Archive
06/27/2023 – Ephemeris – Preparing to view the upcoming solar eclipses safely
This is Ephemeris for Tuesday, June 27th. Today the Sun will be up for 15 hours and 33 minutes, setting at 9:32, and it will rise tomorrow at 5:59. The Moon, 1 day past first quarter, will set at 2:21 tomorrow morning.
In preparation for the two solar eclipses that will be visible in North America in the next 10 months, I’m going to spend some time describing what the Sun is, and how it appears to us. First point: Never look at the Sun without proper and approved filters. Inexpensive eclipse glasses work fine for the partial phase of a solar eclipse. However, most features, like sunspots, are generally too small to be seen with them. Do not use these glasses with binoculars or a telescope. The plastic filters will melt through in a fraction of a second. Glass filters can shatter from the heat. The only safe solar filter for telescopes is one placed in front of the telescope tube, so it’s only exposed to ambient light and heat. If confused, just ask your local amateur astronomer.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location.
Addendum
06/26/2023 – Ephemeris – After the latest sunset, a look at the Moon
This is Ephemeris for Monday, June 26th. Today the Sun will be up for 15 hours and 33 minutes, setting at 9:32, and it will rise tomorrow at 5:59. The Moon, at first quarter today, will set at 2:02 tomorrow morning.
Tonight is the night of the latest sunset. From now to December 10th the Sun will be setting earlier than the night before. It won’t be noticeable at first, but the change will increase throughout the summer. The Moon actually arrived at first quarter phase early this morning, so by tonight it will appear slightly gibbous. The term gibbous actually means hump-backed, and the Moon will appear more so as it advances toward being fully illuminated a week from now. For me personally, I find that the best time to view the Moon with a telescope is within three or four days from its quarter phase, unless I’m looking at a specific feature. That’s when shadows are front and center on the moon. The Moon being gray on gray, shadows keep the Moon from appearing flat.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location.
Addendum
06/22/2023 – Ephemeris – The lunar seas on tonight’s Moon
This is Ephemeris for Thursday, June 22nd. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:32, and it will rise tomorrow at 5:57. The Moon, halfway from new to first quarter, will set at 12:51 tomorrow morning.
The crescent Moon tonight reveals two large seas. Astronomers using the first telescopes thought the darker flat areas on the moon may actually be filled with water. It turns out that they are flat lava plains, and since most of them are roughly circular, may be gigantic craters from impacts of asteroids. Examination of rocks brought back by the Apollo astronauts over 50 years ago suggest the age of the seas at around 4 billion years. This suggests some kind of disruption in the solar system, called the Late Heavy Bombardment. The reason the Earth does not have these scars is due to plate tectonics and the weathering of wind and water. The Moon has none of these, so it preserves the damage done to it.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location.
Addendum
Late Heavy Bombardment (Based on my August 4, 2022 post)
There are even more and larger seas on the east half of the Moon, as we see it. Most were created about 3.9 billion years ago by asteroid strikes. The same thing happened to the Earth, but plate tectonics destroyed the evidence. Not so on the Moon. The result, many planetary scientists think, was the Late Heavy Bombardment, caused by the shifting orbits of mainly Saturn, Uranus and Neptune that disrupted the smaller asteroids, and sending them careening through the solar system.
06/21/2023 – Ephemeris – Let’s find out where the naked-eye planets have wandered off to this week
This is Ephemeris for Wednesday, June 21st. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:32, and it will rise tomorrow at 5:57. The Moon, 3 days past new, will set at 12:27 tomorrow morning.
Let’s find out where the naked-eye planets have wandered off to this week. Looking below the horizon we see our planet, which will reach the June solstice and the beginning of summer in the northern hemisphere later this morning (10:58 am EDT, 14:58 UT). Venus is our blazing Evening Star seen in the west all evening. It will still set after midnight, but barely. Tonight it is seen below the Moon. The red planet Mars is seen left of and a bit higher than Venus by four and a half degrees, or a bit less than half the width of one’s fist held at arm’s length. Venus is closing the gap between them, but will never quite reach Mars while they are in the evening sky. The closest they will get is three and a half degrees or 7 moon diameters apart, before Venus pulls back toward the Sun faster than Mars will. Both Mars and Venus are in Cancer. In the morning, Saturn will be visible low in the south-southeast at 5 am. Jupiter will be low in the east at that hour.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location.
Addendum
06/14/2023 – Ephemeris – Let’s find out where the naked-eye planets have wandered off to this week
This is Bob Moler with Ephemeris for Flag Day, Wednesday, June 14th. Today the Sun will be up for 15 hours and 33 minutes, setting at 9:29, and it will rise tomorrow at 5:56. The Moon, half way from last quarter to new, will rise at 3:59 tomorrow morning.
Let’s find out where the naked-eye planets have wandered off to this week. Venus is our blazing Evening Star seen in the west all evening. It will set after midnight. The red planet Mars is seen left of and a bit higher than Venus by six and a half degrees, or a bit more than half the width of one’s fist held at arm’s length. Venus is closing the gap between them, but will never quite reach Mars while they are in the evening sky. The closest they will get is three and a half degrees or seven moon diameters apart, before Venus pulls back toward the Sun faster than Mars will. Both Mars and Venus are in Cancer. In the morning, Saturn will be visible low in the south-southeast at 5 am. Jupiter will be very low in the east at that hour.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location.
