Archive
01/17/2014 – Ephemeris – The Moon tonight
Ephemeris for Friday, January 17th. The sun will rise at 8:14. It’ll be up for 9 hours and 16 minutes, setting at 5:30. The moon, 2 days past full, will rise at 7:23 this evening. | Let’s take a look at the moon as it’s still dominates the evening sky. The terminator, now that it’s after full moon is the sunset line. It is just starting to encroach on the small distinctive sea at the moon’s upper right edge called the Sea of Crises or Mare Crisium. Where is is situated on the edge of the spherical moon it appears to be elongated north to south. However if you saw it from overhead it would actually be elongated somewhat east to west. On the terminator at the moon’s equator is a large crater called Langrenus with a central peak on the edge of the Sea of Fertility or Mare Fecunditatis, that should be an easy binocular and a great telescopic crater some 80 miles in diameter. The smallest ting you can see on the moon in a small telescope is 2 miles in diameter.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Moon at 9 p.m., January 17, 2014. Created using Virtual Moon Atlas.
Mare Crisium as seen from overhead at 9 p.m., January 17, 2014. Created using Virtual Moon Atlas.
This last image cannot be seen without a spacecraft. The image was created using data from the Clementine spacecraft.
01/16/2014 – Ephemeris – NASA/JPL Solar System Ambassador
Ephemeris for Thursday, January 16th. The sun will rise at 8:15. It’ll be up for 9 hours and 14 minutes, setting at 5:29. The moon, 1 day past full, will rise at 6:25 this evening.
I am proud to announce that I have been appointed one of the NASA Jet Propulsion Laboratory’s new 38 new Solar System Ambassadors for 2014. Solar System Ambassadors are volunteers that host star parties, and provide presentations about space, the universe, and NASA missions to promote awareness of the STEM or Science, Technology, Engineering and Math fields as career choices or at least to encourage the students to become more science literate voters. Ambassadors work with school classes, scout groups and non-profit organizations. Being now newly retired I have the freedom of daytime visits. I will be serving the northwestern Lower Peninsula of Michigan. Interested? The easiest way to initially contact me by email is at info@gtastro.org or bob@bjmoler.org.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
01/15/14 – Ephemeris – Where are the bright planets this week?
Ephemeris for Wednesday, January 15th. The sun will rise at 8:15. It’ll be up for 9 hours and 12 minutes, setting at 5:28. The moon, at full today, will rise at 5:28 this evening.
Let’s take our weekly look at the planets. The giant planet Jupiter is now alone in the evening sky. It will be in the eastern sky as darkness falls tonight. It’s cruising against the stars of Gemini now. It will pass due south at 12:05 a.m., and will set at 7:42 a.m. in the west northwest. Mars will rise at 12:28 a.m. in the east. Reddish Mars is in Virgo now and to the upper right of the bright star Spica by the three-quarters of the width of your fist held at arm’s length. Saturn will rise at 3:26 a.m. in the east southeast. It’s seen against Libra the scales this year. Venus will rise at 7:18 tomorrow morning, so it may become visible around 7:45 or so very low in the east southeast. It’s sudden appearance has caused come airport tower controllers to give it permission to land.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Jupiter, the Moon with the winter stars at 9 p.m. on January 15, 2014. Created using Stellarium.
The telescopic Jupiter at 9 p.m. and January 15, 2014. The moon Europa is in front or transiting Jupiter. Created using Stellarium.
Europa, the smallest of the four Galilean satellites of Jupiter will transit the face of Jupiter tonight. It’s shadow will also cross that planet. The transit starts at 9:02 p.m. Stellarium is slightly off in that regard. Cartes du Ceil is better in that regard. Europa’s shadow starts to cross Jupiter at 9:33 p.m. Europa’s transit ends at 11:43 p.m., while it’s shadow leaves the face of Jupiter at 12:16 a.m. The source for these times is Project Pluto’s Jupiter Satellite Events page.
Mars and Saturn with the spring stars at 6:30 a.m. on January 16, 2014. Created using Stellarium.
For the adventurous, Venus at 7:45 a.m. tomorrow morning January 16, 2014. Created using Stellarium.
Venus as it might appear in a telescope at 7:45 a.m. tomorrow morning January 16, 2014. You will not see its night side, just the crescent. Created using Stellarium.
Want to see Venus closer to inferior conjunction? Check out Universe Today’s Virtual Star Party for January 12, 2014.
01/14/2014 – Ephemeris – The moon will appear to pass Jupiter tonight
Ephemeris for Tuesday, January 14th. The sun will rise at 8:16. It’ll be up for 9 hours and 10 minutes, setting at 5:27. The moon, 1 day before full, will set at 7:29 tomorrow morning.
The planet Jupiter will appear close to the nearly full moon this evening. The moon will pass about 10 of its diameters south of Jupiter around 1 a.m. tomorrow morning. Until then, Jupiter will appear to the left of the moon. This is a good time to view Jupiter with a small telescope. Even binoculars will detect a tiny disk and several of Jupiter’s satellites. Jupiter is a gas giant planet made primarily of hydrogen. The clouds contain methane and ammonia whipped into parallel bands by Jupiter’s rapid rotation of nearly 10 hours. The planet has a noticeable equatorial bulge, which is accentuated visually by its horizontal cloud bands. Jupiter’s equatorial diameter is 89,000 miles [143,000 km], 11 times that of the earth. [Jupiter’s volume could hold about 1,300 Earths, but its mass is only about 318 Earths. Jupiter is less dense than the Earth by a factor of four.]
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
[Content in brackets was not included in the broadcast program due to time constraints.]
Jupiter, the Moon and the bright stars of winter at 9 p.m. on January 14, 2014. By 1 a.m. the Moon will have slipped to be directly below Jupiter. The Moon moves about its own diameter against the stars each hour. Created using Stellarium.
Jupiter as seen by the Cassini spacecraft as it passed by Jupiter gaining velocity on its way to Saturn. The black dot is the shadow of Europa. Credit: NASA/JPL – Caltech.
01/13/2014 – Ephemeris – Jupiter’s Great Red Spot
Ephemeris for Monday, January 13th. The sun will rise at 8:16. It’ll be up for 9 hours and 9 minutes, setting at 5:25. The moon, 2 days before full, will set at 6:49 tomorrow morning.
Jupiter is my youngest granddaughter’s favorite planet. She has books and pictures of Jupiter sporting its famous Great Red Spot. When I was a teenager in the 1950s, a bit older than she is now the Great Red Spot on Jupiter was indeed bright red. You couldn’t miss it in even the smallest telescopes. Since the early 1970s the spot has faded. At best it’s a pastel pink. The Great Red Spot appears to be a permanent feature of the Jovian atmosphere, an anti-cyclone that distorts the dark belts and bright zones of the planet. The dark belts are thought to be where air is sinking and the white zones are upwelling clouds. The Great Red Spot wanders east and west at about the same latitude within the atmosphere. I hope it gets really red soon.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Jupiter with its Great Red Spot November 18, 2012 by Scott Anttila.
01/10/2014 – Ephemeris – Venus will pass inferior conjunction with the sun tomorrow.
Ephemeris for Friday, January 10th. The sun will rise at 8:18. It’ll be up for 9 hours and 4 minutes, setting at 5:22. The moon, 3 days past first quarter, will set at 4:19 tomorrow morning.
Tomorrow what has been our evening star during summer an autumn will pass between the Earth and the Sun and will enter the morning sky, where sharp-eyed observers will pick it up just before sunrise. That passage is called inferior conjunction, because Venus moves between the Earth and the Sun. Venus and Mercury are called inferior planets, not because of their quality, but because they orbit inside the earth’s orbit. Mars through Neptune are then of course superior planets. The last time Venus passed inferior conjunction, on June 5th, 2012 it passed directly in front of the sun in a rare transit. This time it will be north of the sun by about 5 angular degrees. There’s only a hundred and four years before the next transit.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Gary Carlisle’s photo of the transit of Venus, June 5, 2012..
01/09/2014 – Ephemeris – More on Jupiter’s Galilean moons.
Ephemeris for Thursday, January 9th. The sun will rise at 8:18. It’ll be up for 9 hours and 3 minutes, setting at 5:21. The moon, 2 days past first quarter, will set at 3:20 tomorrow morning.
The planet Jupiter has, as of the latest count, 67 satellites or moons. However only four can be seen in small to medium-sized telescopes. Astronomers use the term moon and satellite interchangeably, though only moons orbit planets. A satellite is a more generic term and is a smaller body that orbits another larger body. Though we don’t usually call an artificial satellite orbiting the Earth a moon. Anyway, the four bright moons of Jupiter are called the Galilean moons, because Galileo discovered then in early 1610. Their names from Jupiter on out are Io, Europa, Ganymede and Callisto. They orbit over Jupiter’s equator. Since the planet has a very small axial tilt the moons seem to move back and forth from one side to the other of Jupiter in a nearly straight line.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Jupiter and its four Galilean moons. The planet has to be over exposed to pick up the moons. But the eye can handle the brightness difference with no problem. This is one of my old pictures I do believe.
Jupiter with a solar eclipse in progress as Ganymede, lower left, casts its shadow on Jupiter on November 14, 2011 at about 10:15 p.m.. Credit: Scott Anttila.
The moon Io is off to the far left. This eclipse can be simulated with Cartes du Ciel.
01/08/2014 – Ephemeris – Where are the bright planets this week?
Ephemeris for Wednesday, January 8th. The sun will rise at 8:18. It’ll be up for 9 hours and 2 minutes, setting at 5:20. The moon, 1 day past first quarter, will set at 2:18 tomorrow morning.
This is our weekly look at the planets. Venus is only three days from passing between the Earth and the Sun in what astronomers call inferior conjunction. Sharp eyed observers may be able to spot it in the bright twilight glow before it sets at 5:57 p.m. tonight. It will then pass into the morning sky. The giant planet Jupiter will be in the eastern sky as darkness falls tonight. It’s cruising against the stars of Gemini now. It will pass due south at 12:32 a.m., and will set at 8:13 a.m. Mars will rise at 12:39 a.m. in the east. Reddish Mars is in Virgo now and to the upper right of the bright star Spica by the width of your fist held at arm’s length. Saturn will rise at 3:47 a.m. in the east southeast. It’s seen against Libra the scales this year.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
For diehards, Venus 15 minutes before it will set tonight January 8, 2014.
Venus at 3 days before inferior conjunction back in the late 1960’s. My photograph.
Jupiter, the Moon with the winter constellations at 9 p.m. on January 8, 2014. Created using Stellarium.
The telescopic moon at 9 p.m. January 8, 2014. Created using Stellarium.
The telescopic Jupiter at 9 p.m. and January 8, 2014. The label for the moon Europa overlaps that of Jupiter. Created using Stellarium.
Mars and Saturn with the spring constellations at 6:30 a.m. on January 9, 2014. Created using Stellarium.
01/07/2014 – Ephemeris – Jupiter just after opposition
Ephemeris for Tuesday, January 7th. The sun will rise at 8:18. It’ll be up for 9 hours and 1 minute, setting at 5:19. The moon, at first quarter today, will set at 1:14 tomorrow morning.
The giant planet Jupiter was in opposition from the Sun two days ago, meaning that the Sun, Earth and Jupiter were pretty much in a line. It was a time the Jupiter was closest to us. The situation hasn’t changed much, However you will notice that tomorrow I will not give the time that Jupiter rises because it will rise before sunset, but I will give its setting time. Now Jupiter is about 391 million miles (630 million km) away and slowly dropping behind the faster moving Earth. Jupiter is so large that there is never bad time to view it with a small telescope, but Jupiter appears largest right now. Visible in telescopes are its four moons that change position from night to night. The face of the planet shows atmospheric cloud bands that bear closer scrutiny with larger telescopes.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Jupiter and its four Galilean moons. The planet has to be over exposed to pick up the moons. The bump on the upper left of Jupiter’s image is another moon. But the eye can handle the brightness difference with no problem. This is one of my old pictures I do believe.
Jupiter by Scott Anttila. Taken February 6, 2012
01/06/2014 – Ephemeris – It will be a year of eclipses for northern Michigan!
Ephemeris for Monday, January 6th. The sun will rise at 8:19. It’ll be up for 8 hours and 58 minutes, setting at 5:18. The moon, 1 day before first quarter, will set at 12:07 tomorrow morning.
The year 2014 will be a year of eclipses. World wide it will have the minimal number of eclipses possible, four. However, lucky us, we will see three of them if it’s clear, that is. The first is a total eclipse of the moon in the wee morning of Tax Day, April 15th. It will be the best of the three because we will see it from beginning to end. On October 8th we will have another lunar eclipse is the morning. This one will start closer to dawn, so the kids can see this one by getting up early. The total phase will be visible, but the moon will set as the moon is leaving the earth’s shadow. The last will be a partial solar eclipse on October 23rd. when the eclipse will be interrupted by sunset.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
My Article in January’s Stellar Sentinel, the newsletter of the Grand Traverse Astronomical Society.
After a drought in visible eclipses seen from our part of the planet last year and a single partial solar eclipse the year before, we have a chance, weather permitting, to view two total lunar eclipses and the first half of a partial solar eclipse this year. OK, we did have a penumbral lunar eclipse last year, but I usually don’t count penumbral eclipses, since the casual observer may look at the moon and not know they are occurring. They’re what I call a 5 o’clock shadow eclipse, where parts of the moon are illuminated by a partially blocked sun. There is no obvious dragon or Cookie Monster nibbling at the moon.
