Archive
01/26/2018 – Ephemeris – The Moon tonight: The Bay of Rainbows
Ephemeris for Friday, January 26th. The Sun will rise at 8:08. It’ll be up for 9 hours and 34 minutes, setting at 5:43. The Moon, 2 days past first quarter, will set at 3:59 tomorrow morning.
A look at the Moon tonight will reveal that the sunrise line, or terminator has almost completely revealed the large sea of Showers or Mare Imbrium to the upper left of center of the gibbous disk. At the extreme upper left straddling the terminator is one of my favorite features, the Bay of Rainbows or Sinus Iridium. It’s a colorful name for something that’s as gray as the rest of the Moon. It looks like a bay off of Imbrium, and has an arch like a rainbow. It’s arch is the Jura Mountains, which jut into Mare Imbrium at Cape Heraclide, just catching sunlight, and Cape Laplace farther into morning. What’s cool is catching it as the sunlight is hitting the mountains while the convex floor, following the Moon’s curvature is only partially illuminated.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Moon at 8 p.m. January 26, 2018 highlighting Sinus Iridium. Created using Virtual Moon Atlas.
Sinus Iridium photographed by the Lunar Reconnaissance Orbiter as texture mapped on the globe of the Virtual Moon Atlas.
Sinus Iridium at sunrise. Photo by “Seb2003” on http://forums.futura-sciences.com/materiel-astronomique-photos-damateurs/5809-images-de-lune.html.
01/25/2018 – Ephemeris – The Moon tonight: Copernicus on the terminator
Ephemeris for Thursday, January 25th. The Sun will rise at 8:09. It’ll be up for 9 hours and 32 minutes, setting at 5:41. The Moon, 1 day past first quarter, will set at 2:48 tomorrow morning.
Let’s take a look at our slightly gibbous moon, just a day past first quarter with binoculars or a small telescope. The terminator, in this case the sunrise line will appear to cross the crater Copernicus to the right of the Moon’s center if you’re viewing it right side up. To the North across the Sea of Showers, or Mare Imbrium is the large flat floored crater Plato. South of Copernicus is a recently named sea, Mare Cognitum, the Known Sea, after the first successful close photography by the Ranger 7 spacecraft in 1964. South of the is Mare Nubium, the Sea of Clouds. South of that are the lunar highlands with the stark crater Tycho and the huge crater Clavius with an arc of craters of decreasing size within it.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The waxing gibbous Moon tonight at 8 p.m., January 25, 2018. Created using Virtual Moon Atlas.
The crater Copernicus. Credit: NASA/GSFC/Arizona State University.
The Lunar highlands near the crater Tycho showing a surface saturated with craters. Credit: Virtual Moon Atlas with the texture from NASA’s Lunar Reconnaissance Orbiter. The lunar phase was omitted.
Clavius as photographed by one of the Lunar Orbiter spacecraft in the 1960s From Digital Lunar Orbital Photographic Atlas. Credit Jeff Gillis, Lunar and Planetary Institute.
01/24/2018 – Ephemeris – Our weekly look at the bright planets
Ephemeris for Wednesday, January 24th. The Sun will rise at 8:10. It’ll be up for 9 hours and 30 minutes, setting at 5:40. The Moon, at first quarter today, will set at 1:38 tomorrow morning.
Let’s take our weekly look at the bright planets. All of the bright naked eye planets save one are in the morning sky now, but Venus sets only 14 minutes after the Sun. At 7 this morning Jupiter is in the south-southeast and is a lot brighter than Mars, below and left of it. Saturn is very low in the southeast. Jupiter will rise at 2:44 a.m. tomorrow with Mars following at 3:30. And Saturn will rise at 6:15. Saturn’s rise times will increase by 3 to 4 minutes each morning. It will be in a lot better position to spot in the coming weeks. The morning sky you’ll see at 7 a.m. will be the same stars as in the early summer sky with the summer triangle in the east. Scorpius is rising with the red star Antares below and left of Mars.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The first quarter Moon as it might be seen in binoculars at 8 p.m. tonight. January 24, 2017. Created using Stellarium.
Jupiter and Mars are easily visible, but Saturn is low in the southeast at 7 this the morning, January 24, 2018. Click on the image to enlarge. Created using Stellarium.
Jupiter and its moons at 7 a.m. this morning January 25, 2018. Created using Cartes du Ciel (Sky Charts).
