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Posts Tagged ‘Big Dipper’

5/15/2018 – Ephemeris – Two thirds thru spring

May 15, 2018 Comments off

Ephemeris for Tuesday, May 15th. Today the Sun will be up for 14 hours and 49 minutes, setting at 9:04, and it will rise tomorrow at 6:13. The Moon is new today, and won’t be visible.

Here we are at the middle of May, nearly two-thirds through spring and in the west only a few winter stars remain. Castor and Pollux of Gemini are horizontal in the west, Procyon the Little Dog Star is below and left of them, Capella in Auriga is in the northwest, but for most of the IPR listening area it will never quite set. At 10:30 Betelgeuse in Orion the hunter will be setting, chased from the skies by Scorpius the scorpion, which is rising in the southeast. In one story it is the sting of this scorpion that killed him. Already at that time two-thirds of the stars of the summer Triangle are up. Bright Vega in Lyra the harp, and Deneb in Cygnus the swan. The Big Dipper reigns overhead as spring is in full bloom.

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

Addendum

Goodbye winter, hello summer

The sky dome for 10:30 p.m. May 15, 2018 showing the stars and constellations. It may not work for any latitude or time, but it works for our location, near 45 degrees north. Created using Stellarium.

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05/14/2018 – Ephemeris – Big Dipper: Pointer to the Stars

May 14, 2018 Comments off

Ephemeris for Monday, May 14th. Today the Sun will be up for 14 hours and 47 minutes, setting at 9:03, and it will rise tomorrow at 6:14. The Moon, 1 day before new, will rise at 6:45 tomorrow morning.

The Big Dipper points to other stars and constellations. Right now the Big Dipper is nearly overhead. The front bowl stars point to Polaris, the North Star which never seems to move in the sky. The handle can be used to find two stars. First follow the arc of the handle away from the bowl to find the fourth brightest night-time star Arcturus in the base of the kite shaped constellation of Boötes. Straighten the arc to a spike and continue to the south and you will come to the bright blue-white star Spica in Virgo the virgin. You can remember these stars with the phrase “Follow the arc of the handle to Arcturus and then spike to Spica” or if you prefer the alternate pronunciation of the latter star “Speak to Speeka”.

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

Addendum

As can be seen below, there was one pointer function that didn’t make it into the program:  A leaky dipper drips on Leo.

Big Dipper Pointer to the Stars

Using the Big Dipper as a pointer to other stars. The pointers to Polaris could be life saving, since it is always north. The view is southward. The cross displayed near the center is the zenith. One might want to lay down to take all this in. Created using my LookingUp program.

04/23/2018 – Ephemeris – The Ursa Major Association

April 23, 2018 Comments off

Ephemeris for Monday, April 23rd. The Sun rises at 6:45. It’ll be up for 13 hours and 52 minutes, setting at 8:37. The Moon, 1 day past first quarter, will set at 4:15 tomorrow morning.

The usual impression is to think that the stars of a constellation are actually located close together. This is usually not true. The stars of a constellation can be at vastly different distances. The Big Dipper is different. The five stars, excepting the two end stars of the dipper and 12 other dimmer stars in the general area are of similar distance and have the same motion through space. The group is called the Ursa Major Moving Cluster or Ursa Major Association, and is moving about 9 miles per second relative to the solar system to the east and south. An association is a rather loose, sparse star cluster. This association lies about 75 light years away. If it were five times farther away, it would be the same distance as the Pleiades.

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

Addendum

The Big Dipper

Craig Brown’s drawing of where the stars of the Big Dipper are and are heading. Click on the image to go to Craig’s WordPress post.

04/19/2018 – Ephemeris – The Big Dipper’s stars Mizar and Alcor

April 19, 2018 Comments off

Ephemeris for Thursday, April 19th. The Sun rises at 6:51. It’ll be up for 13 hours and 41 minutes, setting at 8:32. The Moon, 3 days before first quarter, will set at 12:47 tomorrow morning.

The most interesting star in the Big Dipper is Mizar and its dim companion Alcor. It is the second star from the end of the handle, where the bend in the handle takes place. Folks with good vision can see the dimmer star right next to Mizar. In ancient times it was used as an eye test for visual acuity for warriors as such it was known as the “Horse and the Rider”.

