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Ephemeris: 10/09/2025 – Eclipses and occultations of Jupiter’s satellites by each other
This is Ephemeris for Thursday, October 9th. Today the Sun will be up for 11 hours and 17 minutes, setting at 7:08, and it will rise tomorrow at 7:52. The Moon, 3 days past full, will rise at 8:16 this evening.
To astronomers the word occult doesn’t mean what you think it means. It’s not a mysterious thing, but the word occult simply means hidden, when one body hides behind another. For example, a solar eclipse isn’t really an eclipse by astronomical standards it is an occultation: the Sun hides behind the Moon. But, a lunar eclipse is really an eclipse where the Moon enters the Earth’s shadow. There is a period for the next 2½ years when Jupiter’s satellites will be both occulting and eclipsing each other. This can easily be seen in a small telescope or even binoculars. Satellites will slowly seem to merge in occultations and disappear, for some minutes, being eclipsed in another satellite’s shadow. The main show starts in May next year and ends in August 2028.
The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.
Addendum
IOTA’s website is occultations.org. Occult is free software. Besides occultations, it can be used to investigate historical and future solar and lunar eclipses, and transits of Mercury and Venus across the face of the Sun. And more.
Ephemeris: 01/13/2025 – The Moon will pass in front of Mars tonight
This is Ephemeris for Monday, January 13th. Today the Sun will be up for 9 hours and 8 minutes, setting at 5:26, and it will rise tomorrow at 8:16. The Moon, at full today, will rise at 5:00 this evening.
Tonight we will be able to witness, if it’s clear of course, an event between the Moon and the planet Mars. The Moon will pass in front of the planet Mars this evening. The event is called an occultation. If you think of tonight’s full moon as being a clock face, Mars will disappear at about the 8 o’clock position of the Moon’s edge at 9:13 PM and will reappear near the 1 o’clock position at 10:20 PM. These times should be within a minute or two depending on where you are in the listening area. However, because the full moon is so bright it will be best to view this with binoculars, starting earlier in the evening so you can find Mars against the brightness of the Moon, while it’s still far away from the Moon’s edge. Good luck, and clear skies!
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). Times will be different for other locations.
Addendum
If you are not in Northern Michigan the use of a program such as Stellarium will allow you to preview the occultation to derive the times of the ingress and egress times and positions for your location.
Ephemeris: 08/20/2024 – The Moon will pass Saturn tonight
This is Ephemeris for Tuesday, August 20th. Today the Sun will be up for 13 hours and 47 minutes, setting at 8:39, and it will rise tomorrow at 6:52. The Moon, 1 day past full, will rise at 9:25 this evening.
The bright Moon tonight will have a companion. It will be the planet Saturn, which the Moon will pass below this evening. The Moon being very bright will make it difficult to spot Saturn. So it will seem that Saturn is moving above the Moon, not the other way around. It may take a pair of binoculars to spot Saturn because it will be less than the diameter of the Moon above and to the left of the Moon early in the evening. Moving to the upper right of the Moon towards midnight. Our next full moon will be the Harvest Moon. We’re already seeing the harvest moon effect, that is the Moon rises at nearly the same time on consecutive nights, or almost so. Tomorrow’s Moon will rise only 21 minutes later than tonight’s Moon, at much less than the 50 minutes per night average.
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
Saturn will be occulted (covered up) by the Moon tonight for portions of the Earth
Ephemeris: 11/08/2023 – Where have the naked-eye planets wandered off to this week?
This is Ephemeris for Wednesday, November 8th. Today the Sun will be up for 9 hours and 52 minutes, setting at 5:22, and it will rise tomorrow at 7:31. The Moon, 3 days past last quarter, will rise at 3:26 tomorrow morning.
Let’s find out where the naked-eye planets have wandered off to this week. Three of those five planets are now visible but both Mars and Mercury set too close to sunset to be seen. So, Saturn and Jupiter are the only evening planets visible. Saturn, seen against the stars of Aquarius, can be seen in the south in the evening. Saturn will be visible till almost 1 am. Jupiter is seen rising in the eastern sky in the evening, the brightest object in the sky. In Aries this year, Jupiter will be up all night. Venus, the brilliant morning star, will rise in the east-northeast at 3:29 am. It will be seen above the waning crescent Moon. In the southeast at 7 am in the bright morning twilight.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT –5 hours). They may be different for your location.
Addendum
Ephemeris: 08/24/2023 – The Moon will pass in front of the star Antares tonight
This is Ephemeris for Thursday, August 24th. Today the Sun will be up for 13 hours and 38 minutes, setting at 8:33, and it will rise tomorrow at 6:56. The Moon, at first quarter today, will set at 12:11 tomorrow morning. | Tonight the Moon is going to pass in front of the bright reddish star in Antares in Scorpius scorpion. The event is called an occultation, and it is the only one of the monthly occultations which we’re going to be able to see in this series that began last month and will extend to August 2028. Antares will disappear at the lower left edge of the dark or night part of the Moon at approximately 10:28 pm* this evening, and it’ll stay hidden until 11:32 pm* when it will pop out on the lower right edge of the bright part of the Moon. Start looking for Antares early, probably with binoculars, because the Moon will be quite bright and might overpower Antares when viewed by the naked eye. Hoping for clear skies tonight.
*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. For other locations a planetarium computer app like Stellarium can be used to graphically predict occultation timings within a few minutes. Check your planetarium app, and set it to use Topocentric coordinates. In Stellarium, the selection is in the Configuration window, Tools tab. Check everything under Topocentric coordinates. That way the position of the Moon in the sky will be based on the chosen location, rather than the center of the Earth.
Addendum
A time-lapse prediction of the occultation of Antares by the Moon based on Stellarium imagery. In the actual occultation Antares will wink out and on suddenly. Antares is a double star, with a 5th magnitude companion. It should wink out and in 9 seconds before the main first magnitude star.
World map showing the area where the occultation of Antares can be visible. It is the area bounded by the white line, the red dotted line and the floppy figure 8 is the area where the occultation is visible. The red line shows that the area near that part of the line is where the occultation occurs during daylight the solid white line on the bottom encloses there is where the occultation will be seen at night. Michigan is close to that cyan line and so the occultation will occur near moonset. Credit: Occult 4 app.
12/07/2022 – Ephemeris – An occultation of Mars and a look at the other naked eye planets.
This is Bob Moler with Ephemeris for Wednesday, December 7th. Today the Sun will be up for 8 hours and 55 minutes, setting at 5:02, and it will rise tomorrow at 8:07. The Moon, at full today, will rise at 4:31 this evening.
Let’s see where the naked-eye planets have wandered off to this week. Mars, Jupiter and Saturn will be visible this evening, in the southeastern sky by 6 pm. At that time, Mars will be below, left of the bright full Moon. Jupiter is the brightest of the three in the southeast, while dimmer Saturn is in the south-southeast at that hour. Mars will be hidden behind the Moon from about 10:15 to 11:15 pm tonight for the IPR area. Being a full moon, Mars might be difficult to spot. It may take binoculars to spot it below, left of the Moon by 9:30, and a small telescope when Mars is near the edge of the Moon. The disappearance of Mars will be at the Moon’s 7 o’clock position, and reappearance at the 4 o’clock position. Bobmoler.wordpress.com (you are already here) has more information.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT –5 hours). They may be different for your location.
Addendum
Panoramic view of planets and Moon this evening at 7 pm tonight, December 7, 2022. Click on the image to enlarge it. Created using Stellarium.
Mars occultation animation in half hour steps for 9:15 pm, 9:45 pm, 10:15 pm (Ingress), 10:45 pm (mid-occultation), 11:15 pm (egress), 11:45 pm. The Moon and the apparent path of Mars rotates as they cross the sky from east to west. In actuality, the Moon is much brighter than Mars, so picking the planet out tonight will be a challenge. It will take the Moon almost a minute to completely cover Mars, and nearly another minute to uncover it. The plot is centered on the Moon here, but the Moon provides most of the motion here. On average, the Moon moves 12 degrees a day, while Mars moves less than a degree against the starry background. Created using Stellarium and GIMP.
Telescopic views of Saturn Jupiter and Mars (north up) as they would be seen in a small telescope, with the same magnification. The image of Mars doesn’t show it, but the white north polar cap will appear at the top or north limb of Mars. The planets are shown at 8 pm tonight, December 7, 2022. Apparent diameters: Saturn 16.25″, its rings 37.86″; Jupiter 42.55″. Mars 17.05″. Mars’ distance is 51.0 million miles (82.1 million kilometers). This is the closest it comes to the Earth this orbit. The ” symbol means seconds of arc (1/3600th of a degree.) Click on the image to enlarge it. Created using Cartes du Ciel (Sky Charts).
The naked-eye planets and the Moon at sunset and sunrise on a single night, starting with sunset on the right on December 7, 2022. The night ends on the left with sunrise on the 8th. Click on the image to enlarge it. Created using my LookingUp app and GIMP.
World map showing the area that the occultation of Mars will be visible. Occultation visibility will move from west to east. Credit: Occult version 4. This evening in the EST zone is the 8th for Universal Time (UT), or GMT (Greenwich Mean Time) if you’re older.
12/06/2022 – Ephemeris – The Moon will pass in front of Mars tomorrow night
This is Bob Moler with Ephemeris for Tuesday, December 6th. Today the Sun will be up for 8 hours and 57 minutes, setting at 5:02, and it will rise tomorrow at 8:06. The Moon, 1 day before full, will set at 7:45 tomorrow morning.
Late tomorrow evening we might get to view a really cool event, clouds permitting, when the full moon will cover or in astronomical lingo occult the planet Mars. In the Grand Traverse Region, this will occur for an hour between approximately 10:15 to 11:15 pm. The exact times depend on your location, and can vary by a minute or two over the IPR coverage area. Being a full moon, Mars might be difficult to spot. It may take binoculars to spot it below, left of the Moon by 9:30, and a small telescope when Mars is near the edge of the Moon. The disappearance of Mars will be at the Moon’s 7 o’clock position, and reappearance at the 4 o’clock position.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT –5 hours). They may be different for your location.
Addendum
Mars ingress and egress chart and times for Traverse City, MI. The times will vary by a minute or two in the IPR listening area, ingress being earlier to the west and north and later east and south. Egress times will be earlier west and later east of Traverse City. Mars takes about a minute to completely disappear and reappear again because it’s not an unresolvable point like stars.
Occultation of Mars map. The occultation of Mars by the Moon will be visible from within the bounded area. For Traverse City, MI, Mars will disappear around 10:15 pm, December 7, 2022, and reappear around 11:15 pm.
In astronomical events of solar eclipses and occultations YOU are part of the event. No, not you, but your location. Whether you see the event or not or what time the contacts (ingress, egress) happen depends on your location. And will happen for that location whether you are there, or it’s clear, or not.
12/05/2022 – Ephemeris – Mars will hide behind the full Moon Wednesday night
This is Ephemeris for Monday, December 5th. Today the Sun will be up for 8 hours and 58 minutes, setting at 5:02, and it will rise tomorrow at 8:05. The Moon, 2 days before full, will set at 6:36 tomorrow morning.
Late Wednesday night we might get to view a really cool event when the full moon will cover or in astronomical lingo occult the planet Mars. In the Grand Traverse Region, this will occur for an hour between approximately 10:15 to 11:15 pm. The exact times depend on your location, and can vary by several minutes or more. Being a full moon, Mars might be difficult to spot. I’ll have more and hopefully more accurate information tomorrow. When astronomical objects line up like this, it’s called a syzygy. This time it’s a lineup of the Sun, Earth Moon and Mars in nearly a straight line, with both the Moon and Mars in opposition from the Sun on the same night. When the Moon is in opposition, we call it a full moon instead.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT –5 hours). They may be different for your location.
Addendum
Mars ingress and egress chart and times for Traverse City, MI. The times will vary by a minute or two in the IPR listening area, ingress being earlier to the west and north and later east and south. Egress times will be earlier west and later east of Traverse City.
World map showing the area that the occultation of Mars will be visible. Occultation visibility will move from west to east. Credit: Occult version 4.
12/11/2020 – Ephemeris Extra – Venus will hide behind the Moon for W US, Canada and N Pacific Tomorrow
Tomorrow Saturday, December 12, 2020 Venus will be occulted, or covered, by the thin crescent Moon for the area bounded in the map below. The southern boundary is a thin red line denoting that the event will take place in daylight. For safety sake observe the event from the shadow of a building open to the sky west of the Sun to not inadvertently point binoculars or telescope toward the Sun and cause permanent damage to your eyes. Venus is visible in the daytime. A program like Stellarium will help in locating Venus and determination of the time of the event for your location. Also, for Stellarium, in the configuration window’s Tool tab make sure “Topocentric coordinates” is checked.
The event will NOT be visible from Michigan.
Occultation of Venus World map 12/12/2020. The occultation will be visible within the bounded area. For the area that looks like a lazy figure 8 the occultation will start (on the left) or end as Venus and the Moon rises or sets. For most areas within the bounded area the occultation is a daytime event. Credit Occult4.
02/17/2020 – Ephemeris Extra – The Moon will cover the planet Mars in morning twilight tomorrow, Tuesday the 18th.
Sorry, I missed this until now. Tomorrow morning the 18th Mars will be occulted by the Moon. For Northern Lower Michigan Mars will disappear shortly after 7:10 a.m. The exact time depends on your location, so I can’t be more specific. At that time the Moon and Mars will be in the southeastern sky. Mars is now first magnitude, but will fare poorly in the morning twilight, so I’d suggest finding the Moon and Mars at least 15 minutes earlier with binoculars or telescope. Mars will reappear at the Moon’s unlit side around 8:37 a.m. This is after sunrise, so a telescope will be required to spot it. Hoping for clear skies, though the weather forecast isn’t promising.
A map of where the occultation of Mars will be visible. Created using Occult4.
Where Mars will disappear at the Moon’s sunlit edge. Created using Stellarium.
Mars will reappear at the Moon’s unlit edge around 8:36 a.m. give or take. Created using Stellarium.
Bob Moler's Ephemeris Blog 