06/26/2020 – Ephemeris – The stars known as the Horse and Rider

June 26, 2020 Comments off

Jun 26. This is Bob Moler with Ephemeris for Friday, June 26th. Today the Sun will be up for 15 hours and 33 minutes, setting at 9:32, and it will rise tomorrow at 5:59. The Moon, 2 days before first quarter, will set at 1:28 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 very close to Mizar which is 6 times brighter.

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

Addendum

Mizar finder animation

Mizar finder animation for the Big Dipper’s orientation in late June at 11 pm where I live or an hour and a half after sunset. Created using Stellarium and GIMP.

Mizar and Alcor as they would appear in a telescope

Mizar and Alcor as they might appear in a telescope. Mizar is a binary star in a telescope. The other star in the field is apparently a background star. The brighter star of Mizar is Mizar A, while the dimmer is Mizar B. It turns out that Mizar A and B plus Alcor are all spectroscopic binaries, meaning the companion stars are too close to resolve in telescopes, but whose motion shows up in the spectra of the stars. Mizar and Alcor are around 80 light years away. Created using Stellarium.

06/25/2020 – Ephemeris – The bright star Spica

June 25, 2020 Comments off

This is Ephemeris for Thursday, June 25th. Today the Sun will be up for 15 hours and 33 minutes, setting at 9:32, and it will rise tomorrow at 5:58. The Moon, 3 days before first quarter, will set at 12:59 tomorrow morning.

Low in the southwest at 11 p.m. is the bright star Spica which can be found from all the way back overhead to the Big Dipper. Follow the arc of the handle of the Big Dipper to the bright star Arcturus high in the southwest. Then straighten the curve of the arc to a straight spike which points to Spica. Arcturus is much brighter than Spica and has an orange tint to Spica’s bluish hue. In fact Spica is the bluest of the 21 first magnitude stars. That means that it is hot. Actually Spica is really two blue stars orbiting each other in 4 days. Spica is 250 light years away, which is reasonably close. Spica was an important star to the ancient Greeks. One temple was built, and aligned to its setting point.

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

Addendum

Spica finder chart

Spica finder chart using my LookingUp program fo 11 p.m. tonight June 25.

06/24/2020 – Ephemeris – Let’s look at the naked-eye planets for this week

June 24, 2020 Comments off

This is Bob Moler with Ephemeris for Wednesday, June 24th. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:32, and it will rise tomorrow at 5:58. The Moon, 3 days past new, will set at 12:27 tomorrow morning.

Let’s look at the naked-eye planets for this week. Jupiter now rises in the evening, tonight it’s at 10:42 pm in the east-southeast. Saturn will rise 18 minutes later at 11pm right behind Jupiter. Mars, is stretching its lead left of Saturn and will rise at 1:36 am in the east. Its now down to 83.4 million miles (134.3 million km) away, as the Earth slowly overtakes it at the rate of about 4 million miles (6.4 million km) a week. Jupiter and Saturn will be hanging out between Sagittarius and Capricornus this year while Mars is slowing its rapid eastward motion now two constellations over in Pisces. Finally, Venus will rise at 4:26 am in the east-northeast low in the twilight as our Morning Star.

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

Addendum

The Moon as seen through binoculars or small telescope

The Moon as seen through binoculars or small telescope tonight June 24, 2020. Note earthshine on the night side of the Moon. Created using Stellarium.

Jupiter & Saturn at midnight

Jupiter & Saturn at midnight. Note the Teapot of Sagittarius to the right of Jupiter and the stars of Scorpius including Antares farther right. Click on the image to enlarge. Created using Stellarium.

Four of the five naked-eye planets stretched out on this panorama from northeast to southwest at 5 am tomorrow morning June 25, 2020. Click on the image to enlarge. Created using Stellarium.

Telescopic planets

The planets as seen in a telescope (north up) with the same magnification tomorrow morning June 25, 2020. Apparent diameters: Jupiter, 46.96″; Saturn, 18.28″, rings, 42.58″, Mars, 10.99″, and Venus 47.10″. Mars also shows an enlargement showing surface detail. The ” symbol means seconds of arc (1/3600th of a degree.) Click on the image to enlarge. Created using Cartes du Ciel (Sky Charts).

Planets and the Moon on a single night

Planets and the Moon at sunset and sunrise of a single night starting with sunset on the right on June 24, 2020. The night ends on the left with sunrise on the 25th. The closeness of Jupiter and Saturn in the morning sky unfortunately overlays planets and labels. Click on the image to enlarge. Created using my LookingUp program.

06/23/2020 – Ephemeris – Arcturus: a look at the Sun’s future

June 23, 2020 Comments off

This is Ephemeris for Tuesday, June 23rd. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:32, and it will rise tomorrow at 5:58. The Moon, 2 days past new, will set at 11:49 this evening.

