Below: special contrast processings of this disturbance.The pictures at the top are the same image with different contrast levels,while the pictures below were taken 5 min. later:

Below: small dark spots or condensations at the SEB-S as found on Nov. 30,  2006.Note its group appearance.(R 610nm filter):

Below: same type of spots,but now captured on Dec. 22,  2006.Again,they create a small group of spots.(R 610nm filter):

May 05, 2007,20:44-20:49 UT CM3=158-161)At the rotational p side,one of the dark SEB-mid/south dark spots is visible,as well some weaker structures in the SEB.Image at left: with arrow,in the mid: higher contrast,Right; enlargement;

(May 23, 2007; 20:34-20:38 UT (CM3=344-346)2 typical SEB-s dark spots with one close to the CM at L3=340.Second spot F. of it,with comparable size and appearance.This was the last observations of this apparition.Itīs interesting that this kind of dark SEB-s spots are observed only begin and end apparition.

April 27, 2007; At least 2 dark spots are visible at the south-side of the SEB.They tend to give the SEB-s a structured appearance.Especially the more-frame gif (below,right)gives a remarkable view.This type of spots seems first observed since early apparition (Nov 7,  2006 and some smaller SEBs spots until in December)with approximately similar type disturbances,also with one bigger spot as part of a group.Obvious is that they are observed very early and late in apparition only,with a relative steady and quiet SEB in mid-appariton and during opposition(aside the mid-SEB white spots).

Below; (partial)enlargements of the April 27 red light shots,but this time more saturated in contrast, show the more cloudy character in the concerning region.Very interesting is the comparison of the north with the south side(south is up)in which the northern SEB part looks clearly more flat,against a 'cloudy' south-side.

Regularly,small dark spots are visible at higher latitudes,such as within the STeB or higher.They not seem to tend in groups,like the small spots which we sometimes see at the SEB-s.Though,their appearance and size seems comparable.

April 17;  2 remarkable dark spots are visible in the R 610nm images,they appear at the same longitude in the region between L3=2-3)in the STeB and the SSTeB:

Observations of light structures and storms in 2006/2007:

The most exciting events like large white spots in the Equatorial Zone are rare,but regularly, they seem to appear in a time period of about 30 years. The last big storms were visible in 1903 , 1933 , 1960 and 1990.This period corresponds interestingly with the orbital period of Saturn and the reheating of the northern hemisphere.Why it does not happen with the southern hemisphere reheating is unclear.As a visual observer, I experienced the 1990 storm with a 6cm(2.4inch) refractor.It was the best visible detail on the planet with this limited aparture.

Images obtained on April 10,  2007(CM3=92-105) show definite cloud structure, in the Southern part of the Equatorial Zone(EZ),visible moving clearly with the rotation in the animations below.The turbulent shape of the EB as reported earlier,seems to be connected with this activity within the EZ.North is up this time(R 610nm images taken with ATK-1HS-11);

Overview of observations of small dark spots,condensations or disturbances in the SEB,during the months November and December.All the reported spots did move with the rotation in animations.Some notes: The SEB-s, southern part of the SEB,and bordered to the STrZ,seems to be the main place for the emerging of these spots,concerning the SEB and generally.Another remarkable note is that these spots seem to appear mostly in groups.The overview shows that they appear over the whole length of the Saturn globe,although the biggest and most interesting spots are found at a certain region of longitude.At that time around L3=290.Unfortunately,the weather conditions did not allow further observations of this longitude,to determine a drift rate:

http://www.kk-system.co.jp/Alpo/kk06/s061226rp.jpg

white EZ / EB spots (plumes)

Beside the rare big storms in the EZ which start as a compact but very bright spot,visible with even small backyard telescopes, are every apparition some smaller EZ spots there.These are mostly white spots,rather plumes then white ovals.Jupiter shows similar spots in its EZ. Because the zone is considerably bright itself, the spots are generally not very contrasty but are relatively easy detectable in a normal contrast image.They are visible well at red wavelengths,which is an advantage considering the less influence of seeing in this area.Recent observations show that in some cases,when the white spot is located maximum low of latitude,it can form partially a 'bay' within the EB,and this can increase its visibility.

below: example of a spot located just at the edge of the EZ and the EB.The spot forms a bay within the Equatorial belt. Observation from February 2,  2006:

click here for an animation showing this spot together with the big STrZ storm on Febr 2,  2006.Note also the small SPR white oval:

http://img213.imageshack.us/img213/4435/s20060202ebezws4af3.gif

Clearly a chain of white EZ spots was found in red light images obtained on Nov 7,  2006,see below.Position is in the EZ-n, the northern part of the EZ which is just visible well with the current ring-position.The spots seem to form bays in the nothern edge of the EB also.The animation shows them moving with the rotation.

