Tuesday, September 19

 

Uranus reaches opposition one month from today, but it already has become a tempting evening target. The ice giant world rises before 9 p.m. local daylight time and climbs some 30° above the eastern horizon by 11 p.m. The magnitude 5.7 planet lies in Pisces, 1.1° northwest of magnitude 4.3 Omicron (o) Piscium. Although Uranus glows brightly enough to see with the naked eye under a dark sky, binoculars make the task much easier. A telescope reveals the planet’s blue-green disk, which spans 3.7".

 

Wednesday, September 20

New Moon occurs at 1:30 a.m. EDT. At its new phase, the Moon crosses the sky with the Sun and so remains hidden in our star’s glare.

 

Thursday, September 21

Although you can’t see the Moon around its New phase, its absence from the morning sky these next two weeks provides observers with an excellent opportunity to view the zodiacal light. From the Northern Hemisphere, early autumn is the best time for viewing this elusive glow before sunrise. It appears slightly fainter than the Milky Way, so you’ll need a clear moonless sky and an observing site located far from the city. Look for a cone-shaped glow that points nearly straight up from the eastern horizon shortly before morning twilight begins (around 5 a.m. local daylight time at mid-northern latitudes). The Moon remains out of the morning sky until October 4, when the waxing gibbous world returns and overwhelms the much fainter zodiacal light.

 

Friday, September 22

With the days growing shorter and kids back in school, it shouldn’t be surprising that summer’s reign is just about over. The warmest season comes to an official close at 4:02 p.m. EDT, when Earth reaches the autumnal equinox. This marks the moment when the Sun crosses the celestial equator traveling south. Our star rises due east and sets due west today. If the Sun were a point of light and Earth had no atmosphere, everyone would get 12 hours of sunlight and 12 hours of darkness. But the air and finite size of our star make today a few minutes longer than 12 hours.

 

The Moon appears as a waxing crescent low in the west-southwest during evening twilight. Tonight, you can use it as a guide for finding Jupiter. Although the gas giant planet has been a conspicuous evening object for the past several months, it’s now nearing the end of its reign. The giant planet lies 8° to the lower right of the Moon but just 6° above the horizon a half-hour after sundown. Still, at magnitude –1.7, Jupiter shines brightly enough to appear prominent against the twilight glow.

 

Saturday, September 23

The variable star Algol in Perseus reaches minimum brightness at 2:56 a.m. EDT. Observers on the East Coast who start watching around midevening on the 22nd can see the star’s brightness diminish by 70 percent over the course of about five hours. Those in western North America will see Algol brighten noticeably from late evening until dawn starts to paint the sky, when the star passes nearly overhead. This eclipsing binary system runs through a cycle from minimum (magnitude 3.4) to maximum (magnitude 2.1) and back every 2.87 days.

 

Sunday, September 24

Although autumn arrived with the equinox two days ago, the Summer Triangle remains prominent in the evening sky. Look high in the west after darkness falls and your eyes will fall on the brilliant star Vega in the constellation Lyra the Harp. At magnitude 0.0, Vega is the brightest member of the Triangle. The second-brightest star, magnitude 0.8 Altair in Aquila the Eagle, lies some 35° southeast of Vega. The asterism’s dimmest member, magnitude 1.3 Deneb in Cygnus the Swan, stands about 25° east-northeast of Vega. For observers at mid-northern latitudes, Deneb passes through the zenith around 9:30 p.m. local daylight time, more than an hour after the last vestiges of twilight disappear.

Okay, okay --- I'm still not over the eclipse. There is nothing quite like seeing the sun's magnificent corona during a total eclipse. I know that August 21 is a day that I will never forget. It is hard to adequately describe seeing that majestic crown of hot gases first hand. No photograph can do it justice. But this one is pretty nice.

 

The human eye can adapt to see coronal features and extent that average cameras usually cannot. Welcome, however, to the digital age. The picture below is a combination of forty exposures from one thousandth of a second to two seconds that, together, were digitally combined and processed to highlight faint features of the total solar eclipse that occurred on August 21. Clearly visible are intricate layers and glowing caustics of an ever changing mixture of hot gas and magnetic fields in the Sun's corona. Looping prominences appear bright pink just past the Sun's limb. Faint details on the night side of the New Moon can even be made out, illuminated by sunlight reflected from the dayside of the Full Earth.

 

SF, I just wanted to report that I did shed some tears Friday morning as Cassini ended her mission.

 

However, death, even of a spacecraft, is inevitable. Cassini is now PART of the planet that it revealed so much about. It's really a very fitting end to a spectacular life.

