Monday, September 24, 2018

Idaho Skies Transcript for September 24th and 25th

RACHEL
Welcome to Idaho Skies for September 24th and 25th. We’re your hosts, Rachel…

PAUL
…and Paul.

RACHEL
The moon is full on the 24th.

PAUL
Since this is the first full moon after the Autumnal equinox, this means it’s also the Harvest Moon.

RACHEL
Astronomically, there’s nothing special about full moons.

PAUL
They rise close to the time the sun sets, but that’s about all.

RACHEL
However, the Harvest Moon occurs at a time when farmers are typically harvesting crops.

PAUL
And its light provides them with illumination after the sun has set.

RACHEL
Before the time of electricity, this illumination was important.

PAUL
Because it gave farmers additional hours to work in their fields.

RACHEL
Now normally, the moon rises about 50 minutes later each night.

PAUL
But in September, that time is reduced.

RACHEL
That’s because the moon’s apparent path relative to the horizon varies over the course of a year.

PAUL
In September, the moon is on a path that’s not very steep relative to the eastern horizon.
 
RACHEL
Which means the moon’s position appears to shift more horizontally than vertically every night.

PAUL
Because the moon’s light brightens the night time sky, it’s more difficult to make out faint objects.

RACHEL
And that’s a shame this year when comet Giacobini-Zinner is its brightest.

PAUL
If you want to take a gander at this comet, then look for Gemini the Twins in the low east at 2:00 AM.

RACHEL
Castor is the top star of the pair and the comet is just above Castors foot.

PAUL
Or the star at the right end of the chain representing Castor.

RACHEL
That’s Idaho Skies for the 24th and 25th of September.

PAUL
Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.

For Idaho Skies this is Paul…

RACHEL
…and Rachel.

PAUL
Dark skies and bright stars.

Monday, September 17, 2018

Another Lunar Photography Attempt

Still experimenting with camera exposure settings. This was the best I got on the 16th with my cellphone's camera. It's darker in order to prevent the cusp from being over-exposed.



The moon on September 16, 2018

Idaho Skies Transcript for September 21st, 22nd, and 23rd

RACHEL
Welcome to Idaho Skies for September 21st, 22nd, and 23rd. We’re your hosts, Rachel…

PAUL
…and Paul.

RACHEL
Hey, autumn begins in Idaho at 3:54 PM.

PAUL
Astronomers call this the Autumnal Equinox.

RACHEL
Autumnal is obviously a reference to autumn, but what about equinox?

PAUL
Equinox comes from the Latin for equal night.

RACHEL
Wait, the night equals what?

PAUL
Well, it’s the length of night. Its length is equal to the length of the day.

RACHEL
So in other words, the night and day have the same number of minutes.

PAUL
The term was first used by Chaucer in the 1300’s.

RACHEL
It’s in a book that he wrote for his son, Little Lewis.

PAUL
Chaucer’s book was actually a technical manual, the first one written in English.

RACHEL
Or middle English in this case.

PAUL
His book explained how to use the astrolabe, an ancient astronomical device.

RACHEL
The descendant of the astrolabe is today’s planisphere.

PAUL
Many stargazers have seen or even used the planisphere.

RACHEL
It’s a two dimensional model of the night time sky made from two rotating disks.

PAUL
Its outer disk is a window and marked in the hours of the day.

RACHEL
The inner disk is a map of the stars and constellations.

PAUL
And its rim is marked in the days of the year.

RACHEL
By aligning a time of the day to the day of the year, the window rotates to show the position of the stars.

PAUL
That’s Idaho Skies for the 21st, 22nd, and 23rd of September.

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

For Idaho Skies this is Rachel…

PAUL
…and Paul.

RACHEL
Dark skies and bright stars.

Idaho Skies Transcript for September 19th and 20th

PAUL
Welcome to Idaho Skies for September 19th and 20th. We’re your hosts, Paul…

RACHEL
…and Rachel.

PAUL
Mars reached opposition earlier this summer.

RACHEL
Which means it was at its closest to Earth.

PAUL
That closeness also means Mars appeared at its largest and brightest.

RACHEL
For Mars, a planet only half the diameter of Earth, appearing larger than normal isn’t a lot of help for binoculars.

PAUL
But it was significantly brighter.

RACHEL
And in fact, still is.

PAUL
The waning gibbous moon passes just above Mars on the 19th.

RACHEL
You can’t miss the planet with its bright with a distinct yellowish-orange color.

