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10/22/2015 – Ephemeris – My favorite lunar feature
Ephemeris for Thursday, October 22nd. The Sun will rise at 8:07. It’ll be up for 10 hours and 39 minutes, setting at 6:46. The Moon, 2 days past first quarter, will set at 3:10 tomorrow morning.
The Moon tonight is revealing my favorite feature, Sinus Iridium or Bay of Rainbows. Unfortunately features on the Moon are not that colorful. The Bay of Rainbows is surrounded on three sides by a semicircular mountain range called the Jura Mountains which is actually a broken down crater wall. The Bay is a bay in Mare Imbrium, the Sea of Showers. It is the nomenclature of land forms on planets and moons that still have Latin names in astronomy. That and constellations. Of course the Bay of Rainbows and the Sea of Showers aren’t real bodies of water. These were the product of the imaginations of astronomers looking through their primitive telescopes, at a completely alien landscape.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Moon tonight with Sinus Iridium peeking out into the morning sunlight on the Moon, 9 p.m. October 2015. Created using Virtual Moon Atlas.
Sinus Iridium photographed by the Lunar Reconnaissance Orbiter as texture mapped on the globe of the Virtual Moon Atlas.
08/24/2015 – Ephemeris – The Bay of Rainbows
Ephemeris for Monday, August 24th. The Sun rises at 6:55. It’ll be up for 13 hours and 38 minutes, setting at 8:34. The Moon, 2 days past first quarter, will set at 2:17 tomorrow morning.
One of my favorite lunar formations is creeping into sunlight on the Moon this evening. Look to the upper left edge of the moon tonight. The large sea or dark area of the Moon, the Man in the Moon’s right eye as he’s looking at us is Mare Imbrium, the Sea of Showers. At the top left edge of that sea is a large notch. And keeping with of seas these of the first telescopic astronomers its name is Sinus Iridium, or Bay of Rainbows, a colorful name for something as colorless as the rest of the Moon. The terminator which is the sunrise line will be cutting across that bay, illuminating the semicircular mountain ring that surrounds it before all of the floor is illuminated. It can be seen in binoculars or a small telescope.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Moon at 10 p.m. August 24, 2015 showing the location of Sinus Iridium. Created using Virtual Moon Atlas.
The moon at 10 p.m. August 24, 2015 with Sinus Iridium extending into the lunar night. Created using Virtual Moon Atlas.
This is for 2 hr UT August 25, 2015.
03/11/2014 – Ephemeris – Observing the moon tonight: Bay of Rainbows and more
Ephemeris for Tuesday, March 11th. The sun will rise at 8:02. It’ll be up for 11 hours and 41 minutes, setting at 7:43. The moon, 4 days past first quarter, will set at 5:39 tomorrow morning.
The moon tonight is a pretty fat gibbous shape, with the sunrise line or terminator revealing the Bay of Rainbows, Sinus Iridium, that large half crater at the moon’s upper left edge, and the edge of the Sea of Showers, Mare Imbrium. In the figure of the man in the moon Imbrium is his big eye, kind of like the cartoon “Bill the Cat”. To the right of it, looking like a hole in a mountain chain, is Plato, whose dark floor is unmistakable even at full moon, when shadows are absent. The crater Copernicus is now beginning to be washed out as the morning shadows shrink. To the left of Copernicus, just catching the sun’s rays on the terminator, is the smaller crater Kepler. When the moon is full Kepler will show a fine ray system.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Moon at 10 p.m. on March 11, 2014. Created using Virtual Moon Atlas.
Note for those not in the Eastern Daylight time zone. 10 p.m. is 2 hours March 12, 2014. If viewing before that time the terminator will be shifted to the right. After the terminator will be shifted to the left.
06/18/2013 – Ephemeris – The moon’s most striking feature, the Jura Mountains and the Bay of Rainbows
Ephemeris for Tuesday, June 18th. Today the sun will be up for 15 hours and 33 minutes, setting at 9:30. The moon, 2 days past first quarter, will set at 2:48 tomorrow morning. Tomorrow the sun will rise at 5:56.
On the moon tonight the gibbous phase and the terminator on the left side of the moon is revealing a large semi circular mountain range called the Jura Mountains that encloses a flat lava plain that looks like a bay in the margin of the Sea of Showers or Mare Imbrium. The bay is Sinus Iridium, or Bay of Rainbows. It is easily visible in binoculars this evening when the sunrise line is crossing the bay. The Jura Mountains will appear as a hook at the upper left edge of the moon. That’s about the coolest sight that’s visible on the moon that can be seen with binoculars. It’s especially striking if seen in a small telescope. Though the bay is the same gray as the rest of the moon, at least its name is colorful.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Bay of Rainbows (Sinus Iridium) within the Jura Mountains on the moon. Created using Virtual Moon Atlas.
Bob Moler's Ephemeris Blog 