Friday, September 21, 2007
For amateur astronomy (and layman's information on celestial events of interest), go to Revolving Rock. For flora, fauna, and amateur naturalism, the new blog will be Biotic Spark.
If you're wondering the reason for the change, it's basically this: I'm exploring the possibility of establishing a wider readership at both blogs, for the eventual purpose of being able to market astronomy- and biology-related "products", one day down the road. (For example, I've noticed that there is at present a lack of interesting science-related toys.)
I will continue to update my Google Reader and del.icio.us feeds with websites of interest. If you want to follow those, there's a site dedicated to that here.
If I ever decide to have a blog with just personal updates and musings on things, I would call it "Peltz the Blog", and it would be found here. FYI.
And have you noticed that there are a lot of funny video clips these days? I have. And so, in keeping with this blog-happiness, there is now also a site dedicated to that.
Wednesday, August 22, 2007
Here's the real advice, with elaboration below each point:
1. You want to see the Moon when it's in the umbra, not the penumbra.
There are two parts to any shadow, and this includes the one cast by the Earth: there's the lighter, outer shadow (called the penumbra) and the darker, inner shadow (called the umbra). The effect of Earth's penumbral shadow being cast on the Moon is extremely subtle. So subtle, in fact, that I guarantee you won't notice it. So if you're checking a time table for the lunar eclipse, you'll want to make sure you find out when the Moon first comes into contact with the umbra, not the penumbra. Otherwise you'll find yourself sitting there for over an hour waiting for anything appreciable to occur. I say this out of personal experience (I once went to some length to pack my telescope and drive far out into the country for a "total" lunar eclipse, only to learn that some "total" lunar eclipses are entirely penumbral, i.e. hardly noticeable. Absurdly, this means that there are some partial lunar eclipses more worthwhile than total ones!)
2. To observe this eclipse, you're gonna need an alarm clock, a pot of coffee, and, if you're east of the Pacific Time Zone, a tolerance for slight unfulfillment.
For locations in North America this Tuesday's lunar eclipse occurs in the early morning hours. In fact, for everywhere except the Pacific Coast, the umbral eclipse is beginning in the pre-dawn hours, as the Moon is approaching moonset. Now I don't mean to discourage anyone from trying to go out to see it (quite the contrary!)... it's just that I want to issue this disclaimer, lest I get anyone's hopes up:
Unless you live far out in the Pacific Ocean, you're going to have to get out of bed real early. Additionally, the further east of the Pacific that you live, the lower in the sky (and closer to the time of sunrise) the eclipse event is going to occur, and the Moon will actually set while the eclipse is still in progress.
3. If you own a pair of binoculars, or a small telescope, use it.
But, that said, if you don't, don't fret. Your naked eyes will do just fine.
4. For your convenience:
Here's the time schedule, culled from NASA's Total Lunar Eclipse of Aug. 28, 2007 webpage for when the Moon approximately begins to enter the umbral shadow, and when it completely leaves it:
Eastern Daylight Time: Begins to enter at 5:52 am; completely leaves by 7:22 am
Central Daylight Time: Begins to enter at 4:52 am, completely leaves by 6:22 am.
Mountain Daylight Time: Begins to enter at 3:52 am; completely leaves by 5:22 am.
Pacific Daylight Time: Begins to enter at 2:52 am; completely leaves by 4:22 am.
As I said, for most observers the moon will set while the eclipse is in progress. But if you're curious, you can find Moon- (and Sun-) rise and set data by entering your location and the date (Aug 28) in the following form available at the U.S. Naval Observatory's Complete Sun and Moon Data for One Day.
5. You're not crazy if you do in fact get out of bed to go watch this.
Who cares what your boss thinks about the bags under your eyes? You directly observed the sphericity of the Earth, man! You saw the light of the sum of all sunrises and sunsets! You're one of those rare lovers of the world and all its splendid phenomena!
6. But you are kind of crazy...
You lunatic! I mean did you notice the time tables above--that's insanely early! And it's a worknight, no less! Lunar eclipses are not so rare that it's not like you won't have another chance in your life to see some more, blah blah blah...
(I leave it to your speculation to decide where I'll be early Tuesday morning.)
Sunday, August 12, 2007
There are always two lunar eclipses per year, some of them total, some of them only partial, and not all of them visible from your location.
If you appreciate experiences of cosmic proportions, you'll find total lunar eclipses especially very beautiful. Not only are they a rare opportunity to directly observe the sphericity of that big rock you call home, but they're also the only way you can experience the sum of all sunrises and sunsets happening on Earth at one moment. (That's why the Moon turns that eerie shade of red-orange! Think about it...)
