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Posts Tagged ‘Sunset’

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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Last night’s sunset was beautiful, but didn’t promise clear skies

August 7, 2016 Comments off
Sunset

Just after sunset from a hill top near Suttons Bay, MI. Credit Bob Moler.

The view is across most of the Leelanau Peninsula, the Manitou Passage, and North Manitou Island at the sunlit bottoms of the clouds just after sunset.

The event was the annual Grand Traverse Astronomical Society picnic and star party.  Most of the evening was consumed by fleeting glimpses of Saturn and deep sky objects through the holes in the clouds by members telescopes and the society’s 25 inch “Dobinator” which was run by a crew headed by telescope “wrangler” Don Flegel.  Before sunset the Sun provided some glorious prominences for us.

06/15/2015 – Ephemeris – The earliest sunrise

June 15, 2015 Comments off

Ephemeris for Monday, June 15th.  Today the Sun will be up for 15 hours and 33 minutes, setting at 9:30.   The Moon, 1 day before new, will rise at 6:19 tomorrow morning.  Tomorrow the Sun will rise at 5:56.

This is the day of the earliest sunrise.  We are still six days from the summer solstice, that day the Sun stays up the longest. And 11 days from the latest sunset.  I could be off a day since I don’t calculate sunrise and sunset times to the second.  I use the standard formula for these computations, which, among other things assumes that the horizon is the sea horizon.  If you’re standing on the bluffs overlooking Lake Michigan, sunset would be slightly later than one seen down on the shore, and for the Sleeping Bear Dunes or Empire Bluff, your sunset would be 2 minutes later that Traverse City or Interlochen anyway because that’s west of them.  At the latitude of 45 degrees the rise and set times are 1 minute later for each 12 and a half miles west you are.

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

Addendum

The discussion turned from sunrises to sunsets.  Well, sunsets are a bigger deal this side of the state.  I suppose that if I lived in Alpena or Rogers City, I’d be more interested in sunrises.  The timing difference for the rising and setting of celestial objects depends on the longitude one is versus the longitude of the position for which it is calculated, as long as one stays at roughly the same latitude.  The times for this program are for a position roughly half way between Interlochen and Traverse City.  Full disclosure:  It’s the Moler homestead.  Back, when I started this program in 1975, it was an era I call BC.  Before Computers, well before personal computers.  I used the rising and setting tables from the Royal Canadian Astronomical Society’s Observer’s Handbook for the year in question, adjusting for longitude.  I climbed op on my rooftop to verify the times several times a year.  That was back when my house wasn’t surrounded by trees.

In the sky east or west, what we call longitude on the Earth is marked not in degrees, but in hours, minutes and seconds.  Since 360 degrees or Earth’s rotation equals 24 hours, one hour equals 15 degrees, and each degree equals 4 minutes.  In Traverse City, near 45 degrees north latitude,  The longitude lines are closer than at the equator.  They are 71% that of the equatorial separation.  Working it out, each minute of rotation equates to 12.31 miles.  The 12 1/2 miles is close enough for radio, and besides I had calculated it a looooong time ago and was pulling it off the top of my head.  I recalculated it just now.

Any change time in the rising and setting of objects for persons north or south of the standard position depends on the object’s declination (latitude in the sky) north of south of the celestial equator, so the calculation isn’t as simple.

05/20/2014 – Ephemeris – Special doings at the Sleeping Bear National Lakeshore Friday Night

May 20, 2014 Comments off

Ephemeris for Tuesday, May 20th.  Today the sun will be up for 14 hours and 59 minutes, setting at 9:09.   The moon, 1 day before last quarter, will rise at 2:09 tomorrow morning.  Tomorrow the sun will rise at 6:08.

This Friday evening Dr. Tyler Nordgren, astronomer, artist and dark sky advocate will give a presentation at the Sleeping Bear Dunes National Lakeshore Philip A. Hart Visitor Center in Empire at 7 p.m. Afterward he will be signing copies of his beautiful new poster See the Stars from Sleeping Bear Dunes National Lakeshore featuring the Great and Little Bear constellations and the bluffs of the Sleeping Bear Dunes and the Manitou Islands.  After that, weather permitting see the sunset from many of the parks locations, then, for the hardy, settle down for an all night vigil for a possible meteor storm with the Grand Traverse Astronomical Society at the Dune Climb (The bottom, not the top, though you can climb up there for an all-sky view.).

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

Addendum

Poster

See the Stars from Sleeping Bear Dunes National Lakeshore Poster by Tyler Nordgren.

06/26/2013 – Ephemeris – Latest sunset and the Summer Triangle

June 27, 2013 Comments off

Ephemeris for Thursday, June 27th.  Today the sun will be up for 15 hours and 32 minutes, setting at 9:31.   The moon, 3 days before last quarter, will rise at 12:14 tomorrow morning.  Tomorrow the sun will rise at 5:59.

Last night we had the latest sunset of the year.  The sun is really beginning to head south.  Other than the sunrise and sunset numbers, we’ll begin to notice it for real in a few weeks.  At first that realization strikes me a sad note that summer is beginning to end.  However the astronomer in me realizes that means more night-time hours, and that the summer Milky Way is coming.  Of the three bright stars of the Summer Triangle overhead and in the east, two of its stars are in the milky band.  They are Deneb to the north and Altair to the south.  Vega, closest to the zenith is not in the band.  Actually all the stars we see with the naked eye or small telescopes belong to the Milky Way galaxy.

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

Addendum

The Summer Triangle July 5, 2012 at 11 p.m. Created using Stellaruim and The Gimp.

The Summer Triangle at 11 p.m. Created using Stellaruim and The Gimp.