PAUL
Even though Mars was named after various gods of war, its color doesn’t come blood.

RACHEL
Its color comes from iron oxide.

PAUL
Yep, the surface of Mars is rusty.

RACHEL
Over eons, the wind has broken down the rust into a very fine dust.

PAUL
So fine in fact that the weak winds of Mars can loft the dust into the sky.

RACHEL
Which gives Mars an orangish-colored sky.

PAUL
Without that dust, the sky would be black.

RACHEL
That’s because there isn’t enough air in the Martian atmosphere to scatter the sun’s blue light.

PAUL
Earth, on the other hand, as an atmosphere with plenty of oxygen and nitrogen molecules.

RACHEL
And these scatter blue light very strongly.

PAUL
So no matter which way you look up, you see blue light from the sun.

RACHEL
That’s Idaho Skies for the 19th and 20th of September.

PAUL
Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.

For Idaho Skies this is Paul…

RACHEL
…and Rachel.

PAUL
Dark skies and bright stars.

Idaho Skies Transcript for September 17th and 18th

RACHEL
Welcome to Idaho Skies for September 17th and 18th. We’re your hosts, Rachel…

PAUL
…and Paul.

RACHEL
The first quarter moon passed Saturn early on the morning of the 17th.

PAUL
And on the evening of the 17th, it appears to the left of Saturn.

RACHEL
This would be a good night to observe the moon and the region around Saturn.

PAUL
First, the first quarter phase is the best phase to observe the moon.

RACHEL
Because this is when lunar craters and mountains appear their most prominent.

PAUL
That’s because we can see the very long shadows they project across the lunar surface.

RACHEL
Craters are most plentiful in the moon’s southern hemisphere.

PAUL
And mountains are most visible in the moon’s northern hemisphere.

RACHEL
The lunar mountain chains ring the perimeter of the lunar seas.

PAUL
This is where the massive impacts that created the lunar seas lifted lunar crust its highest above the surface.

RACHEL
The mountains were frozen into the surface after the impacts.

PAUL
And some of them are as tall as Mount Borah, or 12,000 feet tall.

RACHEL
Now scan the region surrounding Saturn with your binoculars.

PAUL
You can’t miss Saturn; it’s the mellow star to the lower right of the moon.

RACHEL
The region around Saturn has several hazy spots that are visible through binoculars.

PAUL
Especially when observed from locations without a local street lights.

RACHEL
These hazy spots are either glowing clouds of dust and gas…

PAUL
…or star clusters.

RACHEL
And some of the hazy spots will even contain stars you can see.   

PAUL
That’s Idaho Skies for the 17th and 18th of September.

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

For Idaho Skies this is Rachel…

PAUL
…and Paul.

RACHEL
Dark skies and bright stars.

Friday, September 14, 2018

The Moon on September 13, 2018

I used a cellphone to photograph the moon last night. The phone was held to a 40 mm eyepiece and it recorded this picture. Using a large aperture telescope makes this easier.


Monday, September 10, 2018

Idaho Skies Transcript for September 14th, 15th, and 16th

PAUL
Welcome to Idaho Skies for September 14th, 15th, and 16th. We’re your hosts, Paul…

RACHEL
…and Rachel.

PAUL
Night owls, get your binoculars out!

RACHEL
Because there’s a comet you might be able to see.

PAUL
The comet’s name is Giacobini-Zinner.

RACHEL
And it was discovered 118 years ago this December

PAUL
Comet Giacobini-Zinner orbits the sun once every 6.6 years.

RACHEL
Its path takes beyond Jupiter…

PAUL
… and just outside Earth’s orbit.

RACHEL
And this year it reaches its closest point to the sun when Earth is nearby.

PAUL
Which means it should be bright enough to see through binoculars.

RACHEL
Best of, it will appear very close to the bright star Capella on the morning of the 15th.

PAUL
So even if you can’t see the comet without optical aid, you’ll still know where to point your binoculars.

RACHEL
Now your chances of seeing the comet are better if you get out of town to make this observation.

PAUL
After arriving at a dark location, look in the low northeast for the brightest star.

RACHEL
That star is Capella, the brightest star of the pentagon-shaped Auriga.

PAUL
Point your binoculars at this star and look just to its lower left.

RACHEL
The distance between Capella and Giacobini-Zinner is 1.5 degrees.

PAUL
Or about 1/6th the distance across your binoculars’ field of view.

RACHEL
The comet will appear as a hazy disk that might appear elongated slightly to the upper right.

