Archive
04/15/11 – Ephemeris – Naming lunar features
Friday, April 15th. The sun rises at 6:58. It’ll be up for 13 hours and 28 minutes, setting at 8:27. The moon, 2 days before full, will set at 5:41 tomorrow morning.
If you’ve notices that the names we use for features on the moon sound familiar when used in other contexts, you’re right. Lunar craters are named for astronomers, scientists, philosophers and explorers. The mountains on the moon are named for earthly mountain ranges. The great lava plains, misnames seas are given fanciful names like the Sea of Tranquility, which I usually leave in the original Latin. In this case Mare Tranquilitatis. The naming convention for craters pretty much holds for the other bodies of the solar system. The next bodies to get crater names will be Mercury, which the MESSENGER spacecraft went into orbit of last month and the asteroid Vesta, which the Dawn spacecraft will reach in July.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
See this Wikipedia article on planetary nomenclature.
04/14/11 – Ephemeris – The gibbous moon
Thursday, April 14th. The sun will rise at 7:00. It’ll be up for 13 hours and 25 minutes, setting at 8:25. The moon, half way from first quarter to full, will set at 5:13 tomorrow morning.
The moon tonight is in its gibbous phase. The word gibbous means hump backed. At this phase the moon is severely interfering with the dimmer stars. So looking at the moon with a telescope becomes a good option. The moon will be bright and ruin any dark adaption your eye had before looking at it. Remember the sun shines on the moon with the same strength that it does on the earth, since it’s at roughly the same distance from the sun as the earth. The brightest spot on the earth facing side of the moon will be emerging into the lunar morning light this evening. It will be showing that brightness in a few days, but now it is the crater at the upper left edge of the moon, just coming into light. It is the crater Aristarchus.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The gibbous moon for April 14, 2011. Created using Virtual Moon Atlas.
The crater Aristarchus is moving into the morning lunar daylight.
04/11/11 – Ephemeris – First quarter moon
Monday, April 11th. The sun will rise at 7:05. It’ll be up for 13 hours and 16 minutes, setting at 8:22. The moon, at first quarter today, will set at 3:45 tomorrow morning.
Lets take a look at the moon tonight. It’ll be about 14 hours after first quarter and we see features at the terminator, the sunrise line that cuts the moon in half. In small telescopes, at the north or top end of the moon, the wide flat crater Plato has just entered sunlight. Long shadows from its crater walls will retreat across its flat floor. If you look closely you’ll notice that the floor of Plato is slightly convex to conform with the curvature of the moon itself. Nearby is the straight gash in the Alps Mountains, called the Alpine Valley. Supposedly the crater Plato formed shortly after Mare Imbrium formed throwing up the Alps and the Apennine mountains to the south. The Straight wall, another straight feature can be seen on the south end of the moon.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
First quarter moon April 11, 2011 Created using Virtual Moon Atlas
What’s wrong with this picture?
I received this in an email. The picture’s pretty but is it real? If not, what’s wrong? Answer in the comments.
Sunset at the North Pole. This is one of the rarest picture that you mayever see in your life when the moon was closest to the earth. The date: Jan 13, 2011.This is the sunset at the North Pole with the moon at its closest point last week. a scene you will probably never get to see in person, so take a moment and enjoy God at work at the North Pole. And, you also see the sun below the moon, an amazing photo and not one easily duplicated. You may want to pass it on to others so they can enjoy it. The Chinese have a saying that goes something like this: 'When someone shares with you something of value, you have an obligation to share it with others!'
03/15/11 – Ephemeris – The Lunar Highlands
Ephemeris for Tuesday, March 15th. The sun will rise at 7:55. It’ll be up for 11 hours and 52 minutes, setting at 7:48. The moon, half way from first quarter to full, will set at 5:48 tomorrow morning.
The south part of the moon that can be seen tonight appears brighter than the darker areas that we call seas, that make up the face of the man in the moon. These and other bright areas are called the lunar highlands, and are the most primitive surface of the moon. Here the landscape is saturated with craters. In binoculars the crater Tycho with its rays are just beginning to become prominent. These rays, are thought to be small craterlets caused by the ejecta from the creation of Tycho which occurred perhaps less than 1.1 billion years ago. This makes Tycho a relatively fresh crater in the moon’s nearly 4.5 billion year history. A telescope will reveal more, including the large crater Clavius with its arc of smaller craters within.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
03/14/11 – Ephemeris – The Lunar Jura Mountains
Ephemeris for Monday, March 14th. The sun will rise at 7:57. It’ll be up for 11 hours and 49 minutes, setting at 7:46. The moon, 3 days past first quarter, will set at 5:13 tomorrow morning.
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. It is easily visible in binoculars this evening when the sunrise line is crossing the bay. The Jura Mountains will appear as a hook out of 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. I’ve added these programs to my web log or blog and I can add images to illustrate what I’m talking about, as I did today. The blog’s address is bobmoler.wordpress.com.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Jura Mountains sticking up into morning daylight. Created from the Virtual Moon Atlas.
