Archive
Ephemeris: 05/29/2024 – Where have the naked-eye planets wandered off to this week?
This is Ephemeris for Wednesday, May 29th. Today the Sun will be up for 15 hours and 17 minutes, setting at 9:19, and it will rise tomorrow at 6:01. The Moon, 1 day before last quarter, will rise at 2:31 tomorrow morning.
Let’s find out where the naked-eye planets have wandered off to this week, and see what planets are left. Venus, Mercury and Jupiter are now too close to the direction of the Sun to be seen. Venus will appear in the evening sky by July, while Jupiter may be visible in the morning in late June. By 5:15 tomorrow morning, or about 45 minutes before sunrise, Saturn will be low in the southeast and Mars will be lower still in the east. In telescopes, Saturn will look fairly different this year and next with its rings nearly edge on to us. They will open up a bit through October before closing again. We won’t see the rings go exactly edge on because Saturn will be too close to the Sun in the sky on March 23rd next year. After that, the rings will open up again.
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
Ephemeris: 05/28/2024 – Finding Spica and Virgo
This is Ephemeris for Tuesday, May 28th. Today the Sun will be up for 15 hours and 15 minutes, setting at 9:18, and it will rise tomorrow at 6:01. The Moon, 2 days before last quarter, will rise at 2:06 tomorrow morning.
The Big Dipper, near the zenith at 10:30 pm points to several stars and constellations. It’s handle points to two bright stars. First we follow the arc of the handle to the bright orange star Arcturus, the 4th brightest nighttime star. The reason I say nighttime is that the Sun is a star also, but by definition is not out at night. The arc to Arcturus is a way to find Arcturus and a clue to its name. Arcturus, high in the south-southeast, lies at the base point of the kite shaped constellation of Boötes the herdsman. From Arcturus, straighten out the arc to a spike and one soon arrives at Spica a blue-white star in Virgo the virgin, now in the south. Spica is also sometimes pronounced ‘Speeka’.
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
Ephemeris: 05/27/2024 The evening sky is transitioning into summer
This is Bob Moler with Ephemeris for Memorial Day, Monday, May 27th. Today the Sun will be up for 15 hours and 14 minutes, setting at 9:17, and it will rise tomorrow at 6:02. The Moon, 3 days before last quarter, will rise at 1:36 tomorrow morning.
The sky tonight at 10:30 is beginning to show the transition from spring to summer. Antares in Scorpius is very low in the southeast, rising and chasing away Orion who has disappeared in the West. According to Greek mythology, at least in one story, Orion was killed by the sting of a giant scorpion and so neither he nor Scorpius the scorpion can be in the sky at the same time. The bright star Spica in Virgo the virgin is due South at that time, with Leo the lion in the southwest. Very high in the southeast is the star Arcturus. The Big Dipper is overhead. And in the east-northeast high up this is the bright star Vega, one of the stars of the summer triangle. The second star of the triangle Deneb is lower in the northeast. The third star has yet to rise.
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
Ephemeris: 05/24/2024 – The twilight zone
This is Ephemeris for Friday, May 24th. Today the Sun will be up for 15 hours and 9 minutes, setting at 9:14, and it will rise tomorrow at 6:04. The Moon, 1 day past full, will rise at 11:06 this evening.
Let’s take a look at twilight, despite the fact it doesn’t end until 1132 PM. Of course the bright Moon will rise before then. By the 12th of June astronomical twilight will end at midnight and a couple of days before the summer solstice it will have extended itself to 12:05 AM. The Moon tonight will rise in the middle of astronomical twilight so we’ll get about 1/2 hour or so of semi dark sky viewing from about 10:37 PM to moonrise at 11:07. There are three intervals of twilight. Civil twilight which is the period between sunset and when the Sun is 6° below the horizon. Nautical twilight extends to when the Sun is 12° below the horizon, and astronomical twilight which ends when the Sun is 18° below the horizon.
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
Ephemeris: 05/22/2024 – Where have the naked-eye planets wandered off to this week?
This is Ephemeris for Wednesday, May 22nd. Today the Sun will be up for 15 hours and 5 minutes, setting at 9:12, and it will rise tomorrow at 6:06. The Moon, 1 day before full, will set at 5:42 tomorrow morning.
Let’s find out where the naked-eye planets have wandered off to this week, and see what planets are left. Jupiter now is too close to the direction of the Sun to be seen. It is on the morning side of the Sun, and by late June may be visible in the morning sky in twilight. By 5 tomorrow morning, about 66 minutes before sunrise, Saturn will be low in the east-southeast and Mars will be lower still in the east. In telescopes, Saturn will look fairly different this year and next with its rings nearly edge on to us. They will open up a bit through October before closing again. We won’t see the rings go exactly edge on because Saturn will be too close to the Sun in the sky on March 23rd next year. After that the rings will open up again.
