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02/08/2018 – Ephemeris – The wonderfully named stars of Orion

February 8, 2018 Comments off

Ephemeris for Thursday, February 8th. The Sun will rise at 7:53. It’ll be up for 10 hours and 8 minutes, setting at 6:01. The Moon, 1 day past last quarter, will rise at 3:09 tomorrow morning.

The constellation of Orion the hunter is visible in the south at 9 p.m. The stars of Orion are interesting in themselves. Starting at the top left of the seven bright stars of Orion’s torso is Betelgeuse the bright red star, whose name means something like “Armpit of the Giant”. The star in Orion’s other shoulder is Bellatrix the “Amazon Star”. Below are the three stars of Orion’s belt, from left to right; Alnitak, Alnilam and Mintaka. Their names mean “Girdle”, “Belt of Pearls”, and “Belt” respectively. Down to Orion’s knees we look on the left to the star Saiph pronounced ‘safe’ which means “Sword”, though it is some ways from the stars of Orion’s sword. Finally there’s the bright blue-white star Rigel whose name means “Left Leg of the Giant”.

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

Addendum

Orion with star names.

The named stars of Orion. Created using Stellarium.

Betelgeuse, pronounced Beetlejuice is the name of a 1988 movie, where Betelgeuse (spelled properly) is a particularly mischievous demon.  Don’t say his name three times, or he’ll come and ‘help’ you.  Oops, I did.  It is a red giant star near the end of its life.

Bellatrix, is now known to most of us now as the first name as the first name of Bellatrix Lestrange from J. K. Rowling’s Harry Potter book and movie series.  Other members of the Black family have astronomical names, such as Regulus (Leo) Black, and Sirius (Canis Major) Black.

The names of the belt stars were taught to me by Evelyn Grebel of the Grand Rapids Public Museum in the late 1950s.  She was one of the founders of the Grand Rapids Amateur Astronomical Association.  The names Alnitak, Alnilam and Mintaka have stuck with me ever since.  It was through her that I was able to worm my way into working at the museum’s new then unnamed planetarium.  I also remember being in her office with her, listening to the radio as Alan Shepard made his historic suborbital flight on May 5th, 1961.

Rigel is a hot blue-white star, and will probably become a red giant star like Betelgeuse.  There is another bright star named Rigel, but most don’t know it.  It’s Rigel Kentaurus, the leg of the centaur of Centaurus.  It’s better known as Alpha Centauri, a catalog designation, and the nearest star to the solar system.

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02/05/2018 – Ephemeris – The rabbit that got away

February 5, 2018 1 comment

Ephemeris for Monday, February 5th. The Sun will rise at 7:57. It’ll be up for 10 hours even, setting at 5:57. The Moon, 2 days before last quarter, will rise at 12:06 tomorrow morning.

Orion, the central winter constellation is seen in the south at 9 p.m. He is a hunter, but he’s preoccupied with the charge of Taurus the bull from the upper right. At Orion’s feet, and unnoticed by him is the small constellation of Lepus the hare. It’s very hard to see a rabbit in its dim stars: however, I do see a rabbit’s head ears and shoulders. A misshapen box is the head and face of this critter facing to the left. His ears extend upwards from the upper right star of the box, and the bend forward a bit. Two stars to the right of the box and a bit farther apart hint at the front part of the body. Some see a whole rabbit facing the other way. In Lepus telescopes can find M79, a distant globular star cluster, one of the few in the winter sky.

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

Addendum

Lepus animation

Pick your favorite Lepus outline. Cartes du Ciel, Stellarium, or Hallo Northern SKY (with grid lines).

01/22/2018 – Ephemeris – The Pup

January 22, 2018 1 comment

Ephemeris for Monday, January 22nd. The Sun will rise at 8:11. It’ll be up for 9 hours and 25 minutes, setting at 5:37. The Moon, 2 days before first quarter, will set at 11:24 this evening.

Sirius is the brightest night-time star and is located in the southeast at 9 p.m. below and a bit left of Orion the Hunter. We’ve visited Sirius last week. There is another star in the Sirius system that is practically invisible due to its dazzling glare. It’s Sirius B, nicknamed the Pup, alluding to Sirius’ Dog Star title. The tiny star was suspected as far back as 1834 due to Sirius’ wavy path against the more distant stars. Sirius is only 8.6 light years away. Sirius A and the Pup have 50 year orbits of each other. The star was first seen by Alvan Clark in 1862 while testing a new telescope. The Pup was the first of a new class of stars called white dwarfs. The Pup is about the size of the Earth, with the mass of our Sun, and 5 times hotter than the Sun’s surface. It’s out of fuel and slowly collapsing.

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

Addendum

Orion and Canis Major

Orion and Canis Major Animation for 9 p.m. January 20, 2017. Created using Stellarium and GIMP.

Sirius' path

Sirius A & B’s path in the sky showing the wobble that betrayed the Pup’s presence. Credit Mike Guidry, University of Tennessee.

Sirius A and B

Sirius A and B (near the diffraction spike to the lower left), A Hubble Space Telescope photograph. Credit NASA, ESA.