So, you may find it worth your while to set your alarm and crawl out of bed to have a peek. (Did I mention it was early on Tuesday, Aug. 28? Heh. For example, here in southern California, the eclipse doesn't begin until 1:51am, and the Moon won't enter totality until 2:52am.) You can find eclipse information for your locality here at NASA's Eclipse Page.
Saturday, August 11, 2007
The Earth is making its yearly passage through a drifting path of debris left by a comet named Swift-Tuttle. The result? The annual Perseid meteor shower takes place!
You can probably expect to see 30-40 meteors per hour if you're viewing late tonight (Saturday); 45 per hour late Sunday night, and up to 80 per hour in the wee hours of Monday. For comparison, on a normal night any other time of year, the average rate is just 2-3 meteors per hour.
Naturally, the darker the skies, the more meteor streaks you're going to be able to see.
Why is this shower called "the Perseid shower", you might wonder? The meteors are entering the Earth's atmosphere in a small area in the direction of the constellation Perseus. This means is that if you trace the direction of the meteor streaks backwards, you will observe that they are "emanating" from Perseus. But you don't need to focus your gaze on any particular place in the sky to see them--just lie down and look around. (Reclining lawn chairs are a meteor-watcher's best friend.)
However, it may be the case that the higher in the sky Perseus is, the more meteors you are going to be likely to see. In other words: the later you view, the better. For locations in central and eastern North America, Perseus will be an "acceptable" altitude of 20 degrees above the northern horizon by 9pm to 10pm (an hour to two hours later if you're further west). If you're familiar with the W-shaped constellation of Cassiopeia, Perseus is just "below" that. The Stellarium screenshot below shows Perseus (far right) in relation to Cassiopeia, the Big Dipper (at far left), and the northern horizon. Click on this image to see a much enlarged version open in a new window:
In my experience,the Perseids are the best meteor shower of the year. Not only are they more numerous than most of the other annual meteor showers, but they occur in summer, a reasonably pleasant time to be outside at night. (Just don't be deceived: take a jacket!). It's especially nice that this year they've conveniently decided to occur on a weekend and a New Moon. : )
So, don't miss it!
(For more information: this article at Sky & Telescope has much of the same information as above, but contains a few additional interesting details.)
Sunday, August 05, 2007
Friday, August 03, 2007
But I was very surprised to hear them just now, sitting here in my classroom planning lessons, because it's three o'clock in the afternoon.
Man are they loud! It's a whole orchestra of howls, concentrated a hundred yards or so away in the scrub along the base of a cliff that runs in front of the school. (So there's little doubt in my mind that it is definitely a pack of coyotes, and not just neighborhood dogs.)
My Google search "Why do coyotes howl?" provided a good clue as to why these coyotes might be howling in the middle of the day: underneath their ruckus, I could hear an emergency vehicle siren in the distance.
It is eerie and forboding to stand outside right now, especially when they are so close. I can't imagine how much more eerie it would be in the dark!
Saturday, July 28, 2007
Reports the SF Sidewalk Astronomers:
"Stargazing is the subject of Seeing in the Dark, a 60-minute, state-of-the-art, high-definition (HDTV) documentary by Timothy Ferris that premieres September 19, 2007 at 8:00 p.m. on PBS (check local listings).
The film, Ferris's third, is based on his book, _Seeing in the Dark_ (2002), named by the New York Times as one of the 10 best books of the year.
Seeing in the Dark will bring the wonders of the night sky in state-of-the-art HDTV to millions of viewers. The program features remarkable high-definition astrophotography, as well as the men and women, professionals and amateurs, who have seen and captured phenomenal images within and beyond our solar system and galaxy. It also explores how inexpensive telescopes, sensitive digital cameras, and the Internet now enable casual stargazers to get in touch with the cosmos.
Like the book, the film is in part a personal account of Ferris' life-long devotion to stargazing, beginning with his introduction to the night sky as teenager in Florida in the '50s.
'Seeing in the Dark is meant to alter, inspire and illuminate the lives of millions,' said Ferris. 'It introduces viewers to the rewards of first-person, hands-on astronomy--from kids learning the constellations to amateur astronomers doing professional-grade research in discovering planets and exploding stars. I hope it will encourage many viewers to make casual stargazing part of their lives, and a few to get into serious amateur astronomy.' "
Via Matthew Ota, Orange County Astronomers mailing list.