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
Ephemeris: 05/17/2024 – The famous Big Dipper stars Mizar and Alcor
This is Ephemeris for Friday, May 17th. Today the Sun will be up for 14 hours and 55 minutes, setting at 9:07, and it will rise tomorrow at 6:10. The Moon, 2 days past first quarter, will set at 4:01 tomorrow morning.
In tonight’s sky, the Big Dipper is nearly overhead. In its handle is a star or two that are interesting. It’s the star at the bend in the handle. It’s called Mizar. Next to it, for those with good eyesight, is a dimmer star, called Alcor. The name Mizar is from the Arabic, meaning apron or cover, while Alcor means the forgotten one. Before optometrists, the ability to actually see both stars was a test for good eyesight, especially for Arabic warriors. The pair is also known as the “Horse and the Rider”. I’ve been told that some Native American tribes saw the handle stars as hunters following the Great Bear, Ursa Major, of which the Big Dipper is a part, rather than its very unnatural tail. Dim Alcor became a hunting dog.
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
Ephemeris: 05/15/2024 – Getting reacquainted with the Moon
This is Ephemeris for Thursday, May 16th. Today the Sun will be up for 14 hours and 53 minutes, setting at 9:06, and it will rise tomorrow at 6:11. The Moon, 1 day past first quarter, will set at 3:45 tomorrow morning.
My interest in astronomy has always tended to be in deep sky, that is the part of astronomy having to do with objects beyond the solar system. This was probably mainly due to the fact that my first telescope was the reflecting telescope and not really that good at viewing the planets. My opinion of the Moon has normally been that of being a big streetlight that kept me from viewing the faint things in the sky. However, as the Apollo program was ramping up in the 1960s, I began to get more interested in the Moon. And so it is, again, now that the Artemis program is beginning to ramp up. Unfortunately the landing zones that are being planned are at the South Pole of the Moon, which we can barely see from the Earth.
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
Ephemeris: 05/15/2024 – Where have naked-eye planets wandered off to this week?
This is Ephemeris for Wednesday, May 15th. Today the Sun will be up for 14 hours and 51 minutes, setting at 9:05, and it will rise tomorrow at 6:12. The Moon, at first quarter today, will set at 3:28 tomorrow morning.
Let’s find out where the naked-eye planets have wandered off to this week, and see what planets are left. Jupiter now is too close to the direction of the Sun to be seen. It will move to be in conjunction with the Sun on Saturday and by late June may be visible in the morning sky in twilight. By 5:30 tomorrow morning, about 40 minutes before sunrise, Saturn will be low in the east-southeast and Mars will be lower still in the east. In telescopes, Saturn will look fairly different this year and next with its rings nearly edge on to us. They will open up a bit through October before closing again. We won’t see the rings go exactly edge on because Saturn will be too close to the Sun in the sky on March 23rd next year. After that the rings will open up again.
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
Ephemeris: 05/13/2024 – Viewing the Moon tonight
This is Bob Moler with Ephemeris for Monday, May 13th. Today the Sun will be up for 14 hours and 46 minutes, setting at 9:02, and it will rise tomorrow at 6:15. The Moon, 2 days before first quarter, will set at 2:44 tomorrow morning.
The crescent Moon tonight has what looks like a chain of three large craters near the terminator, visible in a low power telescope. The terminator is the line between day and night. Before the full moon, it’s the sunrise line. On closer inspection, these craters are of different ages. The north crater Theophilus, 63 miles in diameter and one of my favorite craters with a prominent central peak, looks relatively fresh. It’s not, it’s somewhat older than a billion years. The crater just south or below-left of it is Cyrillus, about the same size, which is almost 4 billion years old. Theophilus slightly overlaps Cyrillus. A bit farther south is Catharina, which again is about the same size and age range as Cyrillus, but seems more broken down than the other.
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
Ephemeris: 05/10/2024 – Earthshine
This is Ephemeris for Friday, May 10th. Today the Sun will be up for 14 hours and 39 minutes, setting at 8:59, and it will rise tomorrow at 6:18. The Moon, 3 days past new, will set at 12:37 tomorrow morning.
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 a fat waning gibbous from its vantage point. From the Moon the Earth has the opposite phase that we see of the Moon from the Earth. The effect used to be called by the term “Old moon in the new moon’s arms”. The effect was first explained by Leonardo da Vinci 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. But not many of us are up to see it 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
Bob Moler's Ephemeris Blog 