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Ephemeris: 04/16/2025 – Taking our weekly look at the naked-eye planets
This is Ephemeris for Wednesday, April 16th. Today the Sun will be up for 13 hours and 33 minutes, setting at 8:29, and it will rise tomorrow at 6:54. The Moon, halfway from full to last quarter, will rise at 12:48 tomorrow morning.
Let’s take our weekly look at the whereabouts of the naked-eye planets. At 9:30 PM this evening just two of the five naked eye planets will be out. Jupiter, now becomes the brightest evening planet, our substitute evening star if you will. It will be high in the west. Below it is the bright star Aldebaran. To its lower left, the great constellation of Orion. The rapidly fading Mars, with its distinctive reddish hue, is high in the south-southwest, with the stars Castor and Pollux in Gemini to the right of it. By 6 AM Venus will be seen very low in the east, as the Morning Star. It will require a low eastern horizon. It should be visible until a bit after 6:30. Saturn should be visible in the morning by the end of the month.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.
Addendum
Ephemeris: 04/15/2025 – Hydra the water snake spans the spring skies
This is Ephemeris for Tuesday, April 15th. Today the Sun will be up for 13 hours and 30 minutes, setting at 8:28, and it will rise tomorrow at 6:56. The Moon, 3 days past full, will rise at 11:43 this evening.
Stretching from midway up the sky in the south-southwest to low in the southeast at 10 p.m. can be found the constellation of Hydra the water snake, the longest constellation of all. Unlike the monster of the same name that Hercules slew, this Hydra has but one head, which is its most distinctive part. The head of Hydra is located between the bright stars Procyon in the southwest, which is above the brighter star Sirius low in the sky, and Regulus in Leo the lion, higher in the south. Hydra’s head is a small but distinctive group of 6 stars that make a drooping loop to the right. The rest of Hydra wends its way in a crooked line from star to star, but within a reasonably straight path down to the southeastern horizon.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.
Addendum
Ephemeris: 04/14/2025 – Follow the arc to Arcturus
This is Ephemeris for Monday, April 14th. Today the Sun will be up for 13 hours and 27 minutes, setting at 8:27, and it will rise tomorrow at 6:57. The Moon, 2 days past full, will rise at 10:36 this evening.
The fourth or fifth-brightest nighttime star, depending on whose list you see, is now up in the east in the evening. It is Arcturus, a bright star with an orange hue. It can be found otherwise by finding the Big Dipper and tracing out and extending the curve of the handle and “Follow the arc of the handle to Arcturus”, to remember the name of the star and how to find it. Arcturus is about 37 light years from us and is moving quite rapidly across the sky, compared to most stars, though one would not notice it to the naked eye in one’s lifetime. Arcturus is slightly more massive than our Sun, and about 7 billion years old, and is entering its red giant stage of life after using all the hydrogen fuel in its core. Our Sun, being slightly less massive will survive on hydrogen a bit longer.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.
Addendum
Ephemeris: 04/11/2025 – Thoughts on Starliner and Artemis problems
This is Ephemeris for Friday, April 11th. Today the Sun will be up for 13 hours and 18 minutes, setting at 8:23, and it will rise tomorrow at 7:03. The Moon, 1 day before full, will set at 6:44 tomorrow morning.
As someone who has watched the Apollo program progress, back in the 1960s, and the race to get to the Moon before the Russkies, the Artemis program seems rather sluggish. Most of the reason of course, is because it isn’t enough of a high priority, and we’re trying to do it on the cheap, reusing as much of the ill-fated space shuttle hardware as possible. NASA is gun shy about putting astronauts into danger, when they don’t have to. The Apollo 1, and two Space Shuttle accidents is the main reason that Butch and Suni didn’t ride back to Earth in their ailing Starliner capsule. The Starliner capsule is built by the same company, Boeing, who is prime contractor on the main stage of the moon rocket. Both have experienced long delays, and quality issues.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.
Addendum
Ephemeris: 04/10/2025 – Saturn is soon going to emerge from the morning twilight
This is Ephemeris for Thursday, April 10th. Today the Sun will be up for 13 hours and 15 minutes, setting at 8:22, and it will rise tomorrow at 7:04. The Moon, 2 days before full, will set at 6:29 tomorrow morning.
The planets that have transitioned from the evening sky to the morning sky are beginning to show up in the morning now as they separate themselves from the Sun. Venus is the first to appear low in the east starting about 6:00 in the morning. Saturn will be very near Venus and below right of it on the 28th of this month. Saturn will separate itself more and more from the Sun over the spring and summer months until in late September when it becomes, officially, an evening planet again. Venus will increase its separation from the Sun until May 31st, its greatest separation from the sun of 46°. Then it will slowly head back towards the direction of the Sun. However, it will stay in the morning sky for the rest of the year.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.
Addendum
On the 28th, both planets will be at the same distance west of the sun in right ascension, which is the same as longitude in the Earth’s coordinate system. The two planets were a bit closer on the 25th. Saturn is just a little bit less than three degrees above the horizon in the above image. One needs a low eastern horizon to spot it. Saturn may be visible a few days before that, however it is lacking a bright ring right now. The Earth passed through the Saturn’s ring plane on March 23rd, and we are now looking at, probably, a thin line through the planet. The ring should be fairly dim because the Sun is shining on the other side of the rings, and will until its crossover on May 6th.