Planets at sunset and sunrise of a single night starting with sunset on the right on January 24, 2018. The night ends on the left with sunrise on the 25th. Click on the image to enlarge. Created using my LookingUp program.
01/23/2018 – Ephemeris – The Moon tonight: the Sea of Tranquility and a crater named for Julius Caesar
Ephemeris for Tuesday, January 23rd. The Sun will rise at 8:10. It’ll be up for 9 hours and 28 minutes, setting at 5:38. The Moon, 1 day before first quarter, will set at 12:30 tomorrow morning.
Let’s take a look at the Moon tonight with binoculars or a small telescope. The crescent Moon tonight has completely revealed the Sea of Tranquility, or Mare Tranquillitatis. Right on the western edge, east to us, of the sea is a ruined crater called Julius Caesar. It seems to have formed by a small asteroid collision in the first half billion years of the Moon’s existance. It’s shape was distorted by the impact that created the Sea of Tranquility. The Moon’s so-called seas are all pretty much impact craters, just really big ones. North of Tranquility is the Sea of Serenity which will be completely in sunlight tomorrow night. By the way, the Grand Traverse Astronomical Society telescope clinic that was scheduled for January has been moved to February 2nd.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The fat crescent Moon at 8 p.m. January 23, 2018. Created using Virtual Moon Atlas.
The crater Julius Caesar from photographs supplied with Virtual Moon Atlas.
01/22/2018 – Ephemeris – The Pup
Ephemeris for Monday, January 22nd. The Sun will rise at 8:11. It’ll be up for 9 hours and 25 minutes, setting at 5:37. The Moon, 2 days before first quarter, will set at 11:24 this evening.
Sirius is the brightest night-time star and is located in the southeast at 9 p.m. below and a bit left of Orion the Hunter. We’ve visited Sirius last week. There is another star in the Sirius system that is practically invisible due to its dazzling glare. It’s Sirius B, nicknamed the Pup, alluding to Sirius’ Dog Star title. The tiny star was suspected as far back as 1834 due to Sirius’ wavy path against the more distant stars. Sirius is only 8.6 light years away. Sirius A and the Pup have 50 year orbits of each other. The star was first seen by Alvan Clark in 1862 while testing a new telescope. The Pup was the first of a new class of stars called white dwarfs. The Pup is about the size of the Earth, with the mass of our Sun, and 5 times hotter than the Sun’s surface. It’s out of fuel and slowly collapsing.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Orion and Canis Major Animation for 9 p.m. January 20, 2017. Created using Stellarium and GIMP.
Sirius A & B’s path in the sky showing the wobble that betrayed the Pup’s presence. Credit Mike Guidry, University of Tennessee.
Sirius A and B (near the diffraction spike to the lower left), A Hubble Space Telescope photograph. Credit NASA, ESA.
01/19/2018 – Ephemeris – Orion’s large hunting dog
Ephemeris for Friday, January 19th. The Sun will rise at 8:14. It’ll be up for 9 hours and 19 minutes, setting at 5:33. The Moon, 3 days past new, will set at 8:15 this evening.
The brightest star-like object in the evening sky is Sirius, also known as the Dog Star. It also is the brightest night-time star in our skies period. Tonight at 9 p.m. it’s located low in the southeastern sky. The Dog Star name comes from its position at the heart of the constellation Canis Major, the great dog of Orion the hunter, which is seen almost like he’s begging, feet to the right. The three stars of Orion’s belt tilt to the southeast and point to Sirius. The name Sirius means ‘Scorcher’, a reference to its great brilliance and twinkling. To me it has a blue tinge like an arc light in a telescope. Its Egyptian name was Sothis, and its appearance in the dawn skies in late June signaled the flooding of the Nile, and the beginning of the Egyptian agricultural year.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Orion and Canis Major Animation for 9 p.m. tonight. Created using Stellarium and GIMP.
01/18/2018 – Ephemeris – The spectacular Great Orion Nebula
This is Bob Moler with Ephemeris for Thursday, January 18th. The Sun will rise at 8:14. It’ll be up for 9 hours and 17 minutes, setting at 5:32. The Moon, 2 days past new, will set at 7:15 this evening.
The constellation Orion the hunter is the south-southeast at 9 p.m. its upright rectangle of four stars frame his belt of three stars in a straight line and still tilt a bit to the left. Below the belt is what appear to the unaided eye as three more stars arranged vertically, his sword. Binoculars aimed at the middle stars of the sword will find a glowing haze around those stars. That is the Great Orion Nebula. It is the birth place of stars, and is even illuminated by a clutch of four hot young stars. One of the discoveries of the Hubble space telescope are what appear, and are tiny cocoons of gas and dust in which stars condense and form. They are called Proplyds, which are short for protoplanetary disks. In each one is the red center, a young star just beginning to shine.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The lower part of Orion with the Great Orion Nebula. Created using Stellarium.
The Great Orion Nebula (M42) long exposure photograph by Scott Anttila. Includes all the sword stars.
A new video just posted by NASA
01/17/2018 – Ephemeris – Our weekly look at the bright planets
Ephemeris for Wednesday, January 17th. The Sun will rise at 8:15. It’ll be up for 9 hours and 15 minutes, setting at 5:31. The Moon, 1 day past new, will set at 6:17 this evening.
Let’s take our weekly look at the bright planets. All of the bright naked eye planets save one are in the morning sky now, but Venus sets 2 minutes after the Sun. At 7 this morning Jupiter is in the south-southeast and is a lot brighter than Mars, below and left of it. Saturn is just rising in the southeast. Jupiter will rise at 3:07 tomorrow with Mars following at 3:35. And Saturn will rise at 6:39. Saturn’s rise times will increase by 3 to 4 minutes each morning. It will be in a lot better position to spot in the coming weeks. The morning sky you’ll see at 7 a.m. will be the same stars as in the late spring sky with the summer triangle just rising. Scorpius is rising with the red star Antares below left of Mars, and Orion as I mentioned yesterday has fled over the western horizon.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Jupiter and Mars are easily visible, but Saturn is low and problematic at 7 in the morning. Created using Stellarium.
Jupiter and its moons at 7 a.m. this morning January 17, 2018. Io and Europa will be eclipsed and occulted by Jupiter after this time.
Planets at sunset and sunrise of a single night starting with sunset on the right on January 17, 2018. The night ends on the left with sunrise on the 18th. Click on the image to enlarge. Created using my LookingUp program.
01/16/2018 – Ephemeris – More thoughts about Orion and the Wintermaker
Ephemeris for Tuesday, January 16th. The Sun will rise at 8:15. It’ll be up for 9 hours and 13 minutes, setting at 5:29. The Moon is new today, and won’t be visible.
We come back to the central constellation of the winter sky Orion the hunter, now in the southeast at 9 p.m. with his three stars of his belt in a straight line, with his upper shoulder stars above and knees below. In one Greek story he was killed by the sting of a scorpion so the gods made sure the rising of the constellation Scorpius would chase him out of the sky to the west. To the Greeks he was a hapless hero. Orion is mentioned in the Bible in the book of Job. The name for Orion in Hebrew is Kesil, meaning “Fool”. To the native peoples around the Great Lakes, the stars here are those of the Wintermaker, who stretches his arms from Aldebaran in Taurus to Procyon in Canis Minor. When he is in the evening sky it is indeed winter.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
When the scorpion (Scorpius) crawls over the southeastern horizon, Orion takes a powder to the west. This is about 5 a.m. in mid January. Created using Stellarium.
Orion-Wintermaker finder animation for 9 p.m., January 16. Created using Stellarium and GIMP.
01/15/2018 – Ephemeris – A river in the sky
Ephemeris for Martin Luther King Day, Monday, January 15th. The Sun will rise at 8:16. It’ll be up for 9 hours and 11 minutes, setting at 5:28. The Moon, 1 day before new, will rise at 7:49 tomorrow morning.
There is a long and sinuous constellation that’s part of the winter sky. It is Eridanus, which depicts a river. The river starts near the lower right corner of Orion, near the bright star Rigel and flows to the right then down near the southern horizon, then it meanders below the horizon. One has to travel to the far southern United States or even farther south to see the southern terminus of the river, the bright star Achernar. Writers over the ages have seen here the Nile and the earth circling river Ocean of the flat earth days. One of its stars is close to us and famous. It’s Omicron 2 Eridani a triple star system and the fictional home to Mr. Spock and other Vulcans of the Star Trek franchise. No real planet has been found there. Yet.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
An animation of the constellation Eridanus which is a river that flows from Rigel in Orion to the star Achernar below our southern horizon at latitude 45 degrees north. Create using Stellarium and GIMP.
Keid, Omicron 2 Eridani, fictional home of Mr. Spock. Created using Stellarium.
