Archive
06/09/2017 – Ephemeris – Watch the mini moon rise tonight
Ephemeris for Friday, June 9th. Today the Sun will be up for 15 hours and 29 minutes, setting at 9:26, and it will rise tomorrow at 5:57. The Moon, at full today, will rise at 9:26 this evening.
In recent years we’ve talked about the super moon, when the full Moon appears especially large because it’s at perigee, or closest to the Earth at that time. Well tonight’s full Moon will be a the opposite, a mini Moon. The Moon reached apogee, its farthest from the Earth in it’s orbit at 6:21 last night, and 15 hours later, at 9:10 this morning the Moon was full. However I bet that when the Moon rises tonight that it will appear just as big as it always does, especially if you forget that it’s supposed to be a mini moon. The Moon is in an elliptical orbit of the Earth that this month varies from 252,500 miles (406,400 km) yesterday down to 222,400 miles (357,900 km) on the 23rd. Thanks to the Sun, and especially Jupiter and Venus, those distances change a bit every month. Tonight Saturn will be seen just below the moon.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Mini Moon and Super Moon for 2017. Created using Cartes du Ciel (Sky Charts).
06/06/2017 – Ephemeris – Where did the Moon come from?
Ephemeris for Tuesday, June 6th. Today the Sun will be up for 15 hours and 26 minutes, setting at 9:24, and it will rise tomorrow at 5:57. The Moon, 3 days before full, will set at 5:10 tomorrow morning.
The origin of the Moon is a question that has vexed astronomers for years. Did it break off the molten Earth like a cell dividing? Was it captured by passing too close to the Earth? Neither is satisfactory. Chemical elements have different isotopes depending on the number of neutrons in their nucleus. The rocks brought back by the Apollo astronauts show that the isotopes of the elements in the rocks is that same as for the Earth. We know that Mars and the asteroids have different isotope ratios. The hypothesis that seems most likely is that another planet, the size of Mars collided with the 100 million year old Earth in a glancing blow that gave rise to a disk of material that eventually coalesced into the Moon.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The hypothetical collision of a Mars sized body with the young Earth. Credit: Joe Tucciarone via NASA
05/26/2017 – Ephemeris – Can you spot the extremely young Moon tonight?
Ephemeris for Friday, May 26th. Today the Sun will be up for 15 hours and 11 minutes, setting at 9:15, and it will rise tomorrow at 6:03. The Moon, 1 day past new, will set at 10:16 this evening.
It’s spring and a great time to see if you can spot the young moon. The official time when the moon was new was 3:44 p.m. yesterday afternoon (19:44 UT 25 May 2017), which would make the moon a bit less than 31 hours old if spotted before it sets an hour after the Sun. This requires crystal clear skies and a very low northwestern horizon. Binoculars are a definite help. Spotting the earliest moon after new moon is one of the challenges amateur astronomers pit their observing skills with. Another is the Messier Marathon, in which one tries to observe all 110 of Charles Messier’s catalog entries of dim objects on a single night, which is theoretically possible around March 24th.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
A 39 hour old Moon with Jupiter taken by Greg Hogan on September 2, 2016.
I got this from EarthSky.org. Here’s a search I made of the young moon that has some other images: http://earthsky.org/?s=young+moon
05/17/2017 – Ephemeris – Let’s look at the bright planets for this week
Ephemeris for Wednesday, May 17th. Today the Sun will be up for 14 hours and 54 minutes, setting at 9:06, and it will rise tomorrow at 6:11. The Moon, 1 day before last quarter, will rise at 2:20 tomorrow morning.
Let’s take our weekly look at the bright planets. Mars is still in the west-northwest after sunset and fading. It appears under the left edge of the constellation Auriga. It will set at 10:54 p.m. Dominating the evening sky now is Jupiter in the south-southeast. The bright blue-white star Spica is seen below and left of it. In even the smallest telescopes Jupiter’s four largest moons can be seen. They shift positions night from to night and sometimes even as you watch. Jupiter will set at 4:42 a.m. At 5:30 a.m. both Saturn and Venus will be in the morning twilight. Saturn will be low in the south-southwest. It will rise in the east-southeast at 11:14 p.m. Brilliant Venus will be low in the east tomorrow morning after rising at 4:27 a.m.
For us Mercury, at greatest western elongation of 25.8°will be on the horizon at 5:30, but those south of the equator it will be well placed for viewing in the morning.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Mars and Jupiter with the spring constellations in the fading twilight at 10 p.m., May 17, 2017. Created using Stellarium.
