Transcript fior September 29th to October 5th

RACHEL
Welcome to Idaho Skies for the first week of October. We’re your hosts, Rachel…

PAUL
… and Paul.

RACHEL
The very thin crescent moon is located between Regulus, the brightest star of Leo the Lion, and Mars on the 1st.

PAUL
You’ll need to go outside at 6:00 AM to see this alignment.

RACHEL
Regulus, also known as Alpha Leonis to astronomers, is 77 light years away.

PAUL
So if you know someone who is 77 years old this year, Regulus is their birthday star.

RACHEL
Mars is too small and distant to show any detail in binoculars.

PAUL
And the moon will be so thin that binoculars won’t make out much detail on its surface.

RACHEL
Speaking of the moon, did you know the far side of the moon remained a mystery until 54 years ago this month?

PAUL
The Soviet Union placed the spacecraft Luna 3 into a very elliptical orbit.

RACHEL
At its farthest point from Earth, it passed behind the moon.

PAUL
As it passed  the moon on October 3, 1959, the 950 pound, solar-powered Luna 3 snapped several poor quality images of the moon’s far side.

RACHEL
This was back in the days of film, so the Luna 3 had to develop the negatives itself.

PAUL
As it passed close to Earth again, Luna 3 scanned the images and transmitted them as a fax.

RACHEL
Remember that the moon has a far side, but not a dark side.

PAUL
That’s right; the far side gets daylight for two weeks per month, so it’s no darker than the near side that we can see.

RACHEL
The reason the moon has a far side is that it is tidally locked.

PAUL
This happens to all small astronomical bodies that are orbiting close to massive astronomical bodies.

RACHEL
It’s happening now to Mercury because of its small distance from the sun.

PAUL
The hot Jupiter exoplanets that astronomers have discovered around other stars are likely tidally locked also.

RACHEL
The moon is new on the 4th.

PAUL
This means the first week of October is a great time for observing faint fuzzy objects through your binoculars or telescope.

RACHEL
Unfortunately, it also means that the moon will be near full at the peak of the Orionid meteor shower.

PAUL
In place of observing meteors, try observing the Zodiacal Light this month.

RACHEL
It appears as a faint glowing pillar of light in the east at least two hours before sunrise.


PAUL
Unlike the dawn, the Zodiacal Light forms a tall triangular-shaped pillar that tilts slightly towards the south.

RACHEL
It’s the reflection of sunlight off of comet dust orbiting the sun.

PAUL
You don’t have to be in a hurry to see the Zodiacal Light; you have until the 17th to see it.

RACHEL
After then, the moon’s light will brighten the sky and interfere.

PAUL
That’s Idaho Skies for the first week of October. Next week the moon passes through the best part of the Milky Way, so get your binoculars ready.

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

For Idaho Skies this is Rachel…

PAUL
and Paul.

RACHEL
Dark skies and bright stars.

This month look for the star Deneb, the brightest star of the constellation of Cygnus the Swan. The word Deneb is Arabic for tail, referring to the fact that the star represents the swan’s tail. Deneb is the 19th brightest star in the sky. It, along with the stars Vega and Altair form the Summer Triangle. The Summer Triangle is an asterism and not a constellation. The Summer Triangle passes directly overhead at 9:00 PM in early September.

Deneb is somewhere between 1,600 and 2,600 light years away. This makes Deneb the most distant star visible without a telescope. The reason that we can see it from so far away is that it is a massive star. It has 20 times the mass of the Sun and a diameter 200 times greater than our Sun’s diameter. If Deneb were to replace our Sun, it would fill the orbit of Earth. Deneb’s large mass makes it 250,000 times brighter than the Sun. Deneb has a surface temperature of 16,000 degrees Fahrenheit, or white hot. For Earth to maintain a mild climate while in orbit around Deneb, Earth would have to orbit Deneb at a distance ten times greater than the distance between Pluto and the Sun. The supergiant Deneb is so hot that it is blowing material off of its surface at a rate a thousand times faster than the Sun. This large mass loss is not sufficient, however, to reduce Deneb’s mass down to safe levels before its too late. Within a few million years, Deneb will end its life in a supernova explosion.     

Deneb appears directly overhead at 9:30 PM in early September and at 8:30 PM by the end of the month. Look for Deneb as the faintest and most northeast member of the Summer Triangle.