PAUL
That’s Idaho Skies for the 14th, 15th, and 16th of September.

RACHEL
Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.

For Idaho Skies this is Rachel…

PAUL
…and Paul.

RACHEL
Dark skies and bright stars.

Idaho Skies Transcript for September 12th and 13th

RACHEL
Welcome to Idaho Skies for September 12th and 13th. We’re your hosts, Rachel…

PAUL
…and Paul.

RACHEL
The moon keeps close company with Venus and Jupiter early this week.

PAUL
On the 12th, the moon is the triangular peak of the trio.

RACHEL
Although it’s awfully thin, this still might be a good night to look for Earthshine.

PAUL
It appears as a faint illumination on the dark portion of the moon.

RACHEL
Which becomes more apparent through binoculars.

PAUL
A telescope shows that Venus is a waning crescent.

RACHEL
In other words, it’s less than half full and gradually getting smaller.

PAUL
To see its phase, you need to aim a telescope at Venus before the sky gets dark.

RACHEL
Because after dark, the brilliance of Venus creates far too much glare for you to make out its shape.

PAUL
On the night of the 13th, stargazers will find the moon just above Jupiter and a famous double star.

RACHEL
Jupiter will be the bright star just below and left of the moon.

PAUL
Your binoculars will show you some the larger satellites of Jupiter.

RACHEL
Which look like stars in a nearly straight line with Jupiter.

PAUL
Now to the lower right of the moon, will be a second and fainter star.

RACHEL
That’s Zubenelgenubi, a double star.

PAUL
And if you aim your binoculars at this star, you’ll see it’s double.

RACHEL
Some people have sharp enough vision that they don’t need binoculars to see both stars.

PAUL
Umm, so on the 13th, stargazers have craters, satellites, and double stars to view.

RACHEL
That’s a pretty good way to spend an evening.

PAUL
That’s Idaho Skies for the 12th and 13th of September.

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

For Idaho Skies this is Rachel…

PAUL
…and Paul.

RACHEL
Dark skies and bright stars.

Idaho Skies Transcript for September 10th and 11th

PAUL
Welcome to Idaho Skies for September 10th and 11th. We’re your hosts, Paul…

RACHEL
…and Rachel.

PAUL
The moon was new on the 8th.

RACHEL
That means it will can reappear as early as the 11th.

PAUL
Quick, what else if visible in the low west these evenings?

RACHEL
Why it’s Venus, the Evening Star.

PAUL
Since Venus and the moon are both traveling along the ecliptic, the moon passes close to Venus on the 11th.

RACHEL
To see this pairing between the three-day old moon and Venus, look in the low west-southwest at around 8:45 PM.

PAUL
At first, you might only notice Venus, on account of its brightness.

RACHEL
The moon will be a very thin crescent to the right of Venus.

PAUL
Binoculars might help you see the crescent moon, but please wait until after the sun has set.

RACHEL
There’s another bright star near Venus.

PAUL
But this one is located to the upper left of Venus.

RACHEL
Care to guess what this is?

PAUL
If you said Jupiter, you’d be correct.

RACHEL
The moon is so thin that binoculars can’t show much of its surface detail.

PAUL
And Venus is still too small to show a phase.

RACHEL
But the moons of Jupiter are visible though binoculars.

PAUL
Ganymede and Io will be visible on the left.

RACHEL
And Europa and Callisto on the right.

PAUL
They’ll appear as stars forming a straight line with Jupiter.

RACHEL
That’s Idaho Skies for the 10th and 11th of September.

PAUL
Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.

For Idaho Skies this is Paul…

RACHEL
…and Rachel.

PAUL
Dark skies and bright stars.

Tuesday, September 4, 2018

Idaho Skies Transcript for September 7th, 8th, and 9th

RACHEL
Welcome to Idaho Skies for September 7th, 8th, and 9th. We’re your hosts, Rachel…

PAUL
…and Paul.

RACHEL
The moon is new on the morning of the 9th.

PAUL
That means it appears as a waning crescent on the mornings of the 7th and 8th.

RACHEL
The moon is approaching the horizon along a steep path.

PAUL
Which gives stargazers their best opportunity to see a very old moon.

RACHEL
So look in the low east at about 5:00 AM if you’re interested in this challenge.

PAUL
And remember, a pair of binoculars will help you locate the very thin crescent moon.

RACHEL
However, the moon will be so thin that binoculars won’t show much in the way of lunar details.

PAUL
Did you know that the moon’s phase is the opposite of Earth’s phase as seen from the moon?