Addendum
06/13/2023 – Ephemeris – Messier 13, the Great star cluster in Hercules
This is Bob Moler with Ephemeris for Tuesday, June 13th. Today the Sun will be up for 15 hours and 32 minutes, setting at 9:29, and it will rise tomorrow at 5:56. The Moon, 3 days past last quarter, will rise at 3:34 tomorrow morning.
About a third of the way between the bright stars Vega which is high in the east and Arcturus, high in the south, can be found the Keystone of Hercules, a four-star box wider at the top than at the bottom. Along the right edge, a third of the way down is what looks like a faint star to someone with really good vision. In binoculars the star becomes fuzzy. One needs a larger telescope probably six or eight inches in diameter to begin to see some stars among the fuzziness. That is a globular star cluster containing hundreds of thousands of stars. This is the Great Hercules Globular Star Cluster. It’s beautiful if seen in a large telescope, such as the one brought out to the star parties at the Sleeping Bear Dunes, especially in August and September.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location.
Addendum
Dan’s image is rotated from Scott’s. The bright star at the lower left of Scott’s image is the same as the one at the lower left of Dan’s.
Globular star clusters are uniformly very old. M 13 is estimated to be between 11 and 12 billion years old, more than twice as old as our Sun and the solar system. As I say in my talks: “They don’t make them like that any more.” Globular clusters form a spherical distribution around the Milky Way galaxy with an increasing concentration toward the center. Do they reveal the original spherical shape of the galaxy before the gas and dust collapsed into the disk of the galaxy we see today? The star clusters that form today lie in the disk, and contain a few hundreds or a thousand stars. They are called open or galactic star clusters. The Pleiades is the most famous example of this type of star cluster.
06/12/2023 – Ephemeris -Finding Hercules among the stars
This is Ephemeris for Monday, June 12th. Today the Sun will be up for 15 hours and 31 minutes, setting at 9:28, and it will rise tomorrow at 5:56. The Moon, 2 days past last quarter, will rise at 3:13 tomorrow morning.
Orion, the hard luck mythical Greek hunter, gets a splashy constellation in the winter sky, but the greatest hero of all, Hercules, gets a dim group of stars on the border between the spring and summer stars. At 11 p.m. Hercules is high in the east-southeast. It is located above and right of the bright star Vega, in the east. Hercules’ central feature is a keystone shaped box of stars, called, of course, the Keystone of Hercules tilted to the left, which represents the old boy’s shorts. From the top and left corner stars extend lines of stars that are his legs, from the bottom and right stars, the rest of his torso and arms extend. So in one final indignity, he’s upside down in our sky. For those with a telescope, Hercules contains the beautiful globular star cluster Messier 13.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location.
Addendum
06/09/2023 – Ephemeris – How to find Corona Borealis, the Northern Crown
This is Bob Moler with Ephemeris for Friday, June 9th. Today the Sun will be up for 15 hours and 29 minutes, setting at 9:27, and it will rise tomorrow at 5:57. The Moon, 1 day before last quarter, will rise at 2:13 tomorrow morning.
High in the southeast at 11 p.m. can be found a small but easily spotted constellation of Corona Borealis, the Northern Crown. It is located just east or left of the kite shaped constellation of Boötes, with its bright star Arcturus at the bottom. The Northern Crown is a three-quarters circle of stars, like a tiara, with a brighter star Alphecca at the bottom. Alphecca in Arabic means “Bright star of the broken ring of stars”. According to Greek mythology it belonged to Princess Ariadne, daughter of King Minos of Crete who helped Theseus escape from the Labyrinth of the Minotaur, only to be abandoned by him on an island. To the Native Chippewa and Ottawa of our area it is the Sweat Lodge.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location.
Addendum
Next Monday I will post about Hercules.
06/08/2023 – Ephemeris – The first stars that appear tonight
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06/07/2023 – Ephemeris – Let’s find where the naked-eye planets have wandered off to this week
This is Bob Moler with Ephemeris for Wednesday, June 7th. Today the Sun will be up for 15 hours and 27 minutes, setting at 9:25, and it will rise tomorrow at 5:57. The Moon, 3 days before last quarter, will rise at 1:18 tomorrow morning.
Let’s find where the naked-eye planets have wandered off to this week. Venus is our blazing Evening Star seen in the west all evening. It will set after midnight. The red planet Mars is seen left of and a bit higher than Venus by eight and a half degrees, or a bit less than the width of one’s fist held at arm’s length. Venus is closing the gap between them, but will never quite reach Mars while they are in the evening sky. The closest they will get is three and a half degrees or 7 moon diameters apart, before Venus pulls back toward the Sun faster than Mars will. Both Mars and Venus are in Cancer. In the morning, Saturn will be visible low in the southeast at 5 am, rising at 1:53 am. Jupiter is low in the east at that hour, rising at 3:57 am.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location.
Addendum
Bob Moler's Ephemeris Blog 