Last updated: 13 January 2003
Subject: Shadows on Jupiter (ETX90RA) Sent: Saturday, January 11, 2003 13:09:28 From: email@example.com Hello all, yesterday (10 Jan 2003) I had a wonderful view of two shadows close together on the Jovian disc. At 20:10h UT I slung the ETX in the softcase around my neck and cycled through the snow to a nice dark observing site where a picnic-table was awaiting me and my ETX. At 20:20h UT I had the scope set up and noticed the thing had to first cool down. The scope was brought from an indoor 20 degrees C to a minus 8 degrees C. It had been clear all day, but on arrival some clouds had moved in and my observations of the shadows were done through hazy openings in the clouddeck. At around 21:00h UT through the SP15mm(83X) I noticed a dark spot in between the SEB and NEB on it's way to transite the Central Meridian. The other shadow was still hiding in the poor telescopic seeing. At 21:45h UT, through the SP6.4mm I did notice both shadows. One from Io and one from Europa, the shadow of Io was the one I noticed first. It was much darker (larger too) then the shadow of Europa! The shadows were very near one-another with the shadow of Io being ahead of Europa's shadow. I followed the shadows as they transited the Central Meridian at around 22:00h UT. At about 22:10h UT the shadow of Europa had passed the Central Meridian also, and at 22:20h UT I noticed very clearly that the distance between the two shadows had increased, they were no longer very close to one another. Io had clearly moved ahead of Europa. I followed the shadows until 22:40h UT. The moons themselves were not visible as they were in front of the disc of Jupiter. I find it quite wonderful that such a simple observation actually results in learning about solarsystem objects. In this case Io moving through space faster than Europa does. regards, martyn observing from the NetherlandsMike here: Amazing what the Mighty ETX can do!!!
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