below right: normal contrast: 05:10 UTC   CM 3 = 294

link below: the complete visible EZ-n seems structured,as seen in this negative featured animation from images taken Nov 7,  2006.Visible is a fixed pattern which moves clearly with the rotation:http://img214.imageshack.us/img214/2995/sateznspots20061107brd7.gif

white spots in the SEB / NEB

The SEB is currently the most obvious belt on Saturn,already easy to see in the smallest telescope.It's in fact composed of different smaller belts,but darker and more concentrated at its northern edge in the observing period 2006/2007.In moderate telescopes it's possible to see some structure sometimes,mostly caused by brighter spots disturbing the belt.Here is an observation of a typical low contrast SEB-zone white spot on Dec 14,  2004:

2  long existing obvious spots are visible in this image obtained through a red filter (610nm) on February 1, 2006:

They appear actually in the 'space' between the 2 darker north and south edges of the SEB (SEBn and SEBs).This region is called the SEB-zone (SEBz)The spots are relatively easy to photograph due to the high contrast and the fact that they are visible well in red light images which are generally less deteriorated by seeing.

Below: white SEB-zone spots captured in a one-shot color image on Febr 2,  2006:

Below: white SEB-zone spot early in the season,captured on Nov 7,  2006 in the very active region around CM 250-300 system 3.Red light R610nm images in fair seeing:

February 4,  2007; Area of a big white spot in the South Equatorial Belt,together with an interesting disturbance,which appears as a waving line from the southern SEB edge to the north side of the SEB.This is visible in both images taken 6 minutes apart,see red box.It's suspected that this is a further development of the moderate disturbance found in the November 7,  2006 images which has drifted to another longitude in the meantime(see chapter dark spots).Images taken in the red light at 610nm in a very short clear moment between clouds and mist.

March 28,  2007; a white spot in the SEB-zone is captured in these red light images at L3=340.It's probably the same spot,unchanged in appearance as the one captured on Febr 4 at L3= 355/357.This would mean the spot has drifted approximately 0.30 degr/day in the P(rotation) direction.(system 3).ATK-1HS/R 610nm images).

tropical storms / white ovals

Very interesting bright spots appear regularly within the STrZ (South tropical Zone)for example,recently in 2002 and early 2006.These are mostly white ovals.The STrZ (at about -35° latitude)is a very active region for the emerging of these oval spots.Some big storms seem to appear regularly and are possibly a rebirth of the same storm.Possibly,the storm is still there in the quiet periods,but too weak to see with normal equipment from the Earth.Although they can be visible well in red light images,it can be interesting to watch these spots at other wavelengths,and the appearance of the early 2006 STrZ-storm has learned that finding the right wavelength can even be necessary to observe the spot at all at certain stages.

Jan - April  2006:  storm in the STrZ and STeB

A particular interesting spot appeared around January 23,  2006 at the edge of the STeB and STrZ. It was first detected by the Cassini-probe,orbiting Saturn,but at that time on its night-side.Cassini's Radio and Plasma Wave Science (RPWS) instrument detected radio-emisions from lightning flashes,and not much longer, Earth-bound observers found an obvious and compact STrZ-spot.It was the same area and in fact it was a very big lightning storm.This spot remained its compact stage until mid February approximately and then became rapidly fainter and elongated.The spot disapeared early April in most images.

After imaging the spot a few times, a drift rate was found and I used this information to find the right Central Meridian and thus the right time to image,to trace the spot again, even after the regular periods of cloudy weather sometimes for weeks.Unfortunately,most of the observations had be done in poor to very poor seeing conditions,but the spot remained visible in higher contrast images.

Interesting about this spot,which is actually one in the category of white oval spots (WOS) were the photophysical properties; although the spot was still visible well in a red light image just after its emerging,it wasn't in the later images.The spot had changed color,as it seemed to get good contrast only in green light images later.This 'color-change' is probably connected with its changing appearance.

click here for an animation showing the spot in a red filter (R610nm) image,also my first capture of the spot on Jan 29,just some days after emerging,but unfortunately taken in poor seeing:

http://www.kk-system.co.jp/Alpo/kk06/s060129d2.gif

Below: I had a first good opportunity to capture the storm on Febr 2,  2006; at the end of the session, the spot came just into view.

For an animation click: http://www.kk-system.co.jp/Alpo/kk06/s060202b2.gif

Such a long duration of more then 2 months is exceptional for a spot of this kind.It was an extraordinary occasion to study the effects on the spot which certainly occur due to the long existance,the rotation and other factors.Just as expected,the spot became more elongated through the months.It wasn't bright anymore after February,contrast with the surroundings became low and the poor seeing in this period made the observations not easier.

below: left; The storm was even captured in very poor seeing on March 2, 2006.This nicely illustrates how obvious it was.Right: negative observation on March 14 in also poor seeing.Despite this,the spot was live visible on screen.