Mizar is second magnitude, in the second rank of star brightness invented by the Greek astronomer Hipparchus in the 2nd century BC. He ranked stars in 6 classes, from first magnitude for the brightest to 6th for the dimmest visible to the naked eye. Alcor comes in at 4th magnitude. It does suffer a bit by being close to Mizar which is 6 times brighter.

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

Addendum

The Big Dipper with Mizar & Alcor

The Big Dipper, almost overhead at 10 p.m. April 19 with Mizar and Alcor pointed out. Created using Stellarium.

Telescopic Mizar and Alcor

A view of Mizar and Alcor as seen in a telescope. Mizar is itself a binary star. In actuality both components of Mizar and Alcor are spectroscopic binaries, which are too close to split, but their presence is detected by their Doppler motions with spectrographs. Created using Stellarium.

04/09/2018 – Ephemeris – Follow the arc to Arcturus

April 9, 2018 Comments off

Ephemeris for Monday, April 9th. The Sun will rise at 7:09. It’ll be up for 13 hours and 11 minutes, setting at 8:20. The Moon, 1 day past last quarter, will rise at 4:40 tomorrow morning.

The fourth brightest night-time star is now up in the east. 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 remembering the line “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 times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Arc to Arcturus

Look high in the east on a spring evening to follow the arc of the Big Dipper’s handle to Arcturus. Created using Stellarium ans GIMP.

Categories: stars Tags: ,

02/13/2018 – Ephemeris – The Big Dipper as a pointer to other stars and constellations

March 13, 2018 Comments off

Ephemeris for Tuesday, March 13th. The Sun will rise at 7:58. It’ll be up for 11 hours and 47 minutes, setting at 7:46. The Moon, 4 days before new, will rise at 6:42 tomorrow morning.

With the Big Dipper up in the northeastern sky it is a sign that spring is coming. At 9 p.m. The Big Dipper can be used to find other stars and constellations. The Big Dipper’s most famous function is in locating Polaris the North Star. It’s a good way of finding directions at night. The altitude of Polaris, that is angle above the horizon, will give one’s approximate latitude north of the equator. Another constellation that can be found is Leo the lion. It is rising in the east in the evening, but it can also be found from the Big Dipper by imagining that a hole were drilled in the bottom of the bowl to let the water leak out. It would fall on Leo’s back. The Big Dipper can be used to find two more stars, but they have not yet risen.

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

Addendum

The Big Dipper

The Big Dipper points to Polaris, the, North Star, and to Leo the lion at 9 p.m., March 13th. In another hour the 4th brightest night-time star Arcturus will appear above the eastern horizon pointed to by the arc of the handle of the Big Dipper. We’ll revisit the Big Dipper next month when Arcturus and Spica will also be found by the use of the Big Dipper. Created using Stellarium and Libre Office.

03/12/2018 – Ephemeris – The Fisher is rising as spring approaches

March 12, 2018 Comments off

Ephemeris for Monday, March 12th. The Sun will rise at 8:00. It’ll be up for 11 hours and 44 minutes, setting at 7:45. The Moon, 4 days past last quarter, will rise at 6:05 tomorrow morning.

Now in the evening the Big Dipper has moved up in the northeast. The Anishinaabek peoples around the Great Lakes, like the Ottawa and Chippewa saw instead of a dipper or a bear: Ojiig the Fisher. It’s a magical weasel-like creature who, with some animal friends, brought summer to the Earth. The story is too long to relay here, but my telling of it is here. For his trouble he was slain, and was placed among the stars of the sky by the Great Spirit Manitou where we see him today. His blood is said to paint the trees with the fall colors. However as the Fisher rises in the northeast in late winter and early spring it is a signal for the maple trees to bring forth their sweet sap.

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

Addendum

The Fisher rising

Finding the Big Dipper and the Fisher at 9 p.m., March 12, 2018. Click on the image to enlarge. Created using Stellarium and GIMP.

The Anishinaabek constellation drawings are from Ojibwe Sky Star Map Constellation Guide  by Annette S. Lee, William Wilson, Jeffrey Tibbets and Carl Gawboy available locally and online.  They are part of the latest editions of Stellarium, a free planetarium program.  Links to it are on the left.  Other information and links are available within the Sky Lore tab.

Here’s one of the links: http://www.nativeskywatchers.com/.  It also contains links to Lakota star maps and lore.