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11/16/2020 – Ephemeris – How to find the Pleiades or Seven Sisters

November 16, 2020 Comments off

This is Ephemeris for Monday, November 16th. Today the Sun will be up for 9 hours and 31 minutes, setting at 5:13, and it will rise tomorrow at 7:43. The Moon, 1 day past new, will set at 6:31 this evening.

A marvelous member of the autumn skies can be found low in the east after 8 in the evening. It is the famous star cluster called the Pleiades or the Seven Sisters. I might also add the ‘Tiny Dipper’. Many people can spot a tiny dipper shape in its six or seven stars, and mistake it for the Little Dipper. When I was nearsighted*, though corrected, I never had been able to see more than a few stars and a bit of fuzz. However, with binoculars, even I could see over a hundred stars appear along with the dipper shape of the brightest. The fuzz I saw was unresolved stars, but in photographs the Pleiades actually contain wisps of the gas and dust they are currently passing through. In Greek mythology the sisters were daughters of the god Atlas. I’ll be revisiting the Pleiades several times this autumn, winter, and as they disappear in the west in evening twilight next spring.

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

*My vision was corrected with cataract surgery a few years ago. The Pleiades now have a granular appearance now.

Addendum

Pleiades finder animation

Pleiades finder animation looking east at 8 pm, November 16th. Click on the image to enlarge. Created using Stellarium.

Aldebaran

Aldebaran in the ‘V’ shape of the Hyades (The face of Taurus the bull) with the Pleiades above. Created using Stellarium.

Greek Pleiades

The Greek Pleiades a painting by Elihu Vedder in the Metropolitan Museum of Art, New York City. Public Domain.

08/21/2020 – Ephemeris – Great moments in astronomy: The Great Debate in 1920

August 21, 2020 Comments off

This is Bob Moler with Ephemeris for Friday, August 21st. Today the Sun will be up for 13 hours and 44 minutes, setting at 8:37, and it will rise tomorrow at 6:54. The Moon, 3 days past new, will set at 10:26 this evening.

One hundred years ago there were two lectures given to the National Academy of Science by Drs. Harlow Shapley and Heber Curtis. This became know as the Great Debate. Shapley believed that the Milky Way was the entire universe, and evidenced by the distribution of globular star clusters in the sky that the Sun was near the periphery of it, and that spiral nebulae were part of the Milky Way. Curtis on the other hand thought that the Sun was near the center of the Milky Way, however that the spiral nebulae were other island universes, or milky ways of their own. Over the next decade each was proved right in part and wrong in part. We are not near the center of the Milky Way, but those spiral nebulae were indeed other milky ways or galaxies.

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

Addendum

M51 drawing

A drawing of the Whirlpool Galaxy, M51 (NGC 5194 & 5195) by Lord Rosse with his 72 inch telescope in the mid 19th century. This is the only “spiral nebula” I have actually seen as a spiral visually in a telescope, though not as well as he saw it. Public Domain.

M51 photo

With the advent of photography many spiral nebulae were discovered. The Whirlpool Galaxy, M51. Credit Scott Anttila.

Press Release for the Great Debate

This is a copy of the Press release issued for the two presentations of Harlow Shapley and Heber Curtis at the annual meeting of the National Academy of Sciences April 26, 1920 that have come to be known as the “Great Debate”. Credit NAS.

For more on the Great Debate follow this link.

Astronomy has advanced a long way in the last 100 years.  And what’s crazy is that I actually met Dr. Harlow Shapley at the opening of the Planetarium of the Grand Rapids Public Museum around 1960. I was in my first year at Grand Rapids Junior College at the time. I had been a member of the of the local astronomy club for several years by then. Two friends and I became planetarium rats and have wormed our way into volunteering to working with it before a formal structure was set up to operate it.

 

05/21/2020 – Ephemeris – A star cluster in a most unusual spot

May 21, 2020 Comments off

This is Ephemeris for Thursday, May 21st. Today the Sun will be up for 15 hours and 3 minutes, setting at 9:11, and it will rise tomorrow at 6:07. The Moon, 1 day before new, will rise at 6:16 tomorrow morning.

High in the south at 10:30 p.m. or so is a tiny and faint constellation of Coma Berenices, or Berenice’s hair. In it are lots of faint stars arrayed to look like several strands of hair. The whole group will fit in the field of a pair of binoculars, which will also show many more stars. The hank of hair supposed belonged to Berenice II, Queen of Egypt, in the 3rd century BCE. Coma Berenices is the second closest star cluster to us at only 250 light years away, after the Hyades, the face of Taurus the bull a winter constellation. It’s in an odd spot for a galactic star cluster, which are supposed to lie in the plane of the Milky Way. It’s actually seen at the galactic pole, as far as possible away from the milky band. It’s a matter of perspective because it’s so close to us. It’s still really in the plane of the Milky Way.

