Algedi is October's Star

This month look for the star Algedi in the constellation of Capricornus. Algedi, or Al Gedi, means the Goat in Arabic and astronomers know Algedi as Alpha Capricorni. However, this doesn’t mean Algedi is the brightest star of the constellation. In some constellations, like Capricornus, the stars were named in order of their position, rather than magnitude or brightness. Algedi is one such example. It’s the western most star and therefore received the alpha designation.

The constellation of Capricornus is one of three water constellations in the zodiac. The other two, Aquarius and Pisces, are neighboring constellations. The constellation represents a Sea Goat, or an animal that is half fish half goat (a mixed animals like this is called a chimera). The story behind Capricornus is that the Greek god Pan (who was a satyr or human figure with goat legs) was trying to escape the sea monster Typhon. In his panic, he leapt into the ocean at the same time as he was changing himself into a fish. However, he only completed half of the change and only managed to give himself a fish tail.

Algedi is a double star that is wide enough to see with the naked eye. However, binoculars will bring out the pair even better. Algedi is an example of a double star where the pair is not actually orbiting each other. Algedi is a chance alignment that looks very close together from Earth but is actually hundreds of lights a part. The fainter, more western of the pair is 690 light years away and the brighter one is 109 light years away. Both stars are G class, just like our sun. However, unlike our sun, the two stars are older, larger, and heavier. The fainter left star is larger and brighter then the eastern pair of the stars.  
   
Look for Capricornus and Algedi in the low in the south after it gets dark. The constellation is not bright and there’s only one reasonably bright star in that part of the sky, Fomalhaut. Look for Fomalhaut low in the southeast and then turn your attention slightly higher and to the south. You’re looking for a pattern of stars that looks like a grin. The constellation will stand out, once you locate it.

Algedi in Capricornus the Seagoat

Transcript: September 27th to October 3rd

RACHEL
Welcome to Idaho Skies for the last week of September. We’re your hosts, Rachel...

PAUL
...and Paul.

RACHEL
Idahoans get to watch the last half of a total lunar eclipse on the night of the 27th.

PAUL
As the moon rises at 9:00 PM, it will be in the middle of its eclipse.

RACHEL
And the moon will remain within the darkest part of Earth’s shadow, or the umbra, until 9:23.

PAUL
After that, you should begin to see the edge of the moon slowly beginning to brighten.

RACHEL
The moon starts leaving the outermost edge of Earth’s shadow, which is called the penumbra at 10:27.

PAUL
That means the eclipse will become pretty much unnoticeable by 11:00 PM.

RACHEL
This month’s lunar eclipse is special for several reasons.

PAUL
First of all, this is the Harvest Moon or the first full moon after the autumnal equinox.

RACHEL
We associate the Harvest moon with pumpkins, so seeing a coppery red lunar eclipse is very fitting.

PAUL
The second reason this lunar eclipse is special is because it’s the closest full moon to Earth for 2015.

RACHEL
That means the moon will appear larger and brighter than on average.

PAUL
So grab a lawn chair and a pair of binoculars as the sun sets on the 27th.

RACHEL
Have you ever wanted to learn how to locate Aries the Ram?

PAUL
Then let the moon be your guide on the night of the 29th.

RACHEL
Aries will appear above the moon as three stars arranged in a slight curve.

PAUL
The brightest star of Aries is called Hamal and it’s an orange giant star 66 light years away from Earth.

RACHEL
Some 2,000 years ago, the star nearly marked the location where the sun appeared on the first day of spring.

PAUL
Or the Vernal Equinox.

RACHEL
Because Earth wobbles on its axis like a top, the Vernal Equinox now occurs one constellation over in Pisces the Fishes.

PAUL
In another 24,000 years, the Vernal Equinox will occur once again in Aries the Ram.

RACHEL
If you can stay up until after 11:00 PM, then you’ll find the moon near two bright star clusters, the Pleiades and the Hyades on the 30th.

PAUL
Both are excellent objects for your binoculars, which will let you see a couple of dozen stars in each, as opposed to half a dozen or so you can see with just your eyes.

RACHEL
Things get even more interesting on the night of the 1st.

PAUL
That’s when you’ll find the moon passing through the Hyades star cluster.

RACHEL
So get your binoculars out.

PAUL
The whole scene, the stars of the Hyades and the moon will fit comfortably within your binoculars.

RACHEL
This might also be a good target for your digital camera if it can remain opened for a few seconds.

PAUL
If you attempt to photograph the passage of the moon through the Hyades, then use a tripod to keep your camera rock steady for several seconds during the exposure.

RACHEL
That’s Idaho Skies for the last week of September. Next week four morning planets will attract our attention.

PAUL
Be sure to follow us on Twitter at Idaho Skies for this week’s event reminders and sky maps.

For Idaho Skies this is Paul...

RACHEL
...and Rachel.

