The chief astronomer at the Franklin Institute was on NPR last week promoting the "September Skies" program.

I suggested to Jeff that he take Kenny and ... to my surprise ... he did last Friday night!

Jeff rarely thinks that my suggestions are any good, so that's why I was surprised. But, in fact, he admitted that he was as interested in the subject as he suspected Kenny would be.

The 2 1/2 hour program began on the roof, the fifth floor observatory roof, outdoors, at night, in Philadelphia. It was an overcast evening so the outdoor segment was mostly talk. The astronomer offered suggestions for developing a strategy for observing the night sky at home, things like that.

Back indoors, in the planetarium, there was a movie called "The Life and Death of a Star" which showed, among other things, a star's life cycle. Something that I have been trying to explain to Kenny verbally, but I imagine that a visual presentation makes better sense to him at his young age. The images of several constellations were also projected.

Then, the astronomer talked about the upcoming moon mission, Pluto's demotion and that latest deep space probe project or whatever it is.

When he opened it up for questions, Kenny raised his hand, stood up and asked, "Why do stars twinkle but planets don't?"

I suppose that the astronomer had told them how to distinguish stars from planets when they were outside, that one twinkles and the other doesn't, but failed to explain why. Jeff said that the astronomer, of course, had no trouble answering the question and Kenny had no trouble sharing that answer with me when he arrived home. One boy did stump the astronomer with something he asked about "dark matter". I don't think that stumping the astronomer at a free program is so nice.

They gave out disposable "binoculars" but Jeff said that he should have brought his telescope. Next time he will. He seems very eager to return for a related program.