The sky during the day was nice, cloud free and a deep shade of blue. The haze from the fires on the west coast had blown away. People in the astronomy club had been complaining about the poor seeing because of the smoke. Both Friday and Saturday had been clear, that and cold!
For various reasons I had passed the first two nights but I didn’t want to miss the final night of the weekend. I started my set-up after 6, taking the pier out and roughly aligned it towards the north. I brought the 8” reflector out and mounted it, balanced it and left it to acclimate.
I sat in the sunshine and read my Sky& Telescope magazine, checking to see if there were any close alignments, occultations or groupings I might want to look for. The night before, Saturday, there had been an occultation of a bright double star but the moon had already dropped below the hillside west of my house so I missed that.
On this night, there would be a re-appearance of Europa from behind Jupiter’s disc. It was listed as happening at 8:04 PM or 00:04 UT. This would be my first target. There would also be a pass of the ISS (International Space Station) a few minutes later.
I uncovered the scope about ten minutes before 8 and drew a sketch of the planet and its moons. Two were situated close together on one side and the third one was by itself on the other side.
I was using an eyepiece which allowed me to see all of the moons with the planet in the center. The clock showed it as being 4 minutes till the re-appearance occurred so I kept a close watch. I had to occasionally bump the tube to re-center the planet. Since I wasn’t using a motor, the planet and its moons slowly drifted across the field of view and when the two moons disappeared, I’d bump them back to the other side to start their drift again.
After a small nudge to bring the planet into center, I noticed a faint spot of orangish light in-between Io and the planet. At first I thought it might be my imagination but as I watched it slowly got brighter. After a minute or so it was as bright as the other three moons.
I find it fascinating to watch as these moons move around their gravitational center. Every night they are in a different location. Seeing one disappear behind the planet or reappear is as exciting (to me) as watching the moon occult a star. Any occultation is fun to watch, they show us the movement of the moon(s) and the earth. It shows us that the objects we observe through our telescopes are not stationary. We just can’t see the motion of the things far away from us. We see this every time we observe through a non-motorized telescope.
So, after watching Europa, the smallest of the four easily seen moons, (just a bit smaller than our own moon!) reappear from the planets shadow, I watched another satellite appear. This was a bit closer, the ISS made a nice pass about 5 minutes later. I had to walk down the street a bit to see it above the hill and the trees off to my west. It showed up right when it was predicted! Another object held in a gravitational grip, spinning around a planet. This satellite was man made and man occupied!
I went back and looked at Saturn and (some of) it’s moons, M57, the Ring Nebula and M31, the Andromeda Galaxy and finally the planet Mars and then it was time to call it a night. It was the end of a good weekend and what better way to end it than by losing myself in the stars.
Occultation-
An event that occurs when one celestial body conceals or obscures another. For
example, a solar eclipse is an occultation of the Sun by the Moon.
Satellite-
A natural or artificial body in orbit around a planet.
1 comment:
Makes me wish I had a telescope
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