It's that time of the year that Jupiter starts to become visible in the evening at a convenient hour. Having had a successful first run of Mars pictures with my little Philips ToUCam Pro webcam attached to my 8-inch Newtonian telescope, tonight is the first time I have imaged Jupiter with it.
Jupiter, with Europa & Io. 9 Apr 2004, 22:20BST (21:20UT)
A blue #80A filter enhances the contrast of the cloud belts and allows the Great Red Spot to live up to its name. Without the filter the Spot is harder to see against the yellow background colour of the planet.
Click on the image or here to see a timelapse animation of two images taken half an hour apart. The rotation of the planet and the movement of Io and Europa in their orbits is plain to see. Unlike previous years I have presented this image as it appears in the sky, with North to the top and East to the left. Rotation is therefore from left to right, just as the Earth would be.
The sun shines slightly from the right and until 20 minutes before the shot was taken the shadow of Europa lay on the planet. Could not take a picture to catch it as Jupiter has not yet cleared the eaves of my house, but will attempt to do so soon.
Compared to previous efforts with the much more expensive Minolta Dimage 7 digital camera, the results are astonishing. Plenty of detail can be seen in the planet's cloud belts, including the Great Red Spot, a giant high pressure weather system that has been in existence for over 300 years.
The two innermost Galilean moons show up nicely too...
Jupiter was one of 4 planets I imaged on the same night making a quick tour of the solar system.
Three of Jupiter's moons were in close proximity to Jupiter and each other tonight and were due to pass in front of and behind the planet. The steadiness of the viewing was not too good, and this is reflected in the lower quality of the pictures, but nevertheless I managed to obtain enough images to make a nice sequence showing the celestial ballet.
Jupiter, with all four Galilean moons. 16 May 2004, 23:21BST (22:21UT). Below, a sequence of frames covering just over 3 and a half hours in real time, speeded up 2000 times. The picture above corresponds to frame 4 of the animation, when all the moons are visible against the background of space.
For the first three frames of the sequence Io is hard to see as it lies directly in front of Jupiter itself (in "transit") and I have indicated its position with an arrow. The sun shines from towards the right, so on frame 2 the shadow of Io, visible as a small black spot, starts to track across Jupiter at the same rate. On frame 4 Io itself has emerged to the right of Jupiter.
Europa moves the other way, from right to left, and disappears behind Jupiter at 23:12UT. It is therefore no longer visible in the final frame, taken at 23:14.
Ganymede is initially off to the right, but comes into shot on frame 3.
Callisto, like Io, moves from left to right as it heads towards Jupiter, and starts its transit at 23:12. In the final frame it is therefore just visible as a bump on the left hand side of Jupiter as it lies half on and half off the planet.