 

This is the type of thing that makes me wonder if some of the elements on Earth and in its atmosphere arrived this way.

 

If the theory goes that we are not alone in the universe, it should follow that we never were.

 

Going a step further, in one of my completely unfounded and probably easily disproved theories, I would argue life started on Mercury, and after evolving to the point the planet was uninhabitable, moved along to Venus- lather, rinse, repeat, and here we are in phase three on this fun little rock called Earth, with a very little(relatively speaking) time remaining until Mars is the only way to save humanity.

This is the type of thing that makes me wonder if some of the elements on Earth and in its atmosphere arrived this way.

 

If the theory goes that we are not alone in the universe, it should follow that we never were.

 

Going a step further, in one of my completely unfounded and probably easily disproved theories, I would argue life started on Mercury, and after evolving to the point the planet was uninhabitable, moved along to Venus- lather, rinse, repeat, and here we are in phase three on this fun little rock called Earth, with a very little(relatively speaking) time remaining until Mars is the only way to save humanity.

 

Interesting post. Glad to have you on board. Hope to hear more of your thoughts.

Dawn Breaking over Hungary...

 

I mentioned the other day about the morning alignment of the Moon, three planets, and Regulus in the pre-dawn sky. Bluegrasscard posted some pics of what he observed that morning. Here is a lovely picture of the morning sky over Hungary on the 18th.

 

In this twilight skyscape, Mercury and Mars still shine close to the eastern horizon, soon to disappear in the glare of the Sun. Regulus, alpha star of the constellation Leo, is the bright point next to a waning crescent Moon, with brilliant Venus near the top of the frame. The beautiful morning conjunction of Moon, planets, and bright star could generally be followed by early morning risers all around planet Earth. But remarkably, the Moon also occulted, or passed directly in front of, Regulus and each of the three planets within 24 hours, all on September 18 . It won't be until 2036 when the Moon will again occult three planets in less than one day.

 

Dawn Breaking over Hungary...

 

I mentioned the other day about the morning alignment of the Moon, three planets, and Regulus in the pre-dawn sky. Bluegrasscard posted some pics of what he observed that morning. Here is a lovely picture of the morning sky over Hungary on the 18th.

 

In this twilight skyscape, Mercury and Mars still shine close to the eastern horizon, soon to disappear in the glare of the Sun. Regulus, alpha star of the constellation Leo, is the bright point next to a waning crescent Moon, with brilliant Venus near the top of the frame. The beautiful morning conjunction of Moon, planets, and bright star could generally be followed by early morning risers all around planet Earth. But remarkably, the Moon also occulted, or passed directly in front of, Regulus and each of the three planets within 24 hours, all on September 18 . It won't be until 2036 when the Moon will again occult three planets in less than one day.

 

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Don't forget to mention the Earthshine in this APOD photo.

Don't forget to mention the Earthshine in this APOD photo.

 

Yes, thank you. Earthshine is occurring because sunlight is reflecting off the Earth's surface and illuminating the unlit portion of the waxing crescent moon. This is a dull, or pale, glow of light compared to the lit portion of the moon since it is twice-reflected light, first off the Earth's surface, then off the moon's surface.

 

Does anyone know who was the first person to explain this Earthshine phenomenon? (It wasn't me or TB&G) Hint: He was pretty good at using light and color to his advantage.

Yes, thank you. Earthshine is occurring because sunlight is reflecting off the Earth's surface and illuminating the unlit portion of the waxing crescent moon. This is a dull, or pale, glow of light compared to the lit portion of the moon since it is twice-reflected light, first off the Earth's surface, then off the moon's surface.

 

Does anyone know who was the first person to explain this Earthshine phenomenon? (It wasn't me or TB&G) Hint: He was pretty good at using light and color to his advantage.

 

 

Go right ahead, J-Dad.

 

 

Good gracious!!!

 

Yessir indeed.

 

Leonardo Da Vinci was first to explain Earthshine. In fact, I think some refer to it as Da Vinci glow.

Who wants to take a guess at what this object is? Hint: It's the largest in a certain category.

 

At first glance it kinda looks like our moon, but it's not. I'm not sure exactly what it is.

At first glance it kinda looks like our moon, but it's not. I'm not sure exactly what it is.

 

It's somebody's moon.

 

Hint at the lower right of the picture.

At first glance it kinda looks like our moon, but it's not. I'm not sure exactly what it is.

 

Btw. Love having you talk astronomy with us.