by R. French, so perhaps the spot imaged by Grafton is there. We will see in few weeks. This spot seems to be more prominent than others seen at these latitudes, but in any case, according to our HST data, they dissipate in weeks or months. As Grafton said they are difficult to see away from the central meridian.

Next HST visits will be in December, so we ask for your support in surveying for new spots.
For other recent works on Saturn using HST images see our paper in Icarus on the presence in 1994-96 of the northern Ribbon wave (Vol. 158, pg. 272. 2002) and the no presence of an hexagon in the south pole and changes in the southern cap (Icarus in the press). I'll present some of these studies next week at the DPS in Birmingham (Alabama).

Good observations!

(1 October 2002 13:22 +0200 (MET DST))

A SANCHEZ LAVEGA (Universidad del Pais Vasco, Spain)
wupsalaa@bi.ehu.es
Dpto. Fisica Aplicada I
Escuela Superior de Ingenieros
Universidad del Pais Vasco
Alda. Urquijo s/n
48013 BILBAO (Spain)
Tfno.: 946014255
Fax: 946014178

Back to the LtE Home Page
Jump to the LtE Archives
Back to the CMO Home Page

.