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Archive for the ‘Atmospheric Phenomena’ Category

06/05/2018 – Ephemeris – Green flash

June 5, 2018 Comments off

Ephemeris for Tuesday, June 5th. Today the Sun will be up for 15 hours and 25 minutes, setting at 9:24, and it will rise tomorrow at 5:58. The Moon, 1 day before last quarter, will rise at 2:16 tomorrow morning.

Now that it’s June and the season of summer is only two weeks away, thoughts run to heading out to the beach. One of the great pleasures of heading out to a Lake Michigan beach is seeing the sunset. And if the Sun sets on the cloudless horizon, a rare treat is to see the green flash. I’ve heard about it since my youth, but have seen it only once. I’ve seen the sunset many, though not a huge number of, times. The time I did, I was purposely looking for it. The green flash is when as the last part of the upper limb of the Sun disappears it suddenly turns green for a second, then it’s gone. So it’s easy to miss. The flash isn’t really brighter, but the top edge turns suddenly from reddish-orange to green as it disappears.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Green flash in stages

The green flash recorded by Brocken Inaglory in January 2006 from Santa Cruz, CA. GNU Free Documentation License from the Green Flash Wikipedia page, which has more examples.

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05/28/2018 – Ephemeris – NASA’s Juno spacecraft takes deep dives at Jupiter

May 28, 2018 Comments off

Ephemeris for Memorial Day, Monday, May 28th. Today the Sun will be up for 15 hours and 15 minutes, setting at 9:17, and it will rise tomorrow at 6:02. The Moon, 1 day before full, will set at 6:24 tomorrow morning.

NASA’s Juno spacecraft has made 11 close passes of Jupiter since being inserted into Jovian orbit in July 2016. It has a highly elliptical orbit. It comes in over the north pole, passes only 2,000 miles over the cloud tops at the equator and heads out over the south pole, avoiding the most intense parts of Jupiter’s radiation belts. The high latitude and polar clouds appear more chaotic than expected. We can’t see these very well from the Earth. The magnetic field is much stronger and lumpier than thought before. A very much improved and complex picture of our largest planet is emerging, as we expected. The mission isn’t over and years of analysis are ahead to begin to more fully understand the solar system’s greatest planet.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addenda

Chaotic storms at Jovian high latitudes

Chaotic storms at Jovian high latitudes. Credit NASA/JUNO

North Polar Cyclones

Jupiter’s North Pole in the infrared. 8 cyclones surrounding a 9th at the pole. Credit: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM

South Polar Cyclones

Jupiter’s South Pole in the infrared. 5 cyclones surrounding a 6th at the pole. Credit: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM

Alan Bean

Astronaut Alan Bean, 4th person to walk on the Moon with Apollo 12 passed away this weekend.  He also commanded the second Skylab mission and retired to become an artist, a painter of his adventures on the Moon and in space.  Of the twelve men who walked on the Moon, only four survive.

08/27/2015 – Ephemeris – Thunderstorms can produce sprites pointing upward

August 27, 2015 2 comments

Ephemeris for Thursday, August 27th.  The Sun will rise at 6:59.  It’ll be up for 13 hours and 29 minutes, setting at 8:28.   The Moon, 2 days before full, will set at 5:32 tomorrow morning.

Thunderstorms are dangerous, as we experienced with the destruction our area experienced with the August 2nd storm.  But beside the lightning, wind, rain, hail and tornadoes thunderstorms also can produce sprites which appear to be electrical discharges extending above the tops of the clouds up to 56 miles.  While reported as far back as 1886, they were finally photographed in 1989.  They have been photographed many times since from the ground, aircraft and the International Space Station.  The images of them that I’ve seen appear to be red in color.  However there’s also Blue Jets, Blue Starters, Gigantic Jets and ELVES.  Wikipedia describes their appearance, but there appears to be little understanding of them.

Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Sprites

Photograph of Sprites over a Thunderstorm from the International Space Station. NASA/ISS edited by Bob Moler.

06/02/2015 – Ephemeris – Bright clouds that appear near the end of twilight

June 2, 2015 Comments off

Ephemeris for Tuesday, June 2nd.  Today the Sun will be up for 15 hours and 21 minutes, setting at 9:21.   The Moon, at full today, will rise at 9:18 this evening and tomorrow the Sun will rise at 5:59.

This time of year one can see, on rare occasions, some ghostly clouds called noctilucent clouds.  Noctilucent means night shining.  These are silvery clouds that can be seen near the end of twilight.  We’re a bit south of the prime latitudes to see them from 50 to 70 degrees both north and south of the equator.  I’ve seen them but a few times.  They move rather rapidly, even though they’re at an altitude of around 50 miles.  The clouds appear to be made of ice crystals that possibly form around meteoritic dust. Their appearance cannot be predicted, but be aware that they may appear near the end of twilight and they are white, move rapidly, and are not the twilit clouds lower down.  These clouds are most numerous during July and August.  They seem to be showing up early this year.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.

Addendum

Noctilucent Clouds

Noctilucent clouds, Kuresoo bog, Soomaa National Park, Estonia. July 26, 2009 by Martin Koitmäe. From Wikimedia Commons.

AIM Noctilucent Clouds from July 6, 2014

NASA Aeronomy of Ice in the Mesosphere (AIM) satellite data of Earth’s north polar region from July 6, 2014. Credit LASP/University of Colorado.

06/25/2013 – Ephemeris – Noctilucent Clouds

June 25, 2013 Comments off

Ephemeris for Tuesday, June 25th.  Today the sun will be up for 15 hours and 33 minutes, setting at 9:31.   The moon, 2 days past full, will rise at 11:07 this evening.  Tomorrow the sun will rise at 5:58.

This time of year one can see, on rare occasions, some ghostly clouds called noctilucent clouds.  Noctilucent means night shining.  These are silvery clouds that can be seen near the end of twilight.  We’re a bit south of the prime latitudes to see them from 50 to 70 degrees both north and south of the equator.  I’ve seen them but a few times.  They move rather rapidly, even though they’re at an altitude of around 50 miles.  The clouds appear to be made of ice crystals that possibly form around meteoritic dust or volcanic ash.  Their appearance cannot be predicted, but be aware that they may appear near the end of twilight and they are white, move rapidly, and are not the twilit clouds lower down.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.

Addendum

Noctilucent Clouds

Noctilucent clouds, Kuresoo bog, Soomaa National Park, Estonia. July 26, 2009 by Martin Koitmäe. From Wikimedia Commons.