Cassini, The Grand Finale

Today is 15th of June and in exactly 3 months the spacecraft Cassini will finish its 20 year mission, crashing into Saturn’s atmosphere. As the mission continues it’s diving while orbiting Saturn, it is giving us the best images we have ever seen and providing unique and new information of the ringed planet. This is how I ended up wanting to share my first observation of the Cassini Division, the biggest gap between the rings A and B. This is also my last entry from China because in exactly one week we will be moving to US and looking for new adventures, new skies and more fun.

I usually try to share a sketch that shows a realistic eyepiece view, but this time I am going to share the original raw sketch made in the field, while I was observing through the eyepiece. To have a reference of the equipment, I was using my Celestron 6SE tube with my most powerful eyepiece, a 9mm Celestron X-Cel LX (166x).

This observation was made on the 21st of March 2016, more than 3 months after I got my telescope in China. I had seen Saturn before, but honestly I was a little dissapointed because I could not see much detail compared with what I had seen in the beginnings with my Celestron Astromaster 130EQ from Bogota, Colombia.  

That night was special, though. The seeing was good enough that I could throw into the focuser the eyepiece and have a sharp view of Saturn. I kept staring at Saturn for some time and then magically it appears, what I though it was, the Cassini division. It was not very evident, but using averted vision and concentration I could notice a detached piece of ring on both of the edges. I can compare the resolution of the image with a small fracture (or crack) in an X-ray. Doctors could see it easy, but as a patient, one has to know where it is and also what to look for.  This skill is giving by knowledge and experience.  

I sketched it with the most detail I could, adding notes and all kind of stuff that would help me to check later on my computer. When I finished the session and headed back home, I researched for it. It was in fact the Cassini Division, the gap of 4800 kms that was just an small crack in the rings as seen in my telescope and I was seeing it for the first time in live view mode! Funny fact is that it was discovered more than 3 centuries before with a much smaller (only 2.5”) eyepiece but no body could take away my excitement.

Now, you can use a smaller telescope, trying to get it and let the world you replicated Giovanni Cassini’s achievement, but also you can choose to enjoy those amazing images and videos that Cassini's mission has prepared for us. Here is the link: Grand-finale-orbit-guide.

For now I have to say good bye to my wonderful skies in Lijiang and hope US bring us plenty of clear and dark skies.

LG

Edited by Jennifer Steinberg (editor in chief).