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Posts Tagged ‘Sirius’

02/20/2020 – Ephemeris – The Winter Triangle

February 20, 2020 Comments off

Ephemeris for Thursday, February 20th. Today the Sun will be up for 10 hours and 41 minutes, setting at 6:17, and it will rise tomorrow at 7:34. The Moon, 3 days before new, will rise at 6:53 tomorrow morning.

I usually talk about the Winter Circle of bright stars, but some other astronomers talk about the Winter Triangle. The stars involved are Betelgeuse in the hunter Orion, Sirius in Canis Major, Orion’s large hunting dog, and Procyon in Canis Minor, his other small hunting dog. These three stars enclose a rather blank piece of sky with the faint Milky Way running through it and the equally invisible constellation of Monoceros the unicorn. The Summer Triangle has three bright stars with no other close competition. The Winter Triangle has 4 other bright stars near it. Any three of these would make a nice triangle. One of these stars, Betelgeuse has been the news recently because it is dimming to an unprecedented degree.

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

Addendum

Winter Triangle

The Winter Triangle. It enclose a pretty blank space where Monoceros the unicorn lies. Created using Stellarium with my annotations for the Winter Triangle. By the way, Betelgeuse is currently only as bright as Bellatrix, the star next to the “n” in Orion.

02/17/2020 – Ephemeris – A look at Orion and his hunting dogs

February 17, 2020 Comments off

Ephemeris for President’s Day, Monday, February 17th. Today the Sun will be up for 10 hours and 32 minutes, setting at 6:13, and it will rise tomorrow at 7:39. The Moon, 2 days past last quarter, will rise at 4:27 tomorrow morning.

The great winter constellation or star group Orion the Hunter, is located in the southern sky at 9 p.m. His elongated rectangle of a torso is vertical. In the center of the rectangle are three stars in a line that make his belt. As a hunter, especially one of old, he has two hunting dogs. The larger, Canis Major can be found by following the three belt stars of Orion down and to the left. There lies the brilliant star called Sirius, also known as the Dog Star. It’s in the heart of a stick figure dog lower in the south facing Orion that appears to be begging. Canis Minor is just two stars found by extending Orion’s shoulder stars eastward where we find bright Procyon, the little dog star in the southeast.

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

Addendum

Orion and his hunting dogs

Orion and his hunting dogs with pointers as seen at 9 p.m. in mid February. Created using Stellarium.

12/19/2019 – Ephemeris – What does the bright star Procyon’s name mean?

December 19, 2019 Comments off

Ephemeris for Thursday, December 19th. Today the Sun will be up for 8 hours and 48 minutes, setting at 5:04, and it will rise tomorrow at 8:16. The Moon, at last quarter today, will rise at 1:42 tomorrow morning.

Visible low in the east at 8:30 p.m. will appear the star Procyon, sometimes called the little Dog Star. It’s in the constellation of Canis Minor, the little dog. It will rise at 8:05 p.m. for the Traverse City Interlochen area. Yet to rise at that time is the Dog Star itself, Sirius, the brightest night-time star. It won’t rise until 8:40 p.m., 35 minutes later even though Sirius is west of Procyon. I bring this up because the name Procyon means Before the Dog. At our latitude Procyon rises before any part of Canis Major, the big dog, Canis Major, that Sirius is in the heart of. This is sensitive to one’s latitude. At the equator, say in Ecuador. Sirius would rise first due to its westerly position by 54 minutes. You see Procyon is also north of Sirius and that makes all the difference.

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 19th. This only works for locations above 30 degrees north latitude. Created using Stellarium.

Procyon and Sirius will for observers located at 30º 30′ north latitude.  South of that latitude Sirius will rise first.

02/08/2019 – Ephemeris – Sirius has a companion

February 8, 2019 Comments off

Ephemeris for Friday, February 8th. Today the Sun will be up for 10 hours and 7 minutes, setting at 6:01, and it will rise tomorrow at 7:52. The Moon, half way from new to first quarter, will set at 9:48 this evening.

Sirius is the brightest night-time star and is located in the south-southeast at 9 p.m. below and a bit left of Orion the Hunter. We’ve visited Sirius yesterday. But there is another star in the Sirius system that is practically invisible due to Sirius’ dazzling glare. Its name is 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 and the Pup have 50 year orbits of each other. The Pup was first seen in 1862. The Pup was the first of a new class of stars to be discovered, white dwarfs. The Pup is a dying star with the mass of the Sun, collapsed down to the size of the Earth.

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

Addendum

Orion's Belt points to Sirius

Orion’s Belt points to Sirius. Created using Stellarium.

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.

Categories: Ephemeris Program, stars Tags: , ,

02/07/2019 – Ephemeris – Siriusly, folks.

February 7, 2019 Comments off

Ephemeris for Friday, February 8th. Today the Sun will be up for 10 hours and 7 minutes, setting at 6:01, and it will rise tomorrow at 7:52. The Moon, half way from new to first quarter, will set at 9:48 this evening.