Arcturus, a red giant star is about two thirds the way up the sky in the southwest at 11 p.m. It’s one of the earliest stars to appear in twilight, being nearly tied in brightness with Vega, a white star nearly as high in the east. A pointer to Arcturus is the handle of the Big Dipper, following the arc of the handle to Arcturus. Though only 37 light years away, it’s not from around here. It’s passing through the galactic disk from north to south. Arcturus is about 7 billion years old, and is about 8% more massive than our Sun. It appears to be starting its red giant phase, after running out of hydrogen to fuse to helium in its core and is beginning to fuse helium. It’s a preview of coming attractions for our Sun when it gets that old.

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

Addendum

Arcturus finder diagram

Arcturus is easy to find. It’s the brightest star in the southwest in the evening. This is 11 pm tonight June 23, 2020. Note the Big Dipper and its handle to the upper right. Created using Stellarium.

06/22/2020- Ephemeris – Summer has begun

June 22, 2020 Comments off

This is Ephemeris for Monday, June 22nd. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:32, and it will rise tomorrow at 5:57. The Moon, 1 day past new, will set at 11:04 this evening.

On Friday’s program I was way too busy with the summer solstice and the annular eclipse in Asia to properly give summer its due, so here goes. Last Saturday the northern end of the Earth’s axis was tilted toward the Sun to its maximum extent, giving the northern hemisphere its most direct sunlight, and the longest daylight hours. North of the arctic circle of 66 ½ degrees latitude got 24 hours of daylight, and the north pole midday in its six months of continuous sunlight. At the south pole it’s literally midnight of its six months night. The northern hemisphere got its greatest amount of heat from the Sun that day, however this part of the Earth is still warming up, so our hottest days average in late July when the shortening daylight hours and the lowering of the Sun in the south can’t maintain the heat anymore and we begin to cool.

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

Addendum

Earth's position at the solstices and equinoxes

Earth’s position at the solstices and equinoxes. This is an not to scale oblique look at the Earth’s orbit, which is nearly circular. The Earth is actually farthest from the Sun on July 4th. Click on the image to enlarge. Credit: ESO (European Southern Observatory which explains the captions in German and English.

Solstices

Comparing the sun’s path at the summer and winter solstices. This is a stereographic representation of the whole sky which distorts the sky and magnifies the size of the sun’s path near the horizon.

06/19/2020 – Ephemeris – Summer arrives tomorrow with an eclipse of the Sun the next day

June 19, 2020 Comments off

This is Ephemeris for Friday, June 19th. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:31, and it will rise tomorrow at 5:57. The Moon, 2 days before new, will rise at 5:25 tomorrow morning.

Tomorrow afternoon at 5:43 pm summer will begin, as the Sun reaches its greatest northerly excursion, right over the tropic of Cancer, 23 ½ degrees north latitude on the Earth’s surface. It’s called the summer solstice for those of us north of the equator. Early Sunday morning there will be an annular eclipse of the Sun. We won’t see it in the United States, however it will be visible for parts of Africa and southern Asia. The Moon will be too far away to completely cover the face of the Sun leaving a ring or annulus at maximum eclipse, a so-called Ring of Fire. It is the second of a triad of eclipses this eclipse season. Two weeks ago there was a slight eclipse of the Moon and two weeks from now another slight eclipse of the Moon to finish the season.

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

Addenda

Annular Eclipse

Eclipse Map for june 21, 2020

Areas of the Earth where the solar eclipse of June 21, 2020 will be visible. The central double red line delineates the path of annularity. Click on the image to see the original chart. Credit NASA GSFC, Fred Espenak.

Annular eclipse May 10 1994

My photograph of the Annular eclipse May 10 1994 taken east of Toledo, Ohio, May 10, 1994.

Summer Solstice

Earth and local area near summer solstice

Earth and magnified local area near summer solstice. Image taken near local noon June 17, 2020. Credit NOAA DSCOVR satellite orbiting the Sun-Earth L1 point 994,970 miles (1,601,432 kilometers) sunward from the Earth. For once it’s clear enough to see the mitten of the Lower Peninsula of Michigan.

The Sun's path on the summer solstice

The Sun’s path through the sky on the summer solstice day from Traverse City, MI. Created using my LookingUp program..

06/18/2020 – Ephemeris – Finding the constellation Hercules

June 18, 2020 Comments off

This is Ephemeris for Thursday, June 18th. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:31, and it will rise tomorrow at 5:56. The Moon, 3 days before new, will rise at 4:48 tomorrow morning.

Orion, the hard luck mythological Greek hunter gets a splashy constellation in the winter sky, but the greatest hero of all, Hercules, gets a dim group of stars on the border between the spring and summer stars. At 11 p.m. Hercules is very high in the east-southeast. It is located above and right of the bright star, Vega in the east. Hercules’ central feature is a box shaped of star wider at the top than the bottom, called the Keystone, which represents the old boy’s shorts. From each top corner extend lines of stars that are his legs, from the bottom stars, the rest of his torso and arms extend. So in one final indignity he’s upside down in our sky. Some see him crouched down, club upraised holding the Hydra about to throttle it. For those with a telescope it contains the beautiful globular star cluster M13.

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

Addendum

Hercules finder

Hercules animation showing neighboring stars at 11 p.m. for mid June, Click on image to enlarge. Created using Stellarium.