03/10/11 – Ephemeris – The moon will appear near the Pleiades tonight
Thursday, March 10th. The sun will rise at 7:04. It’ll be up for 11 hours and 37 minutes, setting at 6:41. The moon, 2 days before first quarter, will set at 12:54 tomorrow morning.
The fat crescent moon tonight will be near the Pleiades or Seven Sisters star cluster. The Pleiades can be seen above the moon. They will make a very beautiful sight in binoculars. They will be closest together near 2 in the morning. Some years the moon will even pass in front of the stars of the Pleiades. On the moon itself tonight, in binoculars, we can see the dark lunar seas of Crises, Fertility, Nectar, and Tranquility. With a telescope the crater Theophilus is visible near the terminator, the sunrise line a bit below center of the moon. It is a perfect circular crater with a central peak. The best crater visible now. That will change as the moons phase becomes fuller. It will appear washed out and indistinct. The moon needs shadows to delineate its features.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Blog addendum:
Pleiades and the moon 03/10/11, created using Cartes du Ciel.
Here’s a closer look at the moon courtesy of Virtual Moon Atlas.
Young moon with the crater Theophilus and four seas. From Virtual Moon Atlas
03/08/11 – Ephemeris – The lunar sea of Crises
Fat Tuesday, March 8th. The sun will rise at 7:08. It’ll be up for 11 hours and 31 minutes, setting at 6:39. The moon, half way from new to first quarter, will set at 10:51 this evening.
The one feature that is prominent on the crescent moon tonight will be the dark sea Mare Crisium or sea of Crises. It appears easily in binoculars. It, as all the lunar seas, are really a large crater that was created about 3.85 billion years ago by an asteroid strike. It appears foreshortened because it’s near the moon’s limb. If you watched the proximity of Mare Crisium to the edge of the moon over time, you’d notice that sometimes it’s closer to the edge than at other times. The moon has a constant rotation, but its orbit isn’t circular, so the moon appears to rock back and forth slowly, and nods a bit too. The effect is called libration, and allows us to see 60% of the moon from earth.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Blog Addendum:
Below is an image from Virtual Moon Atlas pointing out Mare Crisium, the Sea of Crises. VMA is a free program. See the links for free programs on this blog.
Mare Crisium via Virtual Moon Atlas
03/07/11 – Ephemeris – Earthshine
Monday, March 7th. The sun will rise at 7:09. It’ll be up for 11 hours and 28 minutes, setting at 6:37. The moon, 3 days past new, will set at 9:49 this evening.
The moon tonight will appear as a thin sliver, with not much visible on the thin illuminated portion. However if as you look at the moon tonight you have the funny feeling that the whole moon is visible, you are right. It’s easily confirmed with a pair of binoculars or a small telescope. What is illuminating the dark part of the moon is earthshine. The earth is big and bright in the moon’s sky, and nearly full from its vantage point. The effect used to be called by the term “Old moon in the new moon’s arms”. The effect was first explained by Leonardo DaVinci some 500 years ago. The effect will disappear in a few days as the moon gets brighter and the earth less so in the moon’s sky. Earthshine will appear again when the moon appears as a waning crescent in the morning.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Update:
Earthshine is notoriously hard to photograph. Here’s one of mine from 1991. Part of a planetary conjunction picture with a short focal length telephoto lens. I’ve cropped out the planets. The sunlit side of the moon is vastly overexposed causing the blooming in the photograph.
Earthshine on the crescent moon
02/11/11 – Ephemeris – The moon will appear near the Pleiades tonight
Friday, February 11th. The sun will rise at 7:48. It’ll be up for 10 hours and 16 minutes, setting at 6:05. The moon, at first quarter today, will set at 3:05 tomorrow morning.
Today the moon will pass below the Pleiades or Seven Sisters star cluster. It does this once a month, but maybe tonight the moon won’t be too bright to completely drown them out. The Pleiades is a relatively nearby star cluster about 440 light years away. It is easily visible to the unaided eye, but not with the bright moon nearby. Binoculars will help bring out the cluster, which may show many more stars. On the moon two of the great features for small telescopes are visible, the wide flat floored crater Plato and the Straight Wall. Plato is visible at the upper part of the moon, while the Straight Wall is below center on the moon as a thin black line. It’s hard to spot for the first time. It is nearly a sheer fault 67 miles long and 900 feet high with a slope of 30 to 40 degrees.
* Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Extra
The Moon near the Pleiades, February 11, 2011 9 p.m. EST. Created using Cartes du Ciel (Sky Charts)
Lunar crater Plato and the fault Straight Wall
This is not a photograph! Image created using Virtual Moon Atlas by Christian Legrand and Patrick Chevalley. A free program. http://www.ap-i.net/avl/en/start.
Closeup of the Straight Wall
Image also created using Virtual Moon Atlas.
Bob Moler's Ephemeris Blog 