Friday, August 04, 2006

then there were 3; no, 4! (Union)

We kicked off the evening watching Jupiter's moons. With the cat 'scope continuously trained on the planet, we watched the moons move. At first there were only 3 visible. Ganymede was hidden in the glare of the planet (it began crossing in front of it at 7:50pm). But, right on schedule, at 9:42pm, it emerged from the limb of the planet, ever so slowly detaching itself, like a blob of water or mercury, a black sliver expanding finally between the two.

This was Jovian first for me.

It was a lot of fun having the laptop right there running RedShift live. The kids, Miranda and Rachel, really enjoyed that. They updated the screen for me. I think David, PJ, and Mom enjoyed the appearance of the moon too. Donna had to leave early unfortunately.

(Moon size increased 5x normal.)

At first, I was looking for Ganymede "in-line" with the other planets. I kept looking in the wrong spot for it...

I was however mildly frustrated that I couldn't see Ganymede itself in front of Jupiter. Is it the one that looks most like Jupiter? Is it the toughest to see without a filter? I also could not see its shadow on the planet. Contrast issues? Again, should I have a filter to enhance that?

We continued watching Jupiter up to 11:04pm.

humidity: 93%
temp: 18°C
pressure: steady
wind: nil
seeing: not bad, very few waves on Jupiter!

It was shaping up to be a great night!

Before everyone trundled off to bed, I turned to some double stars. Mom enjoyed Mizar and Alcor. We noted the yellow versus blue/white colouring.

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