Jupiter and its four Galilean moons as they might be seen in a telescope at 10 p.,. May 17, 2017. Created using Cartes du Ciel (Sky Charts).
Venus, Saturn and the Moon at 5:30 a.m. May 18, 2017. Created using Stellarium. Click on the image to expand.
Saturn and its brightest moons at 5:30 a.m. May 18, 2017. This is displayed at the same scale/magnification as the Jupiter image above. Created using Cartes du Ciel (Sky Charts).
The Moon as it might be seen in binoculars at 5:30 a.m., May 18, 2017. Created using Stellarium.
Venus as seen through a telescope at 5:30 a.m. May 18, 2017. This is displayed at a larger scale/magnification than the Jupiter and Saturn images above. Created using Stellarium.
Planets and the Moon at sunset and sunrise of a single night starting with sunset on the right on May 17, 2017. The night ends on the left with sunrise on May 18. Click on the image to enlarge. Created using my LookingUp program.
05/08/2017 – Ephemeris – Europe and the Chinese are talking about a joint Moon village
Ephemeris for Monday, May 8th. The Sun rises at 6:22. It’ll be up for 14 hours and 33 minutes, setting at 8:55. The Moon, 2 days before full, will set at 6:07 tomorrow morning.
NASA, so far has no plans to return to the Moon to set up a base in preparation to heading out to Mars or an asteroid. That could change. The United States has a problem with long-term goals and planning with a change in administration every 4 or 8 years. The European Space Agency, and the China National Space Administration have no such problem. And it seems that these two entities are talking about together creating a Moon Village. The raw resource that they may hope to mine is Helium 3, which can be used in earthly fusion reactors to produce power. Helium 3 comes via the solar wind from the Sun. A base could be setup at the south pole of the Moon, which has virtually no axial tilt to receive perpetual sunlight for power and water from eternally shadowed crater bottoms.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Artist visualization of a near polar moon base. Credits: ESA/Foster + Partners via Universe Today
I got this story from Universe Today: https://www.universetoday.com/135270/europe-china-discuss-moonbase-partnership/
05/02/2017 – Ephemeris – Puzzling out the Moon’s history
Ephemeris for Tuesday, May 2nd. The Sun rises at 6:30. It’ll be up for 14 hours and 17 minutes, setting at 8:48. The Moon, at first quarter today, will set at 3:06 tomorrow morning.
The Moon will be at exactly first quarter at 10:47 p.m., so it should be split exactly in half by the sunrise line or terminator. On the illuminated face of the Moon can be seen the dark gray spots called seas. In dating the moon rocks brought back by the Apollo astronauts the dates tell the amount of time since the rocks were molten due to collisions. The dates turn out to give clues to when the seas were formed, because they are actually large impact craters, which were filled in by the lava from the moon’s interior. The oldest rocks on the Moon are 4.5 billion years old, dating from the formation of the Moon. There’s another group about 3.9 billion years old dating to when many of the seas were formed in a cataclysm called the late heavy bombardment.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
First quarter Moon with key to the lunar seas. Created using Stellarium.
Sym Latin Name English Name Age A Mare Serenitatis Sea of Serenity 3.85 to 3.92 billion years B Mare Tranquillitatis Sea of Tranquility 3.92 to 4.55 billion years C Mare Nectaris Sea of Nectar 3.85 to 3.92 billion years D Mare Fecunditatis Sea of Fertility 3.92 to 4.55 billion years E Mare Crisium Sea of Crises 3.85 to 3.92 billion years F Mare Frigoris Sea of Cold 3.85 to 4.55 billion years
Data are from Virtual Moon Atlas
04/03/2017 – Ephemeris – A two bit* Moon today
Ephemeris for Monday, April 3rd. The Sun will rise at 7:19. It’ll be up for 12 hours and 53 minutes, setting at 8:12. The Moon, at first quarter today, will set at 3:38 tomorrow morning.
The Moon will be at exactly first quarter at 2:12 this afternoon (18:12 UT). By this evening for us the terminator line, which is the sunrise line on the Moon as the Moon’s phase waxes will be bowed to the left a bit. The names of the primary phases of the Moon are a bit odd. The quarter moons are named for their positions one quarter or 90 degrees from the Sun. The full moon describes it appearance as fully illuminated. New moon is odd too. To the Jews and the Arabs the New moon was the name for the first sighting of the crescent Moon after it disappeared from the morning sky. Astronomers use that term today for when the Moon is in conjunction with the Sun, day zero of a lunation or lunar month, about a day before its first appearance in the evening.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
* If “two bit” is foreign to you. It dates back to US colonial times when the most prevalent coin around was the Spanish Dollar, also known as a piece of eight. A quarter of that was two bits, 25 cents in modern parlance. It lives on in the tune and knock sequence “Shave and a haircut, two bits” or five rapid knocks a pause and two more. See the movie “Who Framed Roger Rabbit?”.