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

Addendum

Coma Berenices and the galactic pole

Coma Berenices and galactic coordinated showing how close to the galactic pole it is. The bright star Arcturus at the left edge.  Leo’s hind end is at the lower right. Created using Cartes du Ciel (Sky Charts).

Coma Berenices

Approximate 7 power binocular field of view of the Coma Berenices Star Cluster. Created using Cartes du Ciel (Sky Charts).

Note: There is another cluster in the constellation.  It’s called the Coma Cluster.  It’s a cluster of over a thousand galaxies a bit over 300 million light years away.

12/17/2019 – Ephemeris – Hyades, the face of Taurus the Bull

December 17, 2019 Comments off

Ephemeris for Tuesday, December 17th. Today the Sun will be up for 8 hours and 48 minutes, setting at 5:03, and it will rise tomorrow at 8:15. The Moon, 2 days before last quarter, will rise at 11:14 this evening.

The face of the constellation Taurus the bull looks like the letter V sideways above the rising Orion the Hunter in the east at 9 p.m. The bright star at the tip of a letter V of stars is Aldebaran. Look with binoculars at the letter V shape and you will see the stars of the Hyades star cluster The Hyades is the closest star cluster to us, at about 153 light years. And is important for that reason. Before satellites like Hipparcos and Gaia. The Hyades was the only star cluster to be directly measured by a technique called parallax, using the radius of the Earth’s orbit as one side of a surveyors enormous triangle. Its many stars at the same distance were used to determine distances of star clusters even farther away. Additional techniques based on the distance of the Hyades allowed us to measure distances to the galaxies.

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

Addendum

Aldebaran

Aldebaran in the ‘V’ shape of the Hyades (The face of Taurus the bull) with the Pleiades above. Created using Stellarium.

10/29/2019 – Ephemeris – Finding the Pleiades or Seven Sisters

October 29, 2019 Comments off

Ephemeris for Tuesday, October 29th. Today the Sun will be up for 10 hours and 19 minutes, setting at 6:36, and it will rise tomorrow at 8:17. The Moon, 2 days past new, will set at 7:57 this evening.

A marvelous member of the autumn skies can be found low in the east northeast after 9 in the evening. It is the famous star cluster called the Pleiades or the Seven Sisters. I might also add the ‘Tiny Dipper’. Many people can spot a tiny dipper shape in its six or seven stars, and mistake it for the Little Dipper. When I was nearsighted, though corrected, I never had been able to see more than a few stars and a bit of fuzz. However with binoculars, even I can see over a hundred stars appear along with the dipper shape of the brightest. The fuzz I saw was unresolved stars, but in photographs the Pleiades actually contain wisps of the gas they are passing through currently. In Greek mythology the sisters were daughters of the god Atlas.

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

Addendum

Pleiades finder animation

Finding the Pleiades animation for 9 p.m. October 29, 2019. The Pleiades is surrounded by constellations I’ve described earlier this year and one yet to be described, Taurus the bull of which the cluster is a part.  The V of stars near the horizon is Taurus’ head and is another star cluster, the Hyades, the half sisters to the Pleiades. Created using Stellarium and GIMP.

The Pleiades, about what you'd see in binoculars.

The Pleiades, about what you’d see in binoculars, though not as brilliant.  One of my old photographs.  With my 11 inch f/4.5 Dobsonian using a 40mm eyepiece that gives a field of view that encompasses the Pleiades, all I can say is Wow!

Greek Pleiades

The Greek Pleiades a painting by Elihu Vedder in the Metropolitan Museum of Art, New York City. Public Domain.

11/27/2018 – Ephemeris – The beautiful Pleiades or Seven Sisters

November 27, 2018 Comments off

Ephemeris for Tuesday, November 27th. The Sun will rise at 7:55. It’ll be up for 9 hours and 10 minutes, setting at 5:05. The Moon, 2 days before last quarter, will rise at 9:52 this evening.

While I’ve mentioned the Pleiades with regard to its neighboring constellations several times this autumn I haven’t looked at this beautiful star cluster itself. The Pleiades appears as a group of six or seven stars visible to the naked eye, out of over a hundred stars, and is also known as the Seven Sisters. Some also mistake it for the Little Dipper, due to the little bowl shape in the center of the cluster. I call it the “tiny dipper”. The real Little Dipper is now hanging off Polaris in the north. There are a lot of stories about the Pleiades from many different cultures. From the Greek and Roman cultures we get our best known stories of them, that the seven sisters were the daughters of the god Atlas and Pleione. The 9 brightest stars bear the names of the sisters and their parents.

