Saturn: Opposition 2005 - 2006

13th November 2005

My first Saturn image of the new season. Saturn was still quite low in the east, about 25 degrees up. Thus the air wasn't too steady.
The most obvious thing about the image is just how much the rings have closed up since last season.

2nd January 2006. 00:45UT.

The seeing on this night was excellent, hardly any "wobble" in the air (not surprisingly, by the morning we had fog). Saturn was also pretty high in the sky. This all conspired to give me one of my best ever Saturn images. The image clearly shows four of Saturn's moons and if you look very carefully you can see two more. Roll over the image to see the moons labelled.
Details of the moons are given below:

The lower image is the same image fully labelled.

I also noticed a "small" white spot in the temperate zone of the planet in this image. I wasn't entirely sure if this was a feature or just an imaging artifact. However the image by Jan Timmermans made almost exactly two rotations later (22:16UT) possibly shows the same feature. Mouse over the image to see it arrowed and decide for yourself. I have stretched Jan's image to make the possible spot more obvious.

Click Here to visit Jan's excellent site.

26th January 2006

Just less than one day before opposition and the rings of Saturn are noticeably much brighter than usual. The effect is known as the "opposition effect" (surprise, surprise) or the "Seelinger effect". I was unable to image Saturn at opposition which occurred at about 10:48pm on the 27th of January due to total cloud cover.

Also worth a note is the colour of the north polar cap which is now becoming visible from behind the rings. The blue colour is a result of the north polar cap having been in the ring shadow and therefore the area is much colder than the rest of the planet.

8th February 2006 (Left)

Pretty reasonable seeing this night. The shadow of the planet on the rings is becoming again just over a week after opposition. The rings are back to their normal colour again.

9th February 2006 (Right)

The air wasn't quite as steady this night and the image shows it. The shadow is noticeably bigger again after just 24 hours.

28th February 2006

Not a bad nights seeing but also not the best. This is a combination of a 6 minute AVI with the Barlow extended by 75mm and a 6 minute AVI with just the Barlow. The smaller image was resized by 155% and combined to give the final image.

The moons are Tethys and Encladeus. Roll your mouse over the image to see the moons labelled.

5th March 2006

The Shadow on the rings is really showing again now we're over a month past opposition. I was really pleased with this image. The seeing didn't look this good, however there were a lot of steady moments which clearly added up to a good number of usable frames.

 Combined image from January 2nd 2006 to March 5th 2006

The tall image opposite is set out as a comparison of all the images I have taken from January to the beginning of March. The main reason is to get a feel for the changes seen on the planet over the space of two months. Features of note are that the ring shadow has migrated south from above the rings to below the rings. Note that the apparent shadow below the rings in January is actually the dimming of light through the C ring (or Crepe ring).
It is interesting to see the planet,s shadow on the rings swap sides from before to after opposition. The Penumbral shadow is also visible on both sides of the rings at the point of opposition.
The sequence makes the comparison of the ring brightness compared to the planet and therefore the "opposition effect" much more noticeable.

It is also worth noting that the south polar region has changed through this period, the last image made on the 5th of March 2006 shows more cloud bands in this region than the image made on the 2nd of January.

Mouse over the image to see some of these details labelled.

Changes from 2005 to 2006

Left is an combined image of Saturn from April 2005 and March 2006. Note the differences in the banding of the planet's clouds and the obvious change in the ring orientation.

March 22nd 2006
The seeing was pretty good again this night. I tried an image of Saturn using athe black and white CCD Vesta and a red filter, which gave some interesting results.
Below I used the same red filtered image for luminance and added the colour componant from the toUcam image. It does some slightly odd things with the colour, but the image is much less noisy.

The Toucam image is my biggest stack ever - over 6000 frames out of a possible 8000+. I used the ability of Registax to process more than one AVI into a single image to achieve this.

Also notice that the north polar cap is less blue than it was. I assume the cap is now starting to warm in sunlight after several (earth) years in the shadow of the ring system

19th April 2006

A series of three images taken on the evening of the 19th of April between 9pm and 10pm.
The seeing was reasonably steady this night.
The third image is in near IR taken with a filter that passes 685nm and above. You can just about see through this filter - very deep red.
Notice the brightness of the crepe (C) ring in IR compared to the visible spectrum.
The LRGB image is a combination of the Vesta visible spectrum image (Luminance) and the ToUcam image (RGB colour)