At 9 in the evening the great constellation of Orion the hunter can be seen in the south. Its large rectangle of bright stars is now upright, while in the center is a row of three stars, his belt. These stars tilt downward to the left to a very bright star merrily twinkling in the south-southeast. This star is called Sirius, also known as the Dog Star because it’s in the heart of Orion’s larger hunting dog, Canis Major. It is an arc light white star as seen in binoculars or telescope. It’s a neighboring star, just twice the distance of the closest star to the sun at 8.6 light years. It’s name, Sirius, has nothing to do with a dog, but is from the Greek meaning scorching for its brightness or sparkling, due to its intense twinkling.

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

Addendum

Orion's Belt points to Sirius

Orion’s Belt points to Sirius. Created using Stellarium.

01/28/2019 – Ephemeris – The celestial unicorn

January 28, 2019 Comments off

Ephemeris for Monday, January 28th. Today the Sun will be up for 9 hours and 39 minutes, setting at 5:45, and it will rise tomorrow at 8:05. The Moon, 1 day past last quarter, will rise at 2:52 tomorrow morning.

Within a triangle bounded by stars Betelgeuse in Orion, Sirius in Canis Major and Procyon in Canis Minor, called the Winter Triangle appears a nearly starless patch of sky to the naked eye. In here is the constellation Monoceros, the unicorn. Unfortunately for observers without optical aid Monoceros, though large, is devoid of any but the faintest stars. Maybe that’s why no one sees unicorns anymore. It has many faint stars because the Milky Way runs through it. To the telescope it is a feast of faint nebulae or clouds of gas and dust, the birth place of stars, including the red rose of the Rosette Nebula, and the strange and tiny Hubble’s Variable Nebula. It also contains beautiful telescopic triple star system, Beta (β) Monocerotis.

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

Addendum

Monoceros

Monoceros finder chart animation. Created using Stellarium and GIMP.

Rosette Nebula

Rosette Nebula in the infrared from the Spitzer Space Telescope. Credit: NASA/JPL/Caltech

Hubble's Variable Nebula

Hubble’s Variable Nebula photographed appropriately enough by the Hubble Space Telescope. Credit: NASA/ESA and The Hubble Heritage Team (AURA/STScI).

Monoceros DSO finder chart

Looking at some faint objects in Monoceros. NGC 2239 is the star cluster in the center of the Rosette Nebula. The nebula itself is extremely faint. It shows in photographs, but I’ve never seen it visually. The green circle shows Beta Monocerotis, the triple star. All these stars are extremely blue-white hot. Created using Cartes du Ciel (Sky Charts).

Beta Monocerotis

Telescopic Beta Monocerotis. William Hershel, discoverer of Uranus, said that it was “One of the most beautiful sights in the heavens.” Credit: F. Ringwald, Fresno State.

 

01/25/2019 – Ephemeris – Let’s find Orion’s hunting dogs

January 25, 2019 Comments off

Ephemeris for Friday, January 25th. Today the Sun will be up for 9 hours and 32 minutes, setting at 5:41, and it will rise tomorrow at 8:08. The Moon, 2 days before last quarter, will rise at 11:27 this evening.

The great winter constellation or star group Orion the Hunter, is located in the south-southeastern sky at 9 p.m. His elongated rectangle of a torso is tilting toward the vertical. In the center of the rectangle are three stars in a line that make his belt. As a hunter, especially one of old, he has two hunting dogs. The larger, Canis Major can be found by following the three belt stars of Orion down and to the left. There lies the brilliant star called Sirius, also known as the Dog Star. It’s in the heart of a stick figure dog low in the southeast facing Orion that appears to be begging. Canis Minor is just two stars found by extending Orion’s shoulder stars eastward where we find bright Procyon, the little dog star.

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

Addendum

Orion and his hunting dogs

Orion and his hunting dogs with pointers as seen at 9 p.m. in late January . Created using Stellarium.

02/12/2018 – Ephemeris – The Winter Circle

February 12, 2018 Comments off

Ephemeris for Monday, February 12th. The Sun will rise at 7:47. It’ll be up for 10 hours and 19 minutes, setting at 6:07. The Moon, 3 days before new, will rise at 6:29 tomorrow morning.

The winter skies are blessed with more first magnitude stars than any other season. Six of these stars lie in a large circle centered on the seventh, It’s called the Winter Circle. This circle is up at 9 p.m. Starting high overhead is yellow Capella in Auriga the charioteer. Moving down clockwise is orange Aldebaran in the face of Taurus the Bull. Then down to Orion’s knee we find blue-white Rigel. Down and left is the brightest star of all the brilliant white Sirius the Dog Star in Canis Major, lowest of these stars in the south-southeast. Moving up and left is white Procyon in Canis Minor, Above Procyon is Pollux in Gemini the twins. All these are centered, well not quite, on Betelgeuse the bright red star in Orion’s shoulder.

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

Addendum

Winter Circle

The bright stars of winter arrayed in a circle (well almost). Created using Stellarium.

01/22/2018 – Ephemeris – The Pup

January 22, 2018 Comments off

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 Comments off

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.