RACHEL
Meaning that if you were standing in the dark half of the moon facing us, you’d see a nearly full Earth overhead.

PAUL
That Earth would appear as a blue and white marble four times wider and taller than the moon appears to us.

RACHEL
And about 40 times brighter.

PAUL
But unlike the stationary moon, Earth would visibly spin on its axis.

RACHEL
So in as little as an hour, observant Earth-gazers would notice a change in the planet’s appearance.

PAUL
And because of the clouds, Earth wouldn’t look the same every day.

RACHEL
According to the Apollo astronauts who walked on the moon, the continents were not readily visible to them.

PAUL
Because both continents and oceans are very dark.

RACHEL
So they mostly saw Earth’s blue atmosphere and swirling bands of white clouds. 

PAUL
That’s Idaho Skies for the 7th, 8th, and 9th of September.

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

For Idaho Skies this is Rachel…

PAUL
…and Paul.

RACHEL
Dark skies and bright stars.

Idaho Skies Transcript for September 5th and 6th

PAUL
Welcome to Idaho Skies for September 5th and 6th. We’re your hosts, Paul…

RACHEL
…and Rachel.

PAUL
Morning stargazers will find the Beehive star cluster near the moon on the 6th.

RACHEL
The Beehive is the best astronomical object in Cancer the Crab.

PAUL
And it’s one of Earth’s closest open star clusters.

RACHEL
The crab is a dim constellation and its two center stars are its most noticeable part.

PAUL
Primarily because of their proximity to each other.

RACHEL
But just barely noticeable, you’ll need to leave the city for dark country skies to see these stars.

PAUL
The northern star of this stellar pair is named Asellus Borealis.

RACHEL
And the southern is named Asellus Australis.

PAUL
Asellus by the way means donkey colt in Latin.

RACHEL
And the two stars represented two donkeys feeding at a manager between them.

PAUL
The manager in this case, was a small nebulous patch that the ancients saw between the two stars.

RACHEL
Galileo was the first to turn an astronomical telescope to this hazy spot in 1609.

PAUL
And he was surprised to discover that it consisted on some 40 stars.

RACHEL
To find the Beehive star cluster yourself, aim your binoculars at the moon on the morning of the 6th.

PAUL
Which will be a very thin crescent in the low east at 5:00 AM.

RACHEL
Then shift your binoculars towards the lower left of the moon until it just disappears from the binocular view.

PAUL
The Beehive will pop into view in the 7 o’clock position.

RACHEL
Be sure to count the number of stars you can see.

PAUL
Can you see 40 stars like Galileo?

RACHEL
That’s Idaho Skies for the 5th and 6th of September.

PAUL
Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.

For Idaho Skies this is Paul…

RACHEL
…and Rachel.

PAUL
Dark skies and bright stars.

Idaho Skies Transcript for September 3rd and 4th

RACHEL
Welcome to Idaho Skies for September 3rd and 4th. We’re your hosts, Rachel…

PAUL
…and Paul.

RACHEL
The star cluster M-35 is only 5 degrees from the moon on the morning of the 4th.

PAUL
That means it’s within binocular view of the moon.

RACHEL
M-35 is not a very bright cluster, so the moon’s close proximity will make it much easier to locate than normal.

PAUL
And it’s visible in binoculars as long as you get out from under the lights.

RACHEL
Around 5:00 AM will be a good time to go looking for this star cluster.

PAUL
So find the thin waning crescent moon in the east in Gemini the Twins.

RACHEL
Then point your binoculars at the moon and place it on the right edge of your view.

PAUL
The M-35 star cluster will appear between the center and left edge of your view.

RACHEL
This is a galactic star cluster.

PAUL
Or one that’s irregularly-shaped and not strongly concentrated towards the center.

RACHEL
Galactic star clusters contain fewer stars than spherical globular star clusters.

PAUL
And galactic star clusters are younger to boot.

RACHEL
Our sun was most likely born in a galactic star cluster like M-35 along with possibly hundreds of siblings.

PAUL
Over millions of years, the stars left their nest to start their own journeys through the galaxy.

RACHEL
Today, some 4.5 billion years after their birth, these stars are scattered across the galaxy.

PAUL
Meaning we can’t currently see any of the sun’s siblings.

RACHEL
Besides, the more massive stars of the sun’s birth cluster have died by now.

PAUL
Leaving only stars with masses like the sun and smaller.

RACHEL
That’s Idaho Skies for the 3rd and 4th of September.

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.