PAUL
Dark skies and bright stars.

Lunar Eclipse: September 27th

We had an attractive lunar eclipse on Sunday evening. The moon rose deeply immersed in Earth's shadow and the red glow of the eclipse grew stronger as the sky got darker. Earth's atmosphere was overall cloudy or not clear, since the eclipsed moon was a dull red rather than bright coppery-red.

Still, a nice treat overall.

Here are three of the pictures I took of the eclipsed moon using a digital camera. The camera's zoom was set to its maximum six power. I used a camera tripod and cable release to keep the camera steady during the exposure.

Now the sad news, Idaho doesn't get to see a total lunar eclipse until 2018.

Shortly after Moonrise

The red light of all of Earth's sunsets is becoming visible.

Darker skies and longer exposures bring out more of the moon's red coloring.

Transcript for September 20 - 26

PAUL
Welcome to Idaho Skies for the fourth week of September. We’re your hosts, Paul...

RACHEL
...and Rachel.

PAUL
Hey, the first quarter moon will help you find star clusters and nebulae with your binoculars on the 21st.

RACHEL
They’re located within the band of the Milky Way.

PAUL
To find them, scan your binoculars above and below the right side of the moon after it gets dark.

RACHEL
It’s best to do this in dark skies outside of town.

PAUL
The star clusters will appear as smudges surrounding a small sprinkle of stars.

RACHEL
The nebulae will just appear as smudges of light.

PAUL
While you’re observing these astronomical objects, you might notice that a star pattern resembling a tea pot is located below the moon.

RACHEL
This is the heart of the constellation of Sagittarius the Archer.

PAUL
And the stellar region around Sagittarius marks the location of the center of our galaxy.

RACHEL
Had enough hot weather?

PAUL
Then autumn begins on the 23rd at 2:21 AM.

RACHEL
At that moment, the sun will appear directly above the Earth’s equator.

PAUL
While this is a true statement, the reality is a bit more complicated.

RACHEL
That’s right. The sun does not actually move north and south of Earth’s equator.

PAUL
Yep, instead the tilt of Earth’s rotational axis points towards and away from the sun as we revolve around the sun in the course of a year.

RACHEL
If viewed from outside the solar system, you’d see that Earth’s north rotational axis always points towards Polaris, a fixed star.

PAUL
However, Polaris is not directly above the North Pole of the sun.

RACHEL
This means as Earth travels around the sun, Earth’s axis points in different directions relative to the sun.

PAUL
So when Earth’s rotational axis is perfectly vertical relative to the sun, it’s autumn in the northern hemisphere and spring in the southern hemisphere, or visa a versa.

RACHEL
Which also means the sun is directly above the equator.

PAUL
It also means that the boundary between day and night across Earth runs from pole to pole.

RACHEL
And that gives every location on Earth 12 hours of daylight.

PAUL
After today, our nights will grow longer in duration while the days in the southern hemisphere grow longer in duration.

RACHEL
Do you leave for work early in the morning?

PAUL
Then on Friday morning, the 25th, you’ll see three planets in the east combined with a relatively bright star.

RACHEL
What makes this even more appealing is that Mars and the bright star Regulus will be very close together.

PAUL
The other planets are Venus, which is the bright star above and to the right of Mars and Regulus.

RACHEL
And Jupiter, the bright star below and left of Mars and Regulus.

PAUL
A good time to see them is around 6:00 AM.

RACHEL
That’s Idaho Skies for the fourth week of September. There’s a total lunar eclipse next week, so be sure to tune in for the details.

PAUL
Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com.

For Idaho Skies this is Paul...

RACHEL
...and Rachel.

PAUL
Dark skies and bright stars.

Transcript for September 13 - 19

RACHEL
Welcome to Idaho Skies for the third week of September. We’re your hosts, Rachel...

PAUL
...and Paul.

RACHEL
The moon reappears in the evening sky by the 16th.

PAUL
On that evening and on the 17th, be sure to look for Earthshine.

RACHEL
It’s visible to the unaided eye if the sky is dark.

PAUL
But it’s easier to see through your binoculars.

RACHEL
After detecting the presence of Earthshine, try looking for details on the dark side of the moon.

PAUL
You won’t see craters like you do on the sunlit portion of the moon, but you should be able to see some of the larger lunar maria.

RACHEL
Maria is plural and Latin for sea, as in ocean.

PAUL
The singular form is mare.

RACHEL
Lunar maria are ancient basaltic flood plains, or frozen oceans of lava.

PAUL
They started forming about 3.8 billion years ago after some of the giant building blocks of the planets pummeled the moon.

RACHEL
Astronomers call this time of frequent and massive impacts the Late Heavy Bombardment.

PAUL
The very large craters or impact basins created in the collisions were hundreds of miles across in some cases.

RACHEL
After hundreds of millions of years, lava started welling up from the cracks inside the impact basins.

