More on Jupiter

I couldn't get back to sleep after writing the last entry. I kept wondering if that extra dot I saw when looking at Jupiter really was Neptune. So, I got up and did some more research. It turns out that was I saw was NOT Neptune. They are not yet close enough together to be in the same field of view. Instead, what I was looking at was Mu Capricorni, a 5.0 magnitude star about 90 light years away.

To figure that out I went into my Starry Night software, found Jupiter and backed it up to about 5am this morning. Here's what it gave me after zooming in a bit:
Note that this image is NOT inverted (because Starry Night doesn't give that option, as far as I know). This is pretty much exactly what I saw, so the object above Callisto clearly wasn't Neptune. Too bad.

But, this result begs another question. This morning I clearly saw Io, Europe and Callisto. Where was Ganymede? According to Starry Night I should have seen it there off to one side of Jupiter along with the others. Instead, I saw this:
Io, Europa and Callisto. No Ganymede. This is taken from the Sky & Telescope tool. So, where was Ganymede? This puzzled me until I saw this on the S&T tool:
The times noted are in military time, and also using Greenwich Mean Time, so I have to subtract 5 hours to get my local time. So, early this morning, a few hours before I woke up, Ganymede was visible on one side of Jupiter, then it passed behind Jupiter, then it was visible again on the other side and then it passed into Jupiter's shadow, becoming eclipsed and invisible. At least that's how I interpret the text above. I'm still new at this.

The S&T moon tool accounted for this eclipsing, but the Starry Night software did not. If I had been outside at 4am instead of 5am I would have seen this:
Except, of course, that my image would have been inverted left to right because I'm looking through a refractor.

So, that solves the mysteries of "Was that Neptune?" and "Where's Ganymede?" I guess I'll have to wait a few more weeks until Jupiter and Neptune are visible in the same field of view.

But now, at least, I know where Neptune is. Using Starry Night and zooming out a bit gives you this:
If I get up really early again soon, I can use my wider field eyepieces to find it now. Fortunately the two planets will linger together in the sky for a while because, even though Jupiter moves faster than Neptune, they are going to begin retrograde motion in the coming weeks, increasing the amount of time they will appear near each other.

Ok, curiosity satisfied. Maybe now I can get some more sleep.

sigh... except the kids will be waking up soon. Too bad I have to work tonight. Ugh.