Addendum
This is the best diagram of the Moon’s phases and how the it appears from the Earth. Credit http://planetfacts.org/phases-of-the-moon/ which I recommend.
However I do not like the label Dark Side. It is simply the night side. The Far Side is what many people mistakenly call the dark side, because we can never see it from the Earth. However the far side sees more sunlight than the near side. One, it is never darkened by an eclipse of the Moon, because it’s night-time there normally at that time. Two, at new moon it is fully facing the Sun, and also a quarter of a million miles closer to the Sun than the Earth is. So how can it be the dark side. Really. Come on people.
03/07/2017 – Ephemeris – The Moon tonight – the crater Copernicus
Ephemeris for Tuesday, March 7th. The Sun will rise at 7:08. It’ll be up for 11 hours and 29 minutes, setting at 6:38. The Moon, 2 days past first quarter, will set at 4:39 tomorrow morning.
Looking at the Moon tonight the brightest feature on the left side of the moon is the big splash mark left by the impact that created the crater Copernicus. The proper term is ejecta blanket that can be noticed by the naked eye or binoculars. Although it is most visible during full moon, because it is really made of small craters that are most visible when we see them from the direction of the Sun, so they are not shadow filled and brighter than normal. Copernicus is on the south edge of a great lava plain called Mare Imbrium, the Sea of Showers. There’s a large crater on the north edge named after the Greek philosopher Plato. At the upper left edge is the Laplace promontory the point of the Bay of Rainbows to be revealed tomorrow night.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Moon featuring Copernicus, Plato, Laplace Promontory and Mare Imbrium at 9 p.m., March 7, 2017. Created using Virtual Moon Atlas.
02/14/2017 – Ephemeris – Is the Moon waxing or waning?
Ephemeris for St Valentine’s Day, Tuesday, February 14th. The Sun will rise at 7:43. It’ll be up for 10 hours and 26 minutes, setting at 6:10. The Moon, half way from full to last quarter, will rise at 10:18 this evening.
This morning the waning gibbous moon will be a way to the right of the bright planet Jupiter which is in the southwest at 7 a.m. Tomorrow morning the Moon will appear above and right of Jupiter. My granddaughter is taking earth science in school now and is confused about when the Moon is waxing or waning. If it’s waxing it is getting fuller each night. If waning the Moon’s phase is getting thinner each night. But I told her that if you can see the Moon in the evening it’s waxing, and if you can see the Moon in the morning it’s waning. It works except around full Moon where you’d need a calendar for the full moon date or if it rises before or after sunset.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
A graphic explaining the Moon’s position with respect to the Earth and Sun (which is off the diagram to the right). The Moon orbits the Earth in a counterclockwise direction. Credit NASA/Bill Dunford.
02/06/2017 – Ephemeris – The Moon is at perigee today
Ephemeris for Monday, February 6th. The Sun will rise at 7:54. It’ll be up for 10 hours and 4 minutes, setting at 5:58. The Moon, 3 days past first quarter, will set at 4:56 tomorrow morning.
At 9 this morning the Moon will be at perigee, the closest it gets to the Earth in its current orbit of the Earth. Had the Moon been full it would be called a super-moon. The Moon isn’t just orbiting the Earth, but it is also pushed around by the Sun, which has a greater hold on he Moon than the Earth, but also by Jupiter and Venus, plus all the other objects in the solar system to a far lesser degree. You are not going to see it rise this afternoon at 1:48, so the big Moon on the horizon optical illusion doesn’t come into play. It will appear its highest at 9:21 this evening, some 63 degrees above the horizon. By then it will be some 3500 miles or so closer than when it’s on the horizon, because we’re on the Moon facing side of the Earth. Look up, there the Moon doesn’t really look very big at all, does it?
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Moon and the stars tonight at 9:21 p.m. Don’t be fooled by the size of the Moon. Here it appears 4 times its actual diameter, and 16 times its area in this image. It actually appears really small. But it will appear a lot bigger when it sets due to the horizon illusion. Created using Stellarium.
Bob Moler's Ephemeris Blog 