Around mid-March the spot was pretty large fanned out and it appeared to disturb surrounding higher latitude belts and zones,especially the STeB, but even slightly the STeZ.

below: the STrZ-storm on March 15, taken in fair seeing conditions.Note the obvious disturbance by the spot of at least 2 other belts/zones, south from the STrZ.The 2 smaller windows show a special contrast processing.The moon directly below Saturn(north side) is Tethys.

Below: animation showing the spot moving together with moon Tethys:

Click here for an animation showing the spot just moving out of view (limb leftside) together with 4 moons: http://www.kk-system.co.jp/Alpo/kk06/s060312a3.gif

Below: interesting comparison of the STrZ-spot between early February,when the spot was in the early compact stage,with the situation during mid-March.This represents nicely the result of what happens to a spot when it exists for such a long time:

A selection of images showing an overview of the spot's morphology can be found here: http://alpo-j.asahikawa-med.ac.jp/kk06/s060405rp.jpg 

animation: http://www.kk-system.co.jp/Alpo/kk06/s060405rp.gif

Overview-animation of the transition of the storm made from images during the 2 -3 months of visibilty:

A definite white spot in the STrZ was found in images,obtained on Nov 30,  2006.The feature appears in high contrast red light images.Its appearance looks very much like the later stages of the STrZ-storm from early 2006.At the moment, it's not sure whether this is a rediscovery of this storm-remnant in the new apparition or a new feature.Longitude of the feature is at L3=240.Images: 05:40 UTC / 05:45 UTC. CM system 3= 240/243.(R 610nm).

Additional Saturn observations and facts:

Color image taken on December 22,  2006 under conditions varying from fair-good to very good.Obvious is a clear cyan color of the STeZ which is nice contrast with the South Polar Region at the southern side,and the STrZ at the other side.Lr-RGB image with ATK-1HS/Tcam PCVC750k):

recent changes of belts and zones

These images show the incredible changes in atmospheric structure at high southern latitudes between late 2004 and early 2006 (south on top)especially the South Polar Region, in both colors and structure.Another interesting difference is the thickness of the STeB.We can also interpret that as a smaller STrZ in 2006 compared to 2004(left: Nov 24, 2005, Right: Febr 2, 2006).Click for an animation:

http://www.kk-system.co.jp/Alpo/kk06/s060401rp.gif

some words about technique

All color images are obtained using a 25cm(0.25m)Newtonian reflector with a ToUcam PCVC 740k for the older images and a ToUcam PCVC 750k camera at f/24 for the newer ones.For spectral images also an ATIK instruments ATK-1HS camera is used.The degree of processing is mostly depend on circumstances like seeing quality and /or contrast of the feature.So when a spot appears to be very weak, a stronger processing is mostly applied.In that case, the rings can actually be snipped off,as images processed on maximum disk detail are mostly not suited to show good ring detail in the same image.

color observations of the Saturn atmosphere

Below: Beautiful differences in color on the Saturn globe,very rarely seen but were obtained thanks to an exellent steady air on Nov 24,  2004.The thick dark belt at 1/3 of below is the SEBn, northern and at that time darkest part of the SEB. Note the subtle color differences within this band.This is changing constantly.According to the color-differences we could divide this SEBn in an SEBn-north and SEBn-south,in which the SEBn-s looks blue and the SEBn-n is yellow-red.The mid-SEBn seems more brown-colored.The bright band below in the image is the EZ,with the EB in its mid.The EB has a brownish-red color here.Note also the orange color of the STeB at 1/3 from above.The appearance of this belt has changed a lot,see the comparison above.Another nice detail is the color difference of the STrZ with the STeZ,which looks more bluish.The typical brown-green to green-bluish color of the South Polar Region don't need to be noticed.Don't use this image as a reference to recent images.As you see in the comparison, everything is changing!(one-shot color ToUcam-rawmode image).

detail within the rings

While the Cassini-division is visible in almost all circumstances, the smaller detail like subdivisions within ring B or the Encke-division require a good seeing and a telescope with minimal 8 inch aparture.What we see from the Earth as 'subdivisions' in ring B,are actually additions of many unsolved rings A 6 inch planetary Newton can show already good detail within the B-ring.A good indication of acceptable seeing to observe smaller divisions is the bright ring just at the outside of the Cassini-division.According to own visual observations on Nov 24 , 2004 in exceptionally good seeing and with the rings still good opened,the Encke-division seems to be the most obvious structure visible beside the Cassini-division,especially at very high magnifications( 800x - 1500x on a 10 inch telescope).The moons except Titan remain pinpoints even above 1200x magnification.The shadings in the B-ring as seen in the ccd images were best seen at powers of 300-400x as they need more contrast.This image was obtained at the same night,but still does not approach the visual impressions: