Archive
04/14/2016 – Ephemeris – It’s always a cloudy day on Jupiter, worse than Traverse City in winter.
Ephemeris for Thursday, April 14th. The Sun will rise at 6:59. It’ll be up for 13 hours and 27 minutes, setting at 8:27. The Moon, 1 day past first quarter, will set at 3:50 tomorrow morning.
If one has a large enough telescope, possibly 100 millimeters diameter or larger Jupiter’s cloud detail can be studied. At first appearance the clouds appear simple light and dark stripes. They are caused by Jupiter’s rapid rotation of a bit less than 10 hours. The dark stripes are called belts. The darkest and broadest of these is the North Equatorial Belt. The next darkest belt is the South Equatorial Belt, which actually disappeared for a time in 2010. On the belt’s south side is found the Great Red Spot an anticyclone. The white stripes are called zones. There are more belts and zones at higher latitudes. The Great Red Spot is kinda pink now. In my youth in the 1950s it could be easily spotted in a small telescope and it was brick-red!
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Scott Anttila image of Jupiter from November 14, 2011.
Note how faded the Great Red Spot was.
04/13/2016 – Ephemeris – What’s up with the bright planets this week?
Ephemeris for Wednesday, April 13th. The Sun will rise at 7:01. It’ll be up for 13 hours and 24 minutes, setting at 8:26. The Moon, at first quarter today, will set at 3:09 tomorrow morning.
Let’s see what the bright naked eye planets are up to. Mercury is in the west-northwest, very low to the horizon, setting at 10:12 p.m. The next 7 days will be the best time to spot it. Jupiter is in the southeast in the evening, and will pass due south at 11:15 p.m., and will set at 5:48 a.m. It’s below the stars of Leo this year. Binoculars can make out some of Jupiter’s moons, but a telescope is required to see all four bright moons and Jupiter’s cloud features. Mars will rise at 12:08 a.m. in the east-southeast. It’s above Scorpius but is actually in western Ophiuchus now. Saturn will rise at 12:38 a.m. in the east-southeast. It’s just left of Mars. Its rings are a telescopic treat. Venus will rise at 6:37 a.m. and not really visible in the bright twilight.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Mercury at 9 p.m. April 13, 2016. At this time Mercury will be located at 284° azimuth and 11.5° altitude. Created using Stellarium.
Jupiter, the Moon and the constellations visible at 10 p.m. April 13, 2016.. Created using Stellarium.
Jupiter and its moons at 10 p.m. April 13, 2016. Jupiter has an apparent diameter of 42.7″ Created using Cartes du Ciel (Sky Charts).
The Moon as it would appear tonight at 9 p.m. April 13, 2016. Created using Virtual Moon Atlas.
Mars and Saturn with a preview of the summer constellations at 6 a.m., April 14, 2016. Created using Stellarium.
Saturn and its moons at 6 a.m., April 14, 2016. Saturn’s apparent diameter is 17.7″ and the rings span 41.3″ Created using Cartes du Ciel (Sky Charts).
Mars as seen in a large telescope with high power at 6 a.m., April 14 2016. Mars apparent diameter 13.5″. The central meridian will be 202° Created using Cartes du Ciel (Sky Charts).
Mars map – North up.
Planets at Sunrise and Sunset on April 13, 2016. If you are using Firefox right-click on the image and select View Image to enlarge the image.
04/12/2016 – Ephemeris – Can you tell the Jovian moons apart without a program?
Ephemeris for Yuri’s Night, Tuesday, April 12th. The Sun will rise at 7:02. It’ll be up for 13 hours and 21 minutes, setting at 8:24. The Moon, 1 day before first quarter, will set at 2:22 tomorrow morning.
It’s the 55th anniversary of Yuri Gagarin’s flight as first human to orbit the Earth. Speaking of orbits, we can see Jupiter’s 4 largest moons orbit that planet in small telescopes. Their orbits are nearly edge on to us, so they seem to move back and forth from one side to the other of the planet in pretty much a straight line. So how can you tell them apart without a reference? The four moons from Jupiter in order are Io, Europa, Ganymede, and Callisto. They are not normally arranged like that. Ganymede is the brightest and Callisto the dimmest, and is usually the farthest away. Io is usually the closest appearing and has a slight reddish hue due to its sulfurous volcanic surface, and Europa is the dimmer moon close in to Jupiter. Io also can be seen to noticeably move in an hour.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
One of my old pictures of Jupiter. Callisto is obvious from its far left position and dimmer brightness. On the right, the farthest is Ganymede due to its brightness and position. Inside of it is Europa, again, dimmer than Ganymede and inside position is probably Europa. That leaves Io, which may be trying to duck behind Jupiter, as a bump in the left edge of the planet.
Jupiter and its moons as simulated by Cartes du Ciel for tonight, 10 p.m. April 12, 2016. The bodies, from let to right are Ganymede, Callisto. a background star, Jupiter, Io, and Europa.
04/11/2016 – Ephemeris – The margins of the Moon
Ephemeris for Monday, April 11th. The Sun will rise at 7:04. It’ll be up for 13 hours and 18 minutes, setting at 8:23. The Moon, 2 days before first quarter, will set at 1:28 tomorrow morning.
Lets check out the Moon tonight. The Moon’s terminator, now the sunrise line traversing the Moon is beginning to uncover the dark Mare Tranquillitatis or Sea if Tranquility on the equator of the Moon. The small round prominent sea on the right side of the Moon is Mare Crisium, or Sea of Crises. At the limb beyond Crisium is Mare Marginis or sea at the Margin, and below it also at the edge is Mare Smythii, or Smith’s Sea, named after William Henry Smith a 19th century British astronomer. These last two seas are only visible when the Moon appears to rock to the left and reveals them. This is called libration caused by the fact the Moon rotates at a constant rate and it orbits the Earth in an ellipse, changing it’s speed.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Map of the Moon for April 11, 2016. The arrow shows the point of maximum libration for that date. Created using Virtual Moon Atlas.
Photo of the receding Moon taken by the Crew of Apollo 8 as they started to head home showing the near side on the left and the far side on the right. I’ve annotated the seas which I’ve described above. Credit NASA.
04/08/2016 – Ephemeris – Daytime occultation of Aldebaran Sunday the 10th
Apr 8. This is Bob Moler with Ephemeris for Friday, April 8th. The Sun will rise at 7:09. It’ll be up for 13 hours and 9 minutes, setting at 8:19. The Moon, 1 day past new, will set at 10:03 this evening.
The Moon will pass in front of the bright star Aldebaran Sunday evening. However it will still be daylight out. So this will be a challenge for the observer with binoculars, or better yet, telescope. The moon will appear as a washed out crescent in the blue sky. It will require an exceptionally clear sky to see Aldebaran, which once the Sun sets will appear just below the Moon and is part of the Face of Taurus the bull. For the IPR listening area Aldebaran will disappear at the Moon’s dark upper left edge at 6:29 p.m. plus or minus a minute, depending on your location. The star will reappear at 7:38 p.m., give or take a minute, on the right edge of the Moon, just below the dark oval of the Sea of Crises. This is second of 4 Aldebaran occultations visible from here this year.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Ingress: 6:29 p.m.
Aldebaran ingress at approximately 6:29 p.m. April 10, 2016. Created using Stellarium.
Egress: 7:38 p.m.
Aldebaran egress at approximately 7:38 p.m. April 10, 2016. Created using Stellarium.
Occultation Visibility Map
Occultation Map for Aldebaran. Bright outline of occultation path is where it occurs at night. Credit IOTA program Occult 4.
Aldebaran will most likely need a telescope to spot once the Moon is located. The representations above via Stellarium will show the star as being too bright. It will be quite dim in relation to the sky brightness. The Moon too will be washed out. Start searching before the occultation start to make sure the star can be located. Even a little haze will make seeing the event impossible.
The actual time of the ingress and egress will vary by several minutes depending on your location in Michigan. Stellarium or other planetarium programs can be used to predict the timings to within a minute. IOTA the http://www.lunar-occultations.com/iota/iotandx.htm has a free Windows program Occult 4 which will give accurate occultation and transit of Mercury predictions.
04/07/2016 – Ephemeris – The Big Dipper, the Great Bear and the Fisher Star
Ephemeris for Thursday, April 7th. The Sun will rise at 7:11. It’ll be up for 13 hours and 6 minutes, setting at 8:18. The Moon is new today, and won’t be visible.
The constellation of Ursa Major, or great bear was well-known to the ancient Greeks and Native Americans. Today, however, many of us can recognize only part of it as the Big Dipper. The bear can be easily seen only in a dark sky, at 10 p.m. it’s high just north of the zenith with feet to the south. The stars in front of the bowl are the front part of his body and head. The bowl of the Big Dipper is his rump, and the handle his long tail. The Native Americans, saw those three stars as three hunters following the bear. The tribes of the Great Lakes region saw it as the Fisher Star, who brought summer to the Earth. These stars here do make a convincing bear, except for the tail, when seen on a dark night. The weasel-like Fisher Star fits the stars completely.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Animation of 4 views of Ursa Major. 1. with no added imagery, emphasizing the Big Dipper, 2. added lines for Ursa Major, 3. image of the bear, 4. image of Fisher Star. Created using Stellarium and GIMP.
Note: The Fisher Star illustration is an unattributed drawing from the Internet with a minor change.
04/06/2016 – Ephemeris – Mercury makes its spring appearance in the west – Plus Jovian moon hijinx
Ephemeris for Wednesday, April 6th. The Sun will rise at 7:13. It’ll be up for 13 hours and 3 minutes, setting at 8:17. The Moon, 1 day before new, will rise at 7:30 tomorrow morning.
Let’s check out the whereabouts of the bright naked eye planets. Mercury is in the west-northwest, very low to the horizon, setting at 9:35 p.m. Jupiter is in the southeast in the evening, and will pass due south, astronomers call it a transit, at 11:45 p.m., and will set at 6:16 a.m. It’s below the stars of Leo this year. Binoculars can make out some of Jupiter’s moons, but a telescope is required to see all four bright moons and Jupiter’s cloud formations. Mars will rise next at 12:31 a.m. in the east-southeast. It’s above Scorpius but moved into western Ophiuchus now. Saturn will rise at 1:06 a.m. in the east-southeast. It’s just left of Mars. Its rings are a telescopic treat. Venus will rise at 6:47 a.m. due east.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Evening sky
Mercury appears low in the sky in the west at 8:40 p.m. April 6, 2016. Created using Stellarium.
An animation of Jupiter in the night sky with and without lines and captions at 10 p.m., April 6, 2016. Created using Stellarium and GIMP.
If you are using Firefox right-click on the image and select View image to enlarge.
Jupiter and its moons at 10 p.m. April 6, 2016. It’s going to be busy night with the three closest moons playing tag with Jupiter. See the table of events below. Jupiter appears 43.2″ in diameter. Created with Cartes du Ciel (Sky Charts).
Jovian satellite events overnight
Io and Ganymede will pass in front (transit) the face of Jupiter, while Europa pass behind and be occulted by Jupiter.
| Event | Date/Time EDT | Date/Time UT | ||
| Io Transit Starts | 6 | 9:52 p.m. | 7 | 01:52 |
| Io Shadow Crossing Starts | 6 | 10:30 p.m. | 7 | 02:32 |
| Europa Occultation Starts | 6 | 10:48 p.m. | 7 | 02:48 |
| Io Transit Ends | 7 | 12:06 a.m. | 7 | 04:06 |
| Io Shadow Crossing Ends | 7 | 12:47 a.m. | 7 | 04:47 |
| Ganymede Transit Starts | 7 | 1:00 a.m. | 7 | 05:00 |
| Europa Eclipse Ends* | 7 | 2:53 a.m. | 7 | 06:53 |
| Ganymede Shadow Crossing Starts | 7 | 3:44 a.m. | 7 | 07:44 |
| Ganymede Transit Ends | 7 | 4:15 a.m. | 7 | 08:15 |
| Ganymede Shadow Crossing Ends | 7 | Not up | 7 | 11:00 |
| * When Europa’s occultation ends it will still be in Jupiter’s shadow and will enter sunlight a bit away from the planet. | ||||
Timings are from Project Pluto.
Morning sky
Looking south at 6 a.m. at Mars and Saturn in an animation with and without annotations. 6 a.m. April 7, 2017. Created using Stellarium and GIMP.
Mars as seen in a large telescope with high power at 6 a.m., April 7, 2016. Mars apparent diameter 12.7″. Created using Cartes du Ciel (Sky Charts).
Saturn with some of its satellites. Normally only Titan is visible. The disk of Saturn has the apparent diameter of 17.6″ while the rings span 40.9″. Created using Cartes du Ciel (Sky Charts).
The planets at sunrise and sunset
This is a chart showing the sunrise and sunset skies for April 6, 2016 showing the location of the planets and the Moon at that time. Created using my LookingUp program.
04/05/2016 – Ephemeris – Coma Berenices, the second closest star cluster
Ephemeris for Tuesday, April 5th. The Sun will rise at 7:15. It’ll be up for 13 hours and 1 minute, setting at 8:16. The Moon, 2 days before new, will rise at 6:53 tomorrow morning.
Midway up the sky in the east at 10 p.m. is a tiny sprinkle of faint stars arrayed to look like several strands of hair. It’s the constellation of Coma Berenices, or Berenice’s hair. The whole group will fit in the field of a pair of binoculars, which is the best way to see it, and will also show more stars. The cluster contains about 50 stars and lies at a distance of 280 light years from us, which makes it the second closest star cluster. The closest being the Hyades, that is the face of Taurus the bull now about to set in the west. The star cluster appears to be about 480 million years old. It is an open or galactic star cluster, born along the plane of the Milky Way. It appears away from the milky band due to its proximity to us.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Coma Berenices finder chart 10 p.m., April 5, 2016. Created using Stellarium.
Coma Berenices as it might look in a pair of binoculars. Telescopes are too powerful. Created using Stellarium.
04/04/2016 – Ephemeris – Hydra the water snake will slither along the southern horizon this spring
Ephemeris for Monday, April 4th. The Sun will rise at 7:17. It’ll be up for 12 hours and 57 minutes, setting at 8:14. The Moon, 3 days before new, will rise at 6:18 tomorrow morning.
In the southeastern evening sky can be found the constellation of Hydra the water snake. Unlike the monster of the same name this Hydra has but one head, which is its most distinctive part. At 10 p.m. look to the south-southeast. The head of Hydra is located below a line from the constellation Leo the Lion in the southeast and Gemini high in the southwest. It is directly below Cancer the crab in the south. Hydra’s head is a small but distinctive group of 6 stars that make a loop and the snake’s slightly drooping head. The rest of Hydra wends its way to the southeastern horizon, and eventually ends near the late spring constellation Libra the scales. Over the next few months the rest of Hydra will slither across the southern horizon.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Hydra the water snake raising its head below Cancer at 10 p.m. April 4, 2016. Created using Stellarium.
04/01/2016 – Ephemeris – Let’s preview April skies
Ephemeris for April Fools Day, Friday, April 1st. The Sun will rise at 7:22. It’ll be up for 12 hours and 48 minutes, setting at 8:11. The Moon, 1 day past last quarter, will rise at 4:23 tomorrow morning.
The 4th month of the year begins today. Daylight hours in the Interlochen/Traverse City area and will increase from 12 hours and 48 minutes today to 14 hours 13 minutes on the 30th. The altitude, or angle, of the sun above the southern horizon at local noon will be 50 degrees today and will ascend to 60 degrees on the 30th. The altitude of the sun in the Straits area will be a degree lower. The actual time of local apparent noon this month for the Interlochen/Traverse City area, when the sun passes due south, will be about 1:43 p.m. Jupiter and Mercury are the evening planets this month, with Mercury making its brief appearance away from the Sun’s sunset glow around mid-month.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
April Star Chart
Star Chart for April 2016. Created using my LookingUp program. To enlarge in Firefox Right-click on image then click View image.
Star Chart for April 2016. Created using my LookingUp program. To enlarge in Firefox Right-click on image then click View image.
The planets and stars are plotted for the 15th at 10 p.m. EDT. That is chart time. Note, Traverse City is located approximately 45 minutes behind our time meridian. (An hour 45 minutes behind our daylight saving time meridian.) To duplicate the star positions on a planisphere you may have to set it to 1:45 earlier than the current time.
Evening nautical twilight ends at 9:15 p.m. EDT on the 1st, increasing to 9:59 p.m. EDT on the 30th.
Morning nautical twilight starts at 5:21 a.m. EDT on the 1st, and decreasing to 4:37 a.m. EDT on the 31st.
Add a half hour to the chart time every week before the 15th and subtract a half hour for every week after the 15th. Before the 13th also subtract an hour for Standard Time.
For a list of constellation names to go with the abbreviations click here.
- Pointer stars at the front of the bowl of the Big Dipper point to Polaris the North Star
- A leaky Big Dipper drips on Leo
- Follow the arc of the handle of the Big Dipper to the star Arcturus
- Extend the ac to a spike to point to Spica
Calendar of Planetary Events
Credit: Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA’s GSFC)
To generate your own calendar go to http://eclipse.gsfc.nasa.gov/SKYCAL/SKYCAL.html
Times are Eastern Time. Some additions made to aid clarity.
Date Time(EDT) Event Apr 01 Fr Venus: 17.4° W 05 Tu 1:27 p.m. Moon Descending Node 06 We 4:30 a.m. Moon-Venus: 0.7° S 07 Th 7:24 a.m. New Moon 07 Th 1:36 p.m. Moon Perigee: 357200 km 09 Sa 5:28 p.m. Uranus Conjunction 10 Su 6:05 p.m. Moon-Aldebaran: 0.4° S Occultation* 12 Tu 8:12 a.m. Moon North Dec.: 18.3° N 13 We 11:59 p.m. First Quarter 16 Sa 8:46 p.m. Moon-Regulus: 2.7° N 18 Mo 12:42 a.m. Moon-Jupiter: 2.4° N 18 Mo 9:59 a.m. Mercury Elongation: 19.9° E 18 Mo 2:04 a.m. Moon Ascending Node 21 Th 12:05 p.m. Moon Apogee: 406400 km 22 Fr 1:24 a.m. Full Moon 22 Fr 1:30 a.m. Lyrid Shower: ZHR = 20 25 Mo 3:28 p.m. Moon-Saturn: 3.7° S 27 We 12:44 a.m. Moon South Dec.: 18.4° S 27 We 12:33 p.m. Mars-Antares: 4.9° N 28 Th 4:32 a.m. Mercury-Pleiades: 6.5° S 29 Fr 11:29 p.m. Last Quarter May 01 Su Venus: 9.8° W * Occultation 6:29 - 7:38 p.m. In daylight - Grand Traverse Area See Friday April 9th post.
Bob Moler's Ephemeris Blog 