[ FirstLight Astronomy Club ] The Skies Above

« April 2003 | Main | June 2003 »

So You Like Planets?

The Solar System >

Then you've come to the right place --- and time! This week has planets for everyone - early risers and night owls, the patient and the impatient. Let's start in the "early" evening.

Both Jupiter and Saturn are performing their swan song for the year in the western skies. We passed them by on our inside orbit months ago.

Saturn is now so far away it is nearly, but not quite, on the far side of the sun. A keen observer will notice Saturn as the golden yellowish "star" following the sun down in the western twilight skies about 8:30 PM.

Jupiter is still king of the heavens and though now over 525 million miles away can still be seen as a much brighter orb way above Saturn in the early evening skies. If you have a small telescope, you can still pick out its Big Four satellites --- Io, Europa, Ganymede, and Callisto.

That's about it for those of us who hit the sack at reasonable hours. On the other side of the night, just before dawn, the early birds can catch their own planetary worm, so to speak.

If you are up at about 5 AM you can sneak a peak at our two inner neighbors, Mercury and Venus. Believe it or not, they are actually very close in the sky to Saturn (from our perspective on Earth). It's just that Saturn is on the sunset side of the sun. Mercury and Venus are on the sunrise side.

In the northeast at that wee hour you'll easily see the Morning Star, Venus, radiating brightly just above horizon. Regular readers here will recall that Venus is so durn bright because she is relatively close both to us and to the sun and, most importantly, Venus has an all-over cloud cover. Those clouds reflect a lot of the light striking her. In fact she outshines everything in the night sky except that planet-like ball in her neighborhood for the next couple days --- the Moon.

If you have really really good eyes, or better, a pair of binoculars, you can spot Mercury. A tiny dot just to the lower right of Venus, this little guy is tough to see because, unlike Venus, Mercury is pretty small and has no highly reflective cloud cover.

Now for those readers who are up during the middle of the night, the planet party goes on!

Alas, one of the late night planets, poor Pluto in Ophiuchus, is a tough little critter to find, even with a good scope. Hardcore planet hunters can go to skyandtelescope.com and find there a star chart for their adventure.

Neptune and Uranus can both be found with a simple telescope, a star chart, and a little patience. They are now planetary bookends for the big star of the coming summer sky season.

That big star is Mars, rising in the southeast just after 1 AM. You cannot miss it. It is the brightest object in that part of the sky, its reddish tint betraying it as the Red Planet. We are catching up to Mars now as we orbit the sun. It is getting closer. And closer. And closer.

This summer it will be at its closest approach in over 50,000 years! It will be a wonderful Martian summer for us amateur astronomers!

Make a promise to yourself to see with your family at least one of the nine planets this week.

Oh, I forgot to mention one planet; the best and most beautiful, the one you're sitting on. You can and should enjoy that one everyday.

Mark Ritter teaches astronomy at Temecula Valley High School and can be reached at mritter@firstlightastro.com.

Posted by Administrator at 2003.05.26 01:31 PM | Comments (0)

More Red Moons than a Baboon

The Solar System >

At long last we get to experience a cosmic event from the comfort of our home, live from the Moon. This Thursday night the Moon will vanish, only to return again hours later in a sky show called a lunar eclipse.

Just as a way of reminder, the lunar eclipse differs from its more famous and glitzy brother, the solar eclipse. In a solar eclipse, the Moon moves between the Sun and us; we are in Moonshadow then.

This Thursday, however, things are turned around. We are between the sun and moon; we are the ones casting a big shadow on our Little Orbiting Buddy.

Now you may be thinking: Why doesn't this phenomenon happen all the time? The Moon goes around us all year, and every month at Full Moon it's on the opposite side as the sun. Shouldn't the Moon go through our huge shadow much more often?

It's a little more complicated than that. First, the Moon isn't always on the exact same plane as the sun. Sometimes it moves over our shadow just missing it, sometimes it ducks below. So although every month it goes over to where our shadow is, most of the time it misses going through it.