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

Addendum

Named Pleiads
The named stars of the Pleiades. This is also showing more stars than can be seen with the naked eye. This is the number of stars that can be seen in binoculars, which is the best way to observe them. Most telescopes are too offer too much magnification to fit all the stars in. A thirty power wide angle eyepiece can just fit all the stars in. Created using Stellarium.
The eastern sky at 9 p.m.
How to find the Pleiades in the eastern sky tonight.  Created using Cartes du Ciel (Sky Charts).

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.

03/26/2018 – Ephemeris – The Moon will slide below the Beehive star cluster tonight

March 26, 2018 Comments off

Ephemeris for Monday, March 26th. The Sun will rise at 7:34. It’ll be up for 12 hours and 28 minutes, setting at 8:02. The Moon, 2 days past first quarter, will set at 5:34 tomorrow morning.

Tonight the gibbous Moon will be seen among the stars of Cancer the crab. It will just about completely drown Cancer’s dim stars out. That is no exception to one of the famous group of stars in Cancer, the Beehive star cluster. It is going to take binoculars or a small telescope to spot them. The star cluster will be at the 11 o’clock position from the Moon. When looking for the cluster try to keep the Moon out of your field of view. The cluster is about 4 moon-widths away, so aim high and slowly aim those binoculars down. There will be other times in the next few months to catch the Moon near the Beehive, when the Moon will be a not so overwhelming crescent as the cluster moves westward in the evening sky with the rest of the stars.

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

Addendum

The Moon and the Beehive Star Cluster

The Moon and the Beehive Star Cluster tonight at 9 p.m. March 26, 2018. The star cluster will be very difficult to spot. Created using Stellarium, however I had to boost the brightness of the stars and eliminate the atmosphere control to darken the sky enough to see the cluster. Good luck!

Cancer the Crab

Cancer the crab finder chart for a dark night. Note the beehive cluster, also known to amateur astronomers as M44, along with other catalog names. Prior to the invention of the telescope this cluster was known as Praesepe which means “Manger”. Created using Stellarium and GIMP.

01/08/2018 – Ephemeris – The Pleiades in Greek myth

January 8, 2018 Comments off

Ephemeris for Monday, January 8th. The Sun will rise at 8:19. It’ll be up for 9 hours and 1 minute, setting at 5:20. The Moon, at last quarter today, will rise at 1:17 tomorrow morning.

The large and bright constellation of Orion is now in the southeast at 9 p.m. It is seen as an upright rectangle of bright stars, with a belt of three stars in the center. Orion is a minor character in Greek mythology. Orion was the son of Neptune, and was a hunter. He had an ill-fated romance with Merope, whose father King Oenopion, had him blinded. After having his sight restored, Orion became a companion of Diana goddess of the hunt and they wanted to marry. Apollo, Diana’s brother disapproved of Orion also and was able to trick Diana into accidentally killing Orion with an arrow. The heart-broken Diana then placed Orion in the sky with his hunting dogs, were we see him to this day.

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

Addendum

Hyades and Pleiades

The Pleiades (right) and the Hyades (left) in this photograph I took January 4, 2016.

Named Pleiads

The named stars of the Pleiades. This is also showing more stars than can be seen with the naked eye. This is the number of stars that can be seen in binoculars, which is the best way to observe them. Most telescopes are offer too much magnification to fit all the stars in. A thirty power wide-angle eyepiece can just fit all the stars in. Created using Stellarium.

11/06/2017 – Ephemeris – Taurus’ angry red eye, Aldebaran

November 6, 2017 1 comment

Ephemeris for Monday, November 6th. The Sun will rise at 7:27. It’ll be up for 9 hours and 57 minutes, setting at 5:24. The Moon, 3 days past full, will rise at 7:52 this evening.

Last night the Moon passed in front of or occulted the bright star Aldebaran. Above right of Moon tonight is Aldebaran the bright orange star with a V shape of other stars in the face of Taurus the bull. Aldebaran appears at the lower left tip of that letter V laying on it’s side. With the bright Moon, it might take binoculars to pull out the faint stars of the V. Aldebaran isn’t actually part of the group, called the Hyades star cluster. The cluster is about 153 light years away, while Aldebaran is 65 light years away. The star has an orange hue because its surface is cooler than the Sun’s. However Aldebaran is 44 times larger in diameter, and shines 425 times brighter than the Sun. The name Aldebaran means “Follower” because it follows the Pleiades star cluster above it.

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

Addendum

Aldebaran

Aldebaran in the Hyades (unlabeled), with also the Pleiades, unlabeled, at the top and the Moon. at 9 p.m., November 6, 2017. Created using Stellarium.