A rare clear interval on Tuesday evening at the observatory and I put my modified webcam on the 20″ with a narrowband infra-red filter. The seeing wasn’t up to much but I got some pictures both with and without a x2 barlow.
The southern cloud band that so dramatically disappeared last year is back although in this image it does appear to have a gap in it where it’s still obscured by higher level clouds.
Once every year the Earth overtakes Jupiter on the inside track and as Jupiter is opposite to the Sun in the sky this is known as Opposition. As the planetary orbits are not circular, the inter-planetary distance varies each year and this year Jupiter is the closest it’s been since 1963. Additionally, for Northern hemisphere observers it’s also higher in the sky than it’s been for many years and this results in a clearer view as there’s less of our atmosphere in the way. To add additional interest this year, the southern equatorial cloud belt has disappeared although it’s just beginning to make a comeback.
Also in this picture, the moon Ganymede has just re-appeared from behind Jupiter.
This image was taken on Tuesday evening with the club 9.25″ Celestron SCT with a 2.5x PowerMate and modified Phillips SPC900 camera. It’s a stack of about 1000 frames processed in Registax.
Friday evening at the Observatory was spent showing some visitors around. As it was clear we were able to look at Venus, Mars, Jupiter and Uranus as well as the Moon through the 20″. Although the planets were all very low and suffering from massive amounts of atmospheric dispersion they went away happy.
After that, it was down to the main business of the night, measuring periodic error on the 20″ drives. This shows that we have some more work to do to stop drift on the altitude drive and also that we have about 7 arc seconds peak to peak periodic error on the azimuth axis.
By this time, Jupiter was high in the sky so we finished up putting my modified Philips webcam on with a 2.5x PowerMate for some video images. Jupiter is more favourably positioned for Northern hemisphere observers than it has been for many years and it was nice to see it at a decent altitude with lots of detail visible in the eyepiece.
With Jupiter so prominent in the evening sky it’s hard to take pictures of anything else. Saturday night was clear and I stayed out to image the moon Io crossing in front of the planet. Unfortunately, a fundamental error meant I inadvertently left the f/6.3 field flattener on the telescope and didn’t notice until I’d packed up at 12:30 and this has spoiled what otherwise may have been reasonable images.
Best of the lot is this one, an RGB composite of about 700 frames of each colour .
My first opportunity to photograph a moon shadow on Jupiter occurred on Tuesday evening as Calisto moved out from the planet just after dusk. The ’seeing’ was pretty bad so I used the 9.25 Celestron without the x2 barlow and used the IR filter again. This f/10 combination enabled me to keep the individual exposures fairly short with a 10 fps framerate (the IR filter doesn’t let a great deal of light through!).
The final image is a stack of about 1500 frames (from an original video of 2300 frames). The Great Red Spot is also visible just to the right of the shadow.
Friday night was forecast to clear before midnight so I made the trip over to the observatory to setup the Celestron 9.25. Right on cue, the clouds cleared (first time that’s happened in a long time) and I got quite a few 3 & 4 minute videos with the webcam and a narrow band IR filter (742nm). This is the result from the last video of the evening at about midnight, 800 frames stacked in Registax 5 with some additional processing in GIMP. Click on the image for a larger view.
This image shows more detail than I’ve captured before and I put this down to the better than average seeing and a slight tweak to the telescope collimation. Jupiter is very close to opposition and has an apparent diameter of almost 50 arc seconds at the moment. The Great Red Spot is just creeping into view just below the equator on the left hand side.
Another evening photographing Jupiter. This time with the BAS Celestron 925 on the 23rd Jul. Separate red, green and blue avi’s of 45 seconds each were taken, stacked in Registax and then combined in the GIMP (an open source imaging program).
The ’seeing’ was pretty good, but once again, the very low altitude limited the detail in the picture. However, the Great Red Spot is just visible on the right had side of the planet.
Processing a picture taken some 10 minutes earlier shows more of the GRS and comparing the images also reveals the speed that the planet is rotating. This image is in red light only and I’ve flipped it both horizontally and vertically to match convention.
Finally, the opportunity to photograph Jupiter presented itself on a fine Saturday evening. With the current Astronomy Now competition limiting entries to ones produced with telescopes under 4 inches in diameter I decided to try out the BAS 3″ Vixen refractor.
Bad seeing curtailed imaging at midnight but I managed to capture a few sequences with red, green & blue filters. With the planet barely 9 degrees above the horizon, results were never going to be stunning, but some sharpening of a composite image produced the following:
