Mon Apr 14, 2025 LEVIATHAN MIRROR
On April 13, 1842, the mirror for the Irish Leviathan was completed. It was six feet across, and was built by William Parsons in Ireland. It was a metal mirror, an alloy of copper and tin. Installed in the fifty-six-foot-long telescope tube, it became the Irish Leviathan, and for the next seventy years, it was the biggest telescope on earth. Parsons observed stars, the moon, and the planet Jupiter. Then the potato famine hit Ireland, and it was shut down. But in 1845, Leviathan was running again and Parsons observed M51, a large nebula in the constellation Canes Venatici. He called it the Whirlpool, describing it as a "spiral nebula". Parsons even saw individual stars in the Whirlpool, and thought that it was a distant galaxy, similar to our own Milky Way. He was right.
Tue Apr 15, 2025 HOW THE BEARS GOT THEIR TAILS
The constellations of Ursa Major and Ursa Minor are in our northern sky tonight. Star charts depict these bears as having long tails, which bears don’t have. In an old myth, Zeus loved the maiden Callisto, but his wife, Hera, turned her into a bear. Now Callisto had a son named Arcus, who when he grew up, ran into his long-lost mother out in the forest. Fearing for his life, Arcus aimed an arrow at her, but Zeus kept him from killing her by turning him into a bear as well. To keep them safe, Zeus grabbed Arcus and Callisto by their short bear tails and dragged them up into the sky, where they became constellations. In the process, he stretched out their tails, which is why they’re so long. You may think that’s stretching a tale a bit, but these are the bear facts.
Wed Apr 16, 2025 MAGNIFYING POWER
“What power is that telescope?" is a question that asks “how much can the telescope magnify” whatever it is you're looking at. But a telescope has a whole assortment of magnifying powers - all you have to do is change the eyepiece. The eyepiece does the magnifying. Most small telescopes should never be taken over 100 to 200 power - the image gets too dim and fuzzy. The telescope’s big lens or mirror has a different purpose. It is collecting as much light as possible. The wider the ‘scope’s mirror or lens, the more light it can gather, which yields a brighter image which can then be magnified more. A lens or mirror that’s four inches across works up to about 200 power, while a 6 inch ‘scope can be pushed to 300 power under good seeing conditions.
Thurs Apr 17, 2025 HOW TO LOSE WEIGHT
If you want to lose weight, move to the equator. Here’s why: The rotating Earth creates centrifugal force - not really a force, just inertia at work. The Earth’s spin hurls us out into space, but gravity holds us back. Earth’s rotational speed is zero at the poles, but almost a thousand miles an hour at the equator. And the Earth is a little fatter around the equator than from pole to pole. So at the equator we’re 12 miles farther away from Earth’s center, and there’s slightly less gravity. This reduces our weight by about two-tenths of one percent from our position here in Florida. So if you weigh 150 pounds and you move to Ecuador, you’ll weigh about a third of a pound less.
Fri Apr 18, 2025 LYRID METEOR SHOWER
The Lyrid meteor shower will reach peak activity over the next few nights. It’s coming out of the part of the sky where we find the constellation Lyra, the Harp, that’s why we call them the Lyrids. This shower isn’t especially strong, but viewing will be pretty good, at least until the third quarter moon rises after midnight. Get away from bright streetlights. Face east, and then look up toward the zenith. You don’t need a telescope to see these momentary bright streaks of light, in fact a telescope would hinder your view. Take a lounge chair to lean back in, dress warmly, and don't forget to protect against mosquitoes and other hazards.
