The Dutch Observatory

Following the partial occultation of Europa by Ganymede, I made some images of Jupiter.  The seeing was very variable during the session and probably peaked at average, but here the best image.

On May 8th 2009 Anthony Wesley in Australia captured the Gallilean Moon Europa eclipse the moon Ganymede.  To my knowledge this was the first time an amateur captured the complete occultation of two Gallilean moons in an animation.  My attempts to do the same since than have been hindered by weather conditions on the dates that such event was visible from my location, until this morning.  Here my capture of Ganymede (front and larger) partially occulting Europa, while Io is visible at the right starting to make its turn at the end of its orbit.  Not as good as Anthony’s, but I am happy with the result and waiting for another opportunity.  The sequence consists of 14 images between 6:49 UT and 7:21 UT.  Each image contains approx. 250 out of 500 frames 1/11 sec each stacked in Registax 5 and post processed in Photoshop. Seeing was variable during the capture series and probably peeked at average.  Click the image to activate the animation.

The Clear Sky Clock did forecast bad transparency from 1:00 a.m.  until 3:00 a.m.  However, in reallity at 3:00 am it was clear as a bell, but when I finished setting up, clouds had moved in.  Initially scattered, but soon broken.  so imaging was a challenge.  I ended up taking the red and green channels from one run and combined them with the blue from the previous.  The end result is not too bad.  In addition, I was lucky that at that time the GRS was about to transit the CM and Europa was leaving the preceding limb.  Lots of activity in the NEB with spillovers into the NTrZ, notable 2 dark spots, while two dark interactions with the EZ can also be observed while some light storms in the SSTB seem to reach out in the STZ.

Saturday evening I tried to image Saturn, however, the transparency and stability were so bad that I am not going to post this image.  Instead, I imaged Jupiter on Monday morning.  The transparency and stability was not bad but got worse as time went on.  So here Jupiter with the GRS on June 22, 2009 while the conditions still were good.

This morning I was able to image again.  The Clear Sky Clock misled me again, instead of transparent, stable and good seeing conditions, high cloud bands kept moving in and out, leaving just sufficient time to complete one set, but with reduced IR frames.  This image shows Jupiter with Ganymede on the left and Callisto on the right. 

This morning expectations were great for observing from our location.  Both Ganymede and Io were to transit Jupiter, together with a GRS transit.  However the weather had other ideas.  Light haze at the surface and high cloud bands kept Jupiter moving in and out together with variable seeing.  I only got one complete run to process but with a limited number of frames.  The image shows Jupiter with the GRS just moving onto the planet on the left, Ganymede to the left of Jupiter,  Io just below the GRS and both moon’s shadows on the right.

This morning the GRS was transiting Jupiter.  We had the first clear morning in a few days, but the rain we had made it very humid.  The field accross my house was competely white from the fog.  The GRS looks pale, and the storms in the NEB and the NTropZ seem more organized in this image.

Jupiter on June 2nd.  Today we had a dubble transit with an added feature, the two moons Ganymede and Io were transitting the planet just before Io’s shadow left. I also made an animation with 4 images, with the shadow on two of them.  1 1/4 hours before this image, Ganymede did partially eclipse Io.