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06/27/2017 – Ephemeris – Arcturus as a look at the Sun’s future

June 27, 2017 1 comment

Ephemeris for Tuesday, June 27th. Today the Sun will be up for 15 hours and 32 minutes, setting at 9:31, and it will rise tomorrow at 5:59. The Moon, 3 days before first quarter, will set at 12:18 tomorrow morning.

With the Moon brightening the night sky, let’s take a look at the star Arcturus, which with its pointer, the curve of the Big Dipper’s handle is slipping into the high western sky. Arcturus is the 4th brightest night time star, though some think the star Vega, high in the east is brighter. They are different colors because Arcturus is orange, while Vega is whiter than the Sun. Arcturus is a preview of what the Sun will become in four or five billion years from now. It is only 10% more massive than the Sun and is that much older than the Sun, so it is turning into its red giant stage, after running out of hydrogen to turn into helium in its core to produce energy. The helium is now compressing and heating to begin its reaction.

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

Addendum

Arcturus finder chart

Arcturus finder chart with the Big Dipper and Vega as guide posts. Created using Stellarium.

Here’s one of my prior posts about Arcturus, about its great space velocity:  https://bobmoler.wordpress.com/2016/04/26/04262016-ephemeris-arcturus-just-passing-through/

06/26/2017 – Ephemeris – Latest sunset and the apparent positions of the Summer Triangle stars

June 26, 2017 1 comment

Ephemeris for Monday, June 26th. Today the Sun will be up for 15 hours and 32 minutes, setting at 9:31, and it will rise tomorrow at 5:59. The Moon, 3 days past new, will set at 11:40 this evening.

Tonight we have the latest sunset of the year. From now on until December sunsets will become earlier. Other than the sunrise and sunset numbers, we’ll begin to notice it for real in a few weeks. At first that realization strikes me a sad note that summer is beginning to end. However the astronomer in me realizes that means more night-time hours, and that the summer Milky Way is coming. Of the three bright stars of the Summer Triangle overhead and in the east, two of its stars are in the milky band. They are Deneb to the north and Altair to the south. Vega, closest to the zenith is not in the band. Actually all the stars we see with the naked eye or small telescopes belong to the Milky Way galaxy.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

The constellations Lyra, Cygnus and Aquila

Looking at the stars of the Summer Triangle and their location in and near the Milky Way band. Created using Stellarium.

06/23/2017 – Ephemeris – Astronomy events this weekend

June 23, 2017 1 comment

Ephemeris for Friday, June 23rd. Today the Sun will be up for 15 hours and 33 minutes, setting at 9:31, and it will rise tomorrow at 5:58. The Moon is new today, and won’t be visible.

Tomorrow afternoon and evening will be what we call a Sun & Star Party at the Sleeping Bear Dunes National Lakeshore. This event will be at the Dune Climb. From 4 to 6 p.m., the Sun will be featured using two types of telescopes, one showing the sun’s photosphere in what we call white light, and another showing the chromosphere above it in the light of hydrogen giving a completely different view. Starting at 9 p.m. will be a star party, actually really a planet party, viewing the planets Jupiter and Saturn, plus other objects visible in the deepening twilight.

Sunday at 11 a.m. to 4 p.m. members of the society will be in the parking lot of the NMC Laboratory on Aero Park Drive in Traverse City to view the Sun as part of the Michigan Clean Energy Conference and Fair.

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

Addendum

Viewing the transit

Kids viewing the Sun through the society’s Lunt hydrogen alpha solar telescope.

06/22/2017 – Ephemeris – Now that it’s summer, lets check out the Summer Triangle

June 22, 2017 1 comment

Ephemeris for Thursday, June 22nd. Today the Sun will be up for 15 hours and 33 minutes, setting at 9:31, and it will rise tomorrow at 5:57. The Moon, 1 day before new, will rise at 5:45 tomorrow morning.

We’re a day into summer, and the asterism or informal constellation called the Summer Triangle can be seen rising in the east as it gets dark. Highest of the three bright stars is Vega in the constellation Lyra the harp, whose body is seen in a narrow parallelogram nearby. The second star of the triangle is Deneb lower and left of Vega, It appears dimmer than Vega because it is by far the most distant of the three. The third star of the Summer Triangle is seen farther below and a right of Vega. It is Altair in Aquila the eagle, and the