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Posts Tagged ‘Mare Crisium’

09/13/2018 – Ephemeris – The Man in the Moon’s eye

September 13, 2018 Comments off

Ephemeris for Thursday, September 13th. The Sun will rise at 7:19. It’ll be up for 12 hours and 37 minutes, setting at 7:57. The Moon, 3 days before first quarter, will set at 10:27 this evening.

The Moon tonight is a 4 day old moon, and appears near the planet Jupiter. Day one is its first appearance in the evening after disappearing from the morning sky. The ancients called it the new moon, but astronomers treat the conjunction of the Moon and the Sun as the new moon. In this program I note the days before or after the nearest quarter phase, as a better representation of the actual appearance of the Moon’s phase. The Moon will be a beautiful crescent tonight. Binoculars will reveal a dark area just above the fattest part of the crescent. It serves as one of the Man in the Moon’s eyes. Its official name is Mare Crisium, or Sea of Crises. Most of the Moon’s seas are connected, or appear to be. This one is definitely not.

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

Addendum

The 4 day old Moon

The 4 day old Moon showing Mare Crisium, the Sea of Crises. 9 p.m. September 13, 2018. Created using Virtual Moon Atlas.

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06/07/2016 – Ephemeris – The Moon reappears in the evening sky

June 7, 2016 Comments off

Ephemeris for Tuesday, June 7th.  Today the Sun will be up for 15 hours and 28 minutes, setting at 9:26, and it will rise tomorrow at 5:57.  The Moon, 3 days past new, will set at 11:41 this evening.

The  Moon tonight is a thin crescent with the night side faintly illuminated by the Earth.  The effect is called earthshine.   The small dark sea of Crises, or Mare Crisium, near the right edge of the moon will be cut in half by the moon’s terminator, its sunrise line.  Venus, which passed behind the Sun yesterday, though now an official evening planet probably won’t become easily visible till near the end of summer.  The evening sky now through mid July is a time where it seems that twilight never ends.  However for almost the next two weeks, we have the bright planets Jupiter, Mars and Saturn plus the Moon to help us forget the seemingly forever twilight blues.  After that we’ll have just the planets. Not a bad deal.

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

Addendum

The Moon showing earthshine

The Moon showing earthshine at 10:30 p.m. June 7, 2016. Created using Virtual Moon Atlas.

Note:  The image, from Virtual Moon Atlas, has been rotated to show the approximate appearance in the sky of the Moon low in the southwest.  I didn’t attempt to add the sky brightness and color.

05/10/2016 – Ephemeris – The lunar Sea of Crises

May 10, 2016 Comments off

Ephemeris for Tuesday, May 10th.  The Sun rises at 6:19.  It’ll be up for 14 hours and 39 minutes, setting at 8:59.  The Moon, 3 days before first quarter, will set at 1:04 tomorrow morning.

Tonight the Moon shows one remarkable sea:  Mare Crisium or the Sea of Crises.  It is a large gray basin.  The largest feature visible in binoculars.  Because it’s near the Moon’s limb or edge it is foreshortened into an ellipse, with the long axis running north and south.  In actuality it is elliptical with the long axis east and west.  It looks funny on a geologic map of the whole moon or a Moon globe.  Its dimensions are 345 by 375 miles (570 by 620km).  It’s really a crater as are all seas whose impact asteroid reached down to the Moon’s magma and caused lava to well up to produce the flat floor.  When the sunlight is low as it is now wrinkle ridges will appear showing where successive lava flows have stopped and solidified.

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

Addendum

Moon proper orientation

The Moon’s approximate orientation and phase at May 10, 2016. Created using Stellarium.

04/11/2016 – Ephemeris – The margins of the Moon

April 11, 2016 Comments off

Ephemeris for Monday, April 11th.  The Sun will rise at 7:04.  It’ll be up for 13 hours and 18 minutes, setting at 8:23.   The Moon, 2 days before first quarter, will set at 1:28 tomorrow morning.

Lets check out the Moon tonight.  The Moon’s terminator, now the sunrise line traversing the Moon is beginning to uncover the dark Mare Tranquillitatis or Sea if Tranquility on the equator of the Moon.  The small round prominent sea on the right side of the Moon is Mare Crisium, or Sea of Crises.  At the limb beyond Crisium is Mare Marginis or sea at the Margin, and below it also at the edge is Mare Smythii, or Smith’s Sea, named after William Henry Smith a 19th century British astronomer.  These last two seas are only visible when the Moon appears to rock to the left and reveals them.  This is called libration caused by the fact the Moon rotates at a constant rate and it orbits the Earth in an ellipse, changing it’s speed.

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

Addendum

Moon April11, 2016

Map of the Moon for April 11, 2016. The arrow shows the point of maximum libration for that date. Created using Virtual Moon Atlas.

Apollo 8 image annotated

Photo of the receding Moon taken by the Crew of Apollo 8 as they started to head home showing the near side on the left and the far side on the right. I’ve annotated the seas which I’ve described above. Credit NASA.

02/06/2014 – Ephemeris – The moon tonight and libration

February 6, 2014 Comments off

Ephemeris for Thursday, February 6th.  The sun will rise at 7:55.  It’ll be up for 10 hours and 3 minutes, setting at 5:58.   The Moon, at first quarter today, will set at 2:11 tomorrow morning.

The Moon, being at first quarter today, has the terminator or sunrise line cut the Moon in half tonight.  In binoculars and telescopes the best detail is seen near the terminator where the shadows are longest.  The farther one wanders with a telescope the flatter the terrain appears.  There’s another effect that can be seen.  It’s called libration where the Moon appears to slowly wobble during the month.  This is mostly caused by the Moon’s very steady rotation countered by the fact that the Moon’s orbit is elliptical and gets ahead or behind the rotation.  At the upper right of the Moon is the small Sea of Crises.  That has rotated forward a bit revealing yet another sea at the edge of the Moon, Mare Marginis, the Margin or Border Sea.

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

Addendum

The Moon

The Moon highlighting the Ephemeris topics at 9 p.m. on February 6, 2014. Created using Virtual Moon Atlas.

The Moon

The Moon highlighting the Ephemeris topics at 9 p.m. on February 6, 2014. Created using Virtual Moon Atlas.

01/17/2014 – Ephemeris – The Moon tonight

January 17, 2014 1 comment

Ephemeris for Friday, January 17th.  The sun will rise at 8:14.  It’ll be up for 9 hours and 16 minutes, setting at 5:30.   The moon, 2 days past full, will rise at 7:23 this evening.  |  Let’s take a look at the moon as it’s still dominates the evening sky.  The terminator, now that it’s after full moon is the sunset line.  It is just starting to encroach on the small distinctive sea at the moon’s upper right edge called the Sea of Crises or Mare Crisium.  Where is is situated on the edge of the spherical moon it appears to be elongated north to south.  However if you saw it from overhead it would actually be elongated somewhat east to west.  On the terminator at the moon’s equator is a large crater called Langrenus with a central peak on the edge of the Sea of Fertility or Mare Fecunditatis, that should be an easy binocular and a great telescopic crater some 80 miles in diameter.  The smallest ting you can see on the moon in a small telescope is 2 miles in diameter.

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

Addendum

Moon

The Moon at 9 p.m., January 17, 2014. Created using Virtual Moon Atlas.

Moon

Mare Crisium as seen from overhead at 9 p.m., January 17, 2014. Created using Virtual Moon Atlas.

This last image cannot be seen without a spacecraft.  The image was created using data from the Clementine spacecraft.