Eclipse Seasons
In 2014 the two eclipse seasons are in April and again in October. These are about six months apart centered around the moon’s ascending and descending nodes, where the plane of the Moon’s orbit crosses the Earth’s orbital plane when the new moon’s shadow can fall upon the earth and the earth’s shadow can fall on the full moon.
The line of nodes regresses westward or clockwise slowly in an 18.6 year period. That means that the eclipse seasons slowly move backward through the calendar. Every time the sun passes a node there are either two or rarely, three eclipses. Either one each of lunar and solar separated by two weeks from the other. Or, rarely, a central eclipse with 2 weeks before and two weeks later a very partial eclipse near the poles in the case of solar eclipses or penumbral eclipses in the case of lunar eclipses. 2014 is a year of two total lunar eclipses and two partial solar eclipses near the poles.
Saros
A means of predicting eclipses was developed by the Chaldeans in what is now Iraq some centuries before the common era (BC or BCE). The Greeks learned of it. Hipparchus and Ptolemy knew of it. Solar and lunar eclipses repeat every 18 years 11 1/3 days. This cycle was called the Saros by Sir Edmund Halley of Halley’s Comet fame, then Astronomer Royal in England.
The saros is the near coincidence of 3 lunar “months”: the Synodic Month, or lunation the period between new moons; the Draconic Month, the period between the moon’s passage of the ascending node of its orbit as explained above; and the Anomalistic Month, the period between passages of the moon through perigee, the closest point in its orbit to the earth.
The synodic month is on average 29.530589 days, and the basis for the Jewish and Islamic lunar calendars.
The draconic month is 27.212220 days long on average. The ascending node regresses westward, so meets the moon, traveling eastward than the synodic month, where it has to catch up with the eastward moving sun. Remember the dragon eating the sun image from above. The ancients thought a dragon lived at the nodes to devour the Sun or Moon in eclipses. The symbol for the ascending node:
is called the Dragon’s Head. For the descending node the symbol is inverted and called the Dragon’s Tail. These symbols may be seen on orbital diagrams.
The anomalistic month is 27.554551 days. In celestial mechanics an anomaly doesn’t means anything is wrong, it’s the angle between, in the case of the moon, the perigee of its orbit and the position of the moon as seen from the earth. It has to do with the perigee and that’s why it’s used.
It turns out that:
223 Synodic Months = 6585.322 days
242 Draconic Months = 6585.8 days
239 Anomalistic months = 6585.5 days
Thus the Saros cycle is 6585.322 days long, or 18 years 11 1/3 days, meaning that the next eclipse of that Saros occurs a third of the earth in longitude west of the previous eclipse. It takes three saros cycles for an eclipse to repeat near the same longitude. For instance, my first total solar eclipse was viewed from Quebec on July 20, 1963. The third Saros of that eclipse will occur on August 21, 2017. I expect to be around to see that, my 5th total solar eclipse. The path will shift southward and be seen across the continental United States.
There are something like 40 Saros cycles active at one time. Eclipses at the descending node head southward each eclipse, while those at the ascending node move northward.
The Eclipses of 2014
Here are the dates of the eclipses:
Total Lunar Eclipse April 15, 2014
Total Lunar Eclipse October 8, 2014
Partial Solar Eclipse October 23, 2014
Interestingly, all these eclipses will occur in the western part of the sky for us in northern Michigan. Both October eclipses will end with the eclipsed body setting before the official end of the eclipse. This means that both lunar eclipses are early morning eclipses and the solar eclipse will be a late afternoon eclipse.
Lunar eclipses start and end with the moon traveling through the earth’s penumbral shadow. It’s been my experience that this shadow only becomes visible in the half hour before and after the partial phases of the eclipse. The partial phase of the Tuesday April 15th lunar eclipse will start at 1:58 a.m., totality starts at 3:06 and ends at 4:24; with the partial phase ending at 5:33 as twilight begins to brighten.
The Wednesday October 8th lunar eclipse will start later in the morning. The partial phase will start at 5:14 a.m. Totality will run from 6:25 to 7:24 a.m. all in the growing morning twilight. Sunrise and moonset will interrupt the eclipse by 7:57.
The partial solar eclipse is on Thursday October 23. The eclipse will begin around 5:33 p.m. for Traverse City with sunset at 6:44. Times and whether the eclipse is visible at all depend on the location of the observer.
NASA diagrams, maps, and more information on these eclipses can be found here.
