Galileo project, part 1

Bob Jardine

I went to Dino Point on a Thursday, because it looked like the only clear night for awhile. Very nice night. I got 21.25 on my SQM in mid-evening, which is the darkest I've seen there in some time. I also got 21.48 while I was packing up at around 1AM. That's the best reading I think I've ever had from Dino, and I think it is the best reading I've ever had at one of the "local" observing sites. Limiting magnitude was 6.2 for my eyes.

I'm working on several observing projects. One new one that I've just started is the Astronomical League's new Galileo observing project. Since this is the 400th anniversary of Galileo's first astronomical observations, the idea is to repeat them to get an idea of what he observed. The catch is that you're supposed to do these observations at magnifications of 20X or less, as Galileo did.

I decided to combine this project with two other components. One is to construct an approximate replica of one of Galileo's telescopes. Since that construction project isn't finished yet (in fact, it is just underway), I did my first observations last Thursday night using binoculars. I intend to repeat all of the observations with the replica scope once it is complete.

The third component is a re-reading of Sidereus Nuncius (The Starry Messenger), Galileo's first account of his observations. That's obviously a moony and/or cloudy night project, not a project for a night like this one!

Now on to the observing report...

Equipment: Canon 15X50 IS Binoculars. Yes, a tad higher quality optics than G.G. had, not to mention a spectacularly larger field of view. But most of my current telescopes don't go as low as 20X, so binoculars it is.

Here's what I observed:

1. Venus. The idea is to observe Venus across a good part of its cycle and sketch the phases and sizes.

2. Saturn. The idea is to observe Saturn to see what the rings look at low power; Galileo saw "ears" or "cup handles", not rings. At 15X I wasn't able to detect anything except an obviously non-stellar disk. Maybe once the rings open up enough, something else will be visible.

3. The Pleiades. Here the idea is to sketch the field. The point is to note how many more stars are visible with optical aid. Galileo's sketch isn't very acurate, due to his small field of view. It is easy to do better, and comparing these sketches is an interesting exercise.

4. The Lamda Orionis cluster. Ditto.

5. Comet Lulin. It seems like everyone observed this comet on Thursday night! It was very large and obvious in the binocs. A big round fuzzball. I also observed it in George Feliz's scope -- a very nice view, with lots of tail.It was also visible nekked-I (if you know what I mean and I think you do) after it got up a little ways in altitude. The idea in this case is to sketch the field on several different nights to show the comet's motion.

That was it for the Galileo project for this night. In the future, I'll repeat many of these targets, especially Venus, Saturn, and the comet. In addition, the project calls for observing and sketching our moon, Jupiter's moons (of course), and sunspots, none of which were visible on this night, and some others targets.

This project is lots of fun.

For more details on the Astro League's Galileo project, visit:

http://www.astroleague.org/al/obsclub/galileo_club/galileo_club.html

Joe Bob sez: check it out!