M13

M13, the Great Globular Star Cluster in Hercules. Credit: Scott Anttila

Stars and M13 visuble in Binoculars in the Keystone of Hercules

Stars and M13 (Great Star Cluster in Hercules) visible in binoculars in the Keystone of Hercules. Click in the image to enlarge. Created using Stellarium.

06/17/2020 – Ephemeris – Let’s look for the naked-eye planets for this week

June 17, 2020 Comments off

This is Bob Moler with Ephemeris for Wednesday, June 17th. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:31, and it will rise tomorrow at 5:56. The Moon, half way from last quarter to new, will rise at 4:18 tomorrow morning.

Let’s look for the naked-eye planets for this week. Jupiter now rises before midnight at 11:12 pm in the east-southeast. Saturn will rise 17 minutes later at 11:29 right behind Jupiter. Mars, is stretching its lead left of Saturn and will rise at 1:53 am in the east. Its now down to 83.4 million miles (134.3 million km) away, as the Earth slowly overtakes it at the rate of about 4.3 million miles (7.0 million km) a week. Jupiter and Saturn will be hanging out between Sagittarius and Capricornus this year while Mars is slowing its rapid eastward motion now two constellations over in Pisces. Finally, Venus will rise at 4:51 am in the east-northeast low in the twilight as our new Morning Star.

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

Addendum

Evening planets, which rose in the 11 pm hour

Jupiter and Saturn finder animation for midnight June 18, 2020. For other locations, approximately 2 1/2 hours after sunset. Also showing the stars of the Teapot of Sagittarius to the upper right of the SE compass point and most, except the bottom stars of Scorpius in the south. Click on the image to enlarge. Created using Stellarium and GIMP.

Panorama of the morning planets

Panorama of the morning planets at 5:15 am or about 45 minutes before sunrise tomorrow June 18, 2020. Click on the image to enlarge. Created using Stellarium.

Binocular Moon

The Moon as it might be seen in binoculars tomorrow morning before sunrise June 18, 2020. Created using Stellarium.

Telescopic planets

The planets as seen in a telescope (north up) with the same magnification. Jupiter and Saturn tomorrow morning of June 18, 2020. Apparent diameters: Jupiter, 46.34″; Saturn, 18.14″, rings, 42.36″ and Mars, 41.38″. Mars also shows an enlargement showing surface detail. The ” symbol means seconds of arc (1/3600th of a degree.) Click on the image to enlarge. Created using Cartes du Ciel (Sky Charts).

Planets and the Moon on a single night

Planets and the Moon at sunset and sunrise of a single night starting with sunset on the right on June 17, 2020. The night ends on the left with sunrise on the 18th. The closeness of Jupiter and Saturn in the morning sky unfortunately overlays planets and labels. Click on the image to enlarge. Created using my LookingUp program.

06/16/2020 – Ephemeris – One circlet of stars, two constellations: old world and new world

June 16, 2020 Comments off

This is Ephemeris for Tuesday, June 16th. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:30, and it will rise tomorrow at 5:56. The Moon, 3 days past last quarter, will rise at 3:52 tomorrow morning.

High in the south-southeast at 11 this evening can be seen a small nearly circular constellation of Corona Borealis, the Northern Crown. It is just below Boötes, the kite shaped constellation off the handle of the Big Dipper. According to Greek myth the crown was given by the gods to the princess Ariadne, daughter of King Minos of Crete. The crown is more like a tiara with the bright star Alphecca at the front. To the Anishinaabe people, who are natives of our region it is the Sweat Lodge. Part of what we call Hercules next to it is the Exhausted Bather, who is lying on the ground after the ceremony. The seven stones that are heated for the Sweat Lodge are the Pleiades, now too close to the Sun to be seen.

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

Addendum

Corona Borealis and Sweat Lodge

Animated Corona Borealis/Sweat Lodge Finder Chart looking to the south-southeast at 11 p.m. June 16th. Click on the image to enlarge Created using Stellarium and GIMP.

06/15/2020 – Ephemeris – Now is the date of the earliest sunrise and it isn’t even summer yet

June 15, 2020 Comments off

This is Ephemeris for Monday, June 15th. Today the Sun will be up for 15 hours and 33 minutes, setting at 9:30, and it will rise tomorrow at 5:56. The Moon, 2 days past last quarter, will rise at 3:30 tomorrow morning.

Today, give or take a day is the date of the earliest sunrise. The latest sunrise was about January 2nd, leaving only about 165 days for the transition of three hours, 24 minutes and since we still have five days to the longest day. The sunset change rate is a lot more leisurely. It has to do with the tilt of Earth’s axis and its slightly elliptical orbit. It’s why sundials don’t keep proper time. Though most sundials appear to be decorative and are not set up correctly anyway. Besides sundials can’t cope with time zones, and daylight time unless they are specially built for a particular location. Anyway the latest sunset will be on the 26th, 200 days since the earliest sunset, on December 9th, last year.  The sunset retreat to December 9th will take 165 days, and the sunrise advance will take 200 days until next January 2nd next year.

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