01/19/2018 – Ephemeris – Orion’s large hunting dog

January 19, 2018 1 comment

Ephemeris for Friday, January 19th. The Sun will rise at 8:14. It’ll be up for 9 hours and 19 minutes, setting at 5:33. The Moon, 3 days past new, will set at 8:15 this evening.

The brightest star-like object in the evening sky is Sirius, also known as the Dog Star. It also is the brightest night-time star in our skies period. Tonight at 9 p.m. it’s located low in the southeastern sky. The Dog Star name comes from its position at the heart of the constellation Canis Major, the great dog of Orion the hunter, which is seen almost like he’s begging, feet to the right. The three stars of Orion’s belt tilt to the southeast and point to Sirius. The name Sirius means ‘Scorcher’, a reference to its great brilliance and twinkling. To me it has a blue tinge like an arc light in a telescope. Its Egyptian name was Sothis, and its appearance in the dawn skies in late June signaled the flooding of the Nile, and the beginning of the Egyptian agricultural year.

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

Addendum

Orion and Canis Major

Orion and Canis Major Animation for 9 p.m. tonight. Created using Stellarium and GIMP.

01/18/2018 – Ephemeris – The spectacular Great Orion Nebula

January 18, 2018 1 comment

This is Bob Moler with Ephemeris for Thursday, January 18th. The Sun will rise at 8:14. It’ll be up for 9 hours and 17 minutes, setting at 5:32. The Moon, 2 days past new, will set at 7:15 this evening.

The constellation Orion the hunter is the south-southeast at 9 p.m. its upright rectangle of four stars frame his belt of three stars in a straight line and still tilt a bit to the left. Below the belt is what appear to the unaided eye as three more stars arranged vertically, his sword. Binoculars aimed at the middle stars of the sword will find a glowing haze around those stars. That is the Great Orion Nebula. It is the birth place of stars, and is even illuminated by a clutch of four hot young stars. One of the discoveries of the Hubble space telescope are what appear, and are tiny cocoons of gas and dust in which stars condense and form. They are called Proplyds, which are short for protoplanetary disks. In each one is the red center, a young star just beginning to shine.

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

Addendum

The lower part of Orion with the Great Orion Nebula. Created using Stellarium.

The lower part of Orion with the Great Orion Nebula. Created using Stellarium.

The Great Orion Nebula (M42) long exposure photograph

The Great Orion Nebula (M42) long exposure photograph by Scott Anttila. Includes all the sword stars.

A new video just posted by NASA

01/16/2018 – Ephemeris – More thoughts about Orion and the Wintermaker

January 16, 2018 1 comment

Ephemeris for Tuesday, January 16th. The Sun will rise at 8:15. It’ll be up for 9 hours and 13 minutes, setting at 5:29. The Moon is new today, and won’t be visible.

We come back to the central constellation of the winter sky Orion the hunter, now in the southeast at 9 p.m. with his three stars of his belt in a straight line, with his upper shoulder stars above and knees below. In one Greek story he was killed by the sting of a scorpion so the gods made sure the rising of the constellation Scorpius would chase him out of the sky to the west. To the Greeks he was a hapless hero. Orion is mentioned in the Bible in the book of Job. The name for Orion in Hebrew is Kesil, meaning “Fool”. To the native peoples around the Great Lakes, the stars here are those of the Wintermaker, who stretches his arms from Aldebaran in Taurus to Procyon in Canis Minor. When he is in the evening sky it is indeed winter.

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

Addendum

As the scorpion approaches Orion makes a hasty exit

When the scorpion (Scorpius) crawls over the southeastern horizon, Orion takes a powder to the west. This is about 5 a.m. in mid January. Created using Stellarium.

Orion-Wintermaker finder animation

Orion-Wintermaker finder animation for 9 p.m., January 16. Created using Stellarium and GIMP.

12/18/2017 – Ephemeris – The little dog shall lead

December 18, 2017 1 comment

Ephemeris for Monday, December 18th. The Sun will rise at 8:14. It’ll be up for 8 hours and 49 minutes, setting at 5:03. The Moon is new today, and won’t be visible.

The constellation Orion has two hunting dogs. At 9 p.m. we’ll see one of them, the lesser dog, Canis Minor whose bright star Procyon is low in the East. Just two stars mark the constellation. Is it a dachshund or maybe a hot dog? The name Procyon means “Before the dog”, an odd title. It means that though east of Sirius, the bright dog star in Orion’s large dog, Canis Major, it rises before Sirius, due to its more northerly position in the sky. At 9 Sirius is just rising in the east-southeast. In many ways Procyon is nearly a twin of Sirius. It shines with the same white color, although a bit cooler, and has a white dwarf companion like Sirius. It’s a bit farther away than Sirius’ 8.6 light years. Procyon is at a distance of 11.46 light years.

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

Addendum

Procyon rising before Sirius

Stars and constellations in the east at 9 p.m., about 4 hours after sunset, on December 18th. This only works for locations above 30 degrees north latitude. Created using Stellarium.