PAUL
The lava gradually filled the impact basins in sheets of lava miles thick in some cases.

RACHEL
Since the lavas are rich in iron, they tend to be darker than the brighter lunar highlands.

PAUL
That’s because the highlands are rich in a mineral called anorthosite, which is a mineral rich in white-colored feldspar.

RACHEL
The anorthosite is the scum that floated to the top of the once molten moon.

PAUL
Saturn and the moon are very close to each other on the night of the 18th.

RACHEL
Look in the low southwest after dark and you’ll see Saturn only two degrees away from the southern cusp of the moon.

PAUL
That close together means you can see both at the same time in binoculars.

RACHEL
Your binoculars will show some craters in the southern half of the moon.

PAUL
However, they will not show the rings of Saturn.

RACHEL
It takes a magnification of at least 20 power to see the rings.

PAUL
That means a very large and heavy pair of binoculars.

RACHEL
Or better yet, a spotting scope or small telescope.

PAUL
In a small telescope, Saturn appears a distinct yellow in color.

RACHEL
Through a spotting scope, you’ll see Saturn’s largest satellite Titan as a star to the upper right of Saturn.

PAUL
In an astronomical telescope, which inverts images, Titan will appear as the star to the lower left of Saturn.

RACHEL
That’s Idaho Skies for the third week of September. Summer ends next week and we’ll discuss its passing, so be sure to listen in.

PAUL
Be sure to follow us on Twitter at Idaho Skies for this week’s event reminders and sky maps.

For Idaho Skies this is Paul...

RACHEL
...and Rachel.

PAUL
Dark skies and bright stars.

Transcript for September 6 - 12

PAUL
Welcome to Idaho Skies for the second week of September. We’re your hosts, Paul...

RACHEL
...and Rachel.

PAUL
The waxing crescent moon is located above Orion the Hunter on the morning of the 6th.

RACHEL
Orion is an impossible to miss constellations because of its size and overall brightness.

PAUL
In fact, after the Big Dipper, people are most familiar with Orion the Hunter.

RACHEL
When you go out to observe Orion, be sure to look for a row of three stars crossing the center.

PAUL
That’s Orion’s Belt and below it is a short vertical line of stars representing his sword.

RACHEL
Your binoculars will show that the center star of his sword is fuzzy and impossible to focus into a pin point like other stars.

PAUL
That’s because this is the Great Orion Nebula and not a star.

RACHEL
Instead, it’s a massive star forming region in our galaxy.

PAUL
In a small telescope, it takes on a cloudy appearance almost like cirrus clouds.

RACHEL
The moon, Venus, and two star clusters have a celestial meet up early on the 9th.

PAUL
Go outside between 5:00 and 5:30 AM and brilliant Venus will draw your attention to the low east.

RACHEL
You’ll find a thin crescent moon above Venus.

PAUL
Through your binoculars, you should see Earthshine on the dark portion of the moon.

RACHEL
Now scan to the left of the moon and you’ll run right into the Beehive star cluster, one of the nicest star clusters for binoculars.

PAUL
The distance between the moon and Beehive star cluster is just over a binocular field of view.

RACHEL
That means as the moon leaves the right side of your binoculars, the Beehive enters the left side.

PAUL
The other star cluster is M-67 and it’s between Venus and the moon, but closer to Venus.

RACHEL
In fact, if you place Venus at the bottom of your binocular’s field of view, the star cluster will appear nearly in the center of your binoculars.

PAUL
Did you know that Venus is now a binocular object?

RACHEL
That’s right. Normally it’s just a bright pin point of light through binoculars.

PAUL
However, if you let the morning sky get a bit brighter, you’ll reduce the glare of Venus and see that it has a crescent shape.

RACHEL
Holding the binoculars steady against a fence post or other structure will help you see its crescent shape.

PAUL
The only time you can see a crescent Venus through binoculars is when it’s approaching inferior conjunction.

RACHEL
Inferior conjunction is when either Mercury or Venus pass between Earth and the sun.

PAUL
And when Venus approaches inferior conjunction, it’s at its closest to Earth and we see mostly its dark side.

RACHEL
That means it appears at its largest and is crescent in shape.

PAUL
It was after seeing the complete range of Venusian phases that Galileo became convinced of the Copernican Hypothesis.

RACHEL
The Copernican Hypothesis states that the sun and not Earth is the center of the solar system.

PAUL
If you didn’t get enough of Venus, then be sure to look for it on the morning of the 10th.

RACHEL
That’s when the moon is even closer to Venus.

PAUL
But don’t forget to also look for Earthshine on the moon.

RACHEL
That’s Idaho Skies for the second week of September. Next week we’ll talk about Saturn and the moon.

PAUL
Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com.

For Idaho Skies this is Paul...

RACHEL
...and Rachel.

PAUL
Dark skies and bright stars.