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Posts Tagged ‘Callisto’

04/10/2018 – Ephemeris – How Boötes and the Great Bear got into the sky

April 10, 2018 Comments off

Ephemeris for Tuesday, April 10th. The Sun will rise at 7:07. It’ll be up for 13 hours and 14 minutes, setting at 8:21. The Moon, 2 days past last quarter, will rise at 5:14 tomorrow morning.

Appearing mid way up the sky in the east at 10 p.m. is the kite shaped constellation of Boötes the herdsman. The bright star Arcturus is at the bottom-right of the kite, pointed to by the arc of the handle of the Big Dipper, above it. In one Greek myth Boötes represents a young hunter named Arcas, son of Callisto, a beautiful young lady who had the misfortune of being loved by Zeus the chief of the Greek gods. Zeus’ wife Hera, found out about the affair, and since she couldn’t punish Zeus, turned the poor woman into an ugly bear. Arcas, unaware of the events surrounding his mother’s disappearance in his youth was about to kill the bear when Zeus intervened and placed them both in the sky to save her. To this day Boötes continues to chase the great bear Ursa Major around the pole of the sky each night.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Arcas and Callisto woodcut

Arcas about to slay the bear by the 17th century artist Baur. Source: University of Virginia Electronic Text Center

Arcas and Callisto

Bootes and Ursa Major aka Arcas chasing Callisto around the pole of the sky. Created using Stellarium.

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04/25/2016 – Ephemeris – Arcas and Callisto

April 25, 2016 Comments off

Ephemeris for Monday, April 25th.  The Sun rises at 6:41.  It’ll be up for 13 hours and 59 minutes, setting at 8:40.   The Moon, 3 days past full, will rise at 11:56 this evening.

Appearing mid way up the sky in the east at 10 p.m. is the kite shaped constellation of Boötes the herdsman.  The bright star Arcturus is at the bottom of the kite, pointed to by the arc of the handle of the Big Dipper, above it.  In one story Boötes represents a young hunter named Arcas, son of Callisto, a beautiful young lady who had the misfortune of being loved by Zeus the chief of the Greek gods.  Zeus’ wife Hera, found out about the affair, and since she couldn’t punish Zeus, turned the poor woman into an ugly bear.  Arcas, unaware of the events surrounding his mother’s disappearance was about to kill the bear when Zeus intervened and placed them both in the sky to save her.  To this day Boötes continues to chase the great bear Ursa Major around the sky each night.

Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Arcas and Callisto

Bootes and Ursa Major aka Arcas chasing Callisto around the pole of the sky. Created using Stellarium.

Arcas and Callisto woodcut

Arcas about to slay the bear by the 17th century artist Baur. Source: University of Virginia Electronic Text Center

04/12/2016 – Ephemeris – Can you tell the Jovian moons apart without a program?

April 12, 2016 Comments off

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

Jupiter's moons

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 moons tonight

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.

02/19/2015 – Ephemeris – Jupiter is beginning to take its rightful place as king of the evening sky

February 19, 2016 Comments off

Ephemeris for Friday, February 19th.  The Sun will rise at 7:37.  It’ll be up for 10 hours and 38 minutes, setting at 6:16.   The Moon, 3 days before full, will set at 6:10 tomorrow morning.

Jupiter is becoming noticeable in the evening sky in the east after 8 p.m.  The heavy atmosphere near the horizon make telescopic observations difficult because the planet and its satellites will appear fuzzy and have color fringes top and bottom.  Wait an hour or two for the planet to rise higher into quieter and thinner air to get the best telescopic views.  Jupiter is accompanied by four moons in telescopes.  Tonight they’re on one side of Jupiter, with Io closest, then Europa and Ganymede close to each other, while Callisto as usual appears to be the farthest satellite.  The face of Jupiter itself is crossed by dark belts and light zones that run in the same direction as the satellites orbit.  The moons change position from night to night.

Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Jupiter, the Moon and stars tonight

Jupiter, the Moon and stars tonight at 10 p.m., February 19, 2016. Created using Stellarium.

This image is shown smaller than actual size.  Image expansion lately hasn’t worked.  If you are using Firefox, right-click on the image, and then click on View Image.

Jupiter Tonight

Jupiter and its moons tonight, 10 p.m. February 19, 2016. Created using Stellarium.

Jupiter and moons

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 its Great Red Spot

Jupiter with its Great Red Spot November 18, 2012 by Scott Anttila.

The above image by Scott Anttila is actually much better that the image seen in small telescopes.  Advances in digital photography and processing allow the stacking and averaging of many images to create better pictures by  amateur astronomers with modest equipment than the best telescopes of a quarter century ago.

04/14/2015 – Ephemeris – Arcas and Callisto

April 14, 2015 Comments off

Ephemeris for Tuesday, April 14th.  The Sun will rise at 7:00.  It’ll be up for 13 hours and 25 minutes, setting at 8:26.   The Moon, 3 days past last quarter, will rise at 5:08 tomorrow morning.

Rising in the eastern sky at 10 p.m. tonight is the kite shaped constellation of Boötes the herdsman.  The bright star Arcturus is at the bottom of the kite, pointed to by the arc of the handle of the Big Dipper, overhead.  In one story Boötes represents a young hunter named Arcas, son of Callisto, a beautiful young lady who had the misfortune of being loved by Zeus the chief Greek god.  Zeus’ wife Hera, found out about it, and since she couldn’t punish Zeus, turned Callisto into an ugly bear.  Arcas, unaware of why his mother disappeared in his youth was about to kill the bear when Zeus intervened and placed them both in the sky.  Now Arcas as Boötes chases the Great Bear forever around the pole of the sky each night.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.

Addendum

Arcas and Callisto

Bootes and Ursa Major aka Arcas chasing Callisto around the pole of the sky. Created using Stellarium.

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12/03/2014 – Ephemeris – Bright planets: One early and one late

December 3, 2014 Comments off

Ephemeris for Wednesday, December 3rd.  The sun will rise at 8:01.  It’ll be up for 9 hours and 1 minute, setting at 5:03.   The moon, 3 days before full, will set at 5:48 tomorrow morning.

In reviewing which planets are visible tonight, it looks like we’re still down to two.  Venus, Saturn and Mercury are hanging around near the direction of the Sun.  It will be a little while before we see them again.  However we can see Mars, which will be low in the southwest at 7 p.m.  It will set at 8:29 p.m.  Mars’ setting time will slowly advance only 6 minutes between now and the end of the year.   Jupiter will rise at 10:28 p.m. in the east-northeast.  The best telescopic views will have to wait a couple of hours after that.  So if you’re more of an early bird rather than a night owl it might be better to view Jupiter with a telescope in the morning.  Jupiter has those four bright moons that change position daily, and sometimes while you watch.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.

Addendum

Mars

Mars in the southwest at 7 p.m. December 3, 2014. Created using Stellarium.

Moon

A binocular view of what the moon will look like at 7 p.m. December 3, 2014. Created using Stellarium.

Jupiter and the winter constellations

Jupiter rising with the winter constellations at 11 p.m., December 3, 2014. We’re actually looking at the eastern half of the sky. Created using Stellarium.

Jupiter at 6 a.m.

At 6 a.m. December 4, 2014 Jupiter and the winter constellations will swing into the southwest while out of the view the spring and early summer stars take over the eastern sky. Created using Stellarium.

Telescopic Jupiter

Telescopic view of Jupiter at 6 a.m. December 4, 2014. The moons on the left in order from left to right are Callisto, Ganymede and Europa. In the next hour the moons will appear to get even closer together, especially Ganymede and Callisto. Created using Stellarium.

01/09/2014 – Ephemeris – More on Jupiter’s Galilean moons.

January 9, 2014 Comments off

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 moons

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 eclipse

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.