Ephemeris: 04/09/2025 – Taking our weekly look at the whereabouts of the naked-eye planets
This is Ephemeris for Wednesday, April 9th. Today the Sun will be up for 13 hours and 12 minutes, setting at 8:20, and it will rise tomorrow at 7:06. The Moon, 3 days before full, will set at 6:13 tomorrow morning.
Let’s take our weekly look at the whereabouts of the naked-eye planets. At 9 PM this evening just two of the five naked eye planets will be out. Jupiter, now becomes the brightest evening planet, our substitute evening star if you will. It will be high in the west at 9 PM. Below it is the bright star Aldebaran. To its lower left, the great constellation of Orion. The rapidly fading Mars, with its distinctive reddish hue, is high in the south-southwest, in line with the stars Castor and Pollux in Gemini above right of it. By 6 AM Venus will be seen very low in the east, as the Morning Star,. It will require a low eastern horizon. It should be visible until about 6:45. Saturn should be visible in the morning by the end of the month.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.
Addendum
Ephemeris: 04/08/2025 – A look at Proxima Centauri
This is Ephemeris for Tuesday, April 8th. Today the Sun will be up for 13 hours and 9 minutes, setting at 8:19, and it will rise tomorrow at 7:08. The Moon, halfway from first quarter to full, will set at 5:57 tomorrow morning.
The nearest star to our Sun is a triple star system called Alpha Centauri or Rigil Kentaurus. It is in the skies of the Southern Hemisphere, but visible from the far southern parts of the United States. I’ve seen it from the Florida Keys and also from the latitude of the Big Island of Hawai’i. The closest member of that group this is a star we call Proxima Centauri or just Proxima for short. It is not visible to the naked eye. It is a red dwarf star maybe 12% the Sun’s mass, and at 11th magnitude. Proxima would be tough to spot with a pair of binoculars in a region of the sky which is filled with stars because it’s in the band of the Milky Way. Alpha Centauri, itself, is located near the Southern Cross, the farthest of the two bright stars to the east of it.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.
Addendum
Ephemeris: 04/07/2025 – Does the nearest star to our Sun have a habitable planet?
This is Ephemeris for Monday, April 7th. Today the Sun will be up for 13 hours and 6 minutes, setting at 8:18, and it will rise tomorrow at 7:10. The Moon, 3 days past first quarter, will set at 5:38 tomorrow morning.
The closest star to our sun is Proxima Centauri which is a small member of the Alpha Centauri star system. It is a red dwarf star and has, we think, at least three planets. They are designated b, c and d. And right now “c” is questionable. At least one of these planets is in the habitable zone of the star, based on the amount of heat this little star gives off. So these planets all quite close to the star, and the problem with Proxima and with most red dwarf stars is that they create a great number of what we call solar flares. When the Earth gets hit by a solar flare from 93 million miles it causes the Northern Lights and causes X-rays to flood the Earth which is mostly shielded by the ozone in our atmosphere. These planets are much closer to their star.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.
Addendum
Ephemeris: 04/04/2025 – GTAS Meeting tonight – Astronomy Advancement Outside the Western World
This is Ephemeris for Friday, April 4th. Today the Sun will be up for 12 hours and 57 minutes, setting at 8:14, and it will rise tomorrow at 7:15. The Moon, at first quarter today, will set at 4:12 tomorrow morning.
The Grand Traverse Astronomical Society will host its April meeting tonight at 8 PM at Northwestern Michigan College’s Joseph H Rogers Observatory. The talk for the evening will be given by Grace Kolbusz, with the student astronomy club at Northwestern Michigan College, will present the program titled Astronomy Advancement Outside the Western World. After the meeting, weather permitting, there will be viewing of the Moon and Jupiter and whatever we can find in the twilight. The observatory is located on Birmley Rd. South of Traverse City between Garfield and Keystone roads. The meeting will also be available via Zoom. Instructions to join the meeting will be on the society’s website, gtastro.org.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.
Addendum
All I know about Grace’s talk is the title. It conjures up astronomy of different cultures, perhaps those of India, China or even the Maya in Central America. In the past I have delved with my December programs, for the GTAS, into ancient astronomies of other cultures. I’ve looked at the Egyptians, Babylonians and the Greeks. And dabbled a little bit with the Mayan culture in their studies of the motions of the planet Venus. So I’m interested in what she comes up with, so I don’t overlap.
Ephemeris: 04/03/2025 – Blue Ghost’s two week long cold night
This is Ephemeris for Thursday, April 3rd. Today the Sun will be up for 12 hours and 53 minutes, setting at 8:13, and it will rise tomorrow at 7:17. The Moon, 1 day before first quarter, will set at 3:23 tomorrow morning.
During the last lunar day the Blue Ghost Lander spend its time from little after sunrise until a little after sunset investigating the surface of the Moon at the lunar Sea of Crises or Mare Crisium. It wasn’t expected to survive the two-week-long night. It wasn’t expected to because it had no internal heating and at night the temperatures on the Moon can drop to down to minus 208° F, or a little bit more on the night side. During the day the temperature gets up to 250° which is pretty hot for some of the electronics. But what really kills a Lander is at night where they can’t recharge the batteries and the batteries drop in temperature to 200° below zero for two weeks. They generally do not survive.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). Times will be different for other locations.
Addendum
Bob Moler's Ephemeris Blog 