Second, our shadow is a big one, to be sure, but the Moon is one great distance away --- over 230,000 miles out there. Put in perspective, if the Earth were the size of a big grapefruit and the Moon were a golfball, the Moon would be over 200 golfballs away, over 15 feet. The odds of getting that golfball into the shaft of the grapefruit's shadow aren't exactly overwhelming.

But it does happen. And when it does it is a beautiful thing. Here are some things to watch for.

By the time the Moon rises Thursday, it is already in the shadow, so unfortunately we will miss the covering up sequence. But! We can see it uncover throughout the evening.

During the 8 o'clock hour go out and look to the east. If it is a clear sky, you'll notice that as the sun is setting behind you, a great purplish "horizon" will be rising into the sky in front of you. This great arc of rising darkness is the shadow of the Earth streaming out into space. From that darkness you'll see the Moon emerge, by now already fully in the shadow.

If the conditions are right, as the Moon rises it will appear a ruddy copper color. Why, if it's in shadow? Although we cut off the Sun's light to the Moon, our atmosphere is getting into this act.

Our atmosphere can actually bend light like a giant lens. While the blue side of the light spectrum gets scattered pretty easily --- the reason for blue sky --- the red light can make it through.

A person on the Moon during a lunar eclipse sees Earth as a black ball rimmed with a thin red circle of light, an "all-over sunset" if you will. Out atmosphere focuses this red light towards the Moon and reddens it.

In the late 9 o'clock hour you'll see an historic phenomenon. As the Moon passes slowly in its orbit from darkness to light, you'll see the edge of the Earth's shadow is curved. It is always curved, and always has been. Why is this historic? The Greeks, thousands of years ago, noticed this and came to the conclusion that the Earth was the shape that always makes a curved shadow --- a sphere. Yes, ancient people knew the world was round! Clever people, those Greeks.

Until next time, clear skies and happy lunar eclipse!

Mark Ritter teaches astronomy at Temecula Valley High School and can be reached at mritter@firstlightastro.com.

Photo Credit & Copyright: Fred Espenak (courtesy of www.MrEclipse.com)

Posted by Administrator at 2003.05.10 01:35 PM | Comments (0)



Looking for something?	« April 2003 \| Main \| June 2003 » So You Like Planets? The Solar System > Then you've come to the right place --- and time! This week has planets for everyone - early risers and night owls, the patient and the impatient. Let's start in the "early" evening. Both Jupiter and Saturn are performing their swan song for the year in the western skies. We passed them by on our inside orbit months ago. Saturn is now so far away it is nearly, but not quite, on the far side of the sun. A keen observer will notice Saturn as the golden yellowish "star" following the sun down in the western twilight skies about 8:30 PM. Jupiter is still king of the heavens and though now over 525 million miles away can still be seen as a much brighter orb way above Saturn in the early evening skies. If you have a small telescope, you can still pick out its Big Four satellites --- Io, Europa, Ganymede, and Callisto. That's about it for those of us who hit the sack at reasonable hours. On the other side of the night, just before dawn, the early birds can catch their own planetary worm, so to speak. If you are up at about 5 AM you can sneak a peak at our two inner neighbors, Mercury and Venus. Believe it or not, they are actually very close in the sky to Saturn (from our perspective on Earth). It's just that Saturn is on the sunset side of the sun. Mercury and Venus are on the sunrise side. In the northeast at that wee hour you'll easily see the Morning Star, Venus, radiating brightly just above horizon. Regular readers here will recall that Venus is so durn bright because she is relatively close both to us and to the sun and, most importantly, Venus has an all-over cloud cover. Those clouds reflect a lot of the light striking her. In fact she outshines everything in the night sky except that planet-like ball in her neighborhood for the next couple days --- the Moon. If you have really really good eyes, or better, a pair of binoculars, you can spot Mercury. A tiny dot just to the lower right of Venus, this little guy is tough to see because, unlike Venus, Mercury is pretty small and has no highly reflective cloud cover. Now for those readers who are up during the middle of the night, the planet party goes on! Alas, one of the late night planets, poor Pluto in Ophiuchus, is a tough little critter to find, even with a good scope. Hardcore planet hunters can go to skyandtelescope.com and find there a star chart for their adventure. Neptune and Uranus can both be found with a simple telescope, a star chart, and a little patience. They are now planetary bookends for the big star of the coming summer sky season. That big star is Mars, rising in the southeast just after 1 AM. You cannot miss it. It is the brightest object in that part of the sky, its reddish tint betraying it as the Red Planet. We are catching up to Mars now as we orbit the sun. It is getting closer. And closer. And closer. This summer it will be at its closest approach in over 50,000 years! It will be a wonderful Martian summer for us amateur astronomers! Make a promise to yourself to see with your family at least one of the nine planets this week. Oh, I forgot to mention one planet; the best and most beautiful, the one you're sitting on. You can and should enjoy that one everyday. Mark Ritter teaches astronomy at Temecula Valley High School and can be reached at mritter@firstlightastro.com. Posted by Administrator at 2003.05.26 01:31 PM \| Comments (0) More Red Moons than a Baboon The Solar System > At long last we get to experience a cosmic event from the comfort of our home, live from the Moon. This Thursday night the Moon will vanish, only to return again hours later in a sky show called a lunar eclipse. Just as a way of reminder, the lunar eclipse differs from its more famous and glitzy brother, the solar eclipse. In a solar eclipse, the Moon moves between the Sun and us; we are in Moonshadow then. This Thursday, however, things are turned around. We are between the sun and moon; we are the ones casting a big shadow on our Little Orbiting Buddy. Now you may be thinking: Why doesn't this phenomenon happen all the time? The Moon goes around us all year, and every month at Full Moon it's on the opposite side as the sun. Shouldn't the Moon go through our huge shadow much more often? It's a little more complicated than that. First, the Moon isn't always on the exact same plane as the sun. Sometimes it moves over our shadow just missing it, sometimes it ducks below. So although every month it goes over to where our shadow is, most of the time it misses going through it. Second, our shadow is a big one, to be sure, but the Moon is one great distance away --- over 230,000 miles out there. Put in perspective, if the Earth were the size of a big grapefruit and the Moon were a golfball, the Moon would be over 200 golfballs away, over 15 feet. The odds of getting that golfball into the shaft of the grapefruit's shadow aren't exactly overwhelming. But it does happen. And when it does it is a beautiful thing. Here are some things to watch for. By the time the Moon rises Thursday, it is already in the shadow, so unfortunately we will miss the covering up sequence. But! We can see it uncover throughout the evening. During the 8 o'clock hour go out and look to the east. If it is a clear sky, you'll notice that as the sun is setting behind you, a great purplish "horizon" will be rising into the sky in front of you. This great arc of rising darkness is the shadow of the Earth streaming out into space. From that darkness you'll see the Moon emerge, by now already fully in the shadow. If the conditions are right, as the Moon rises it will appear a ruddy copper color. Why, if it's in shadow? Although we cut off the Sun's light to the Moon, our atmosphere is getting into this act. Our atmosphere can actually bend light like a giant lens. While the blue side of the light spectrum gets scattered pretty easily --- the reason for blue sky --- the red light can make it through. A person on the Moon during a lunar eclipse sees Earth as a black ball rimmed with a thin red circle of light, an "all-over sunset" if you will. Out atmosphere focuses this red light towards the Moon and reddens it. In the late 9 o'clock hour you'll see an historic phenomenon. As the Moon passes slowly in its orbit from darkness to light, you'll see the edge of the Earth's shadow is curved. It is always curved, and always has been. Why is this historic? The Greeks, thousands of years ago, noticed this and came to the conclusion that the Earth was the shape that always makes a curved shadow --- a sphere. Yes, ancient people knew the world was round! Clever people, those Greeks. Until next time, clear skies and happy lunar eclipse! Mark Ritter teaches astronomy at Temecula Valley High School and can be reached at mritter@firstlightastro.com. Photo Credit & Copyright: Fred Espenak (courtesy of www.MrEclipse.com) Posted by Administrator at 2003.05.10 01:35 PM \| Comments (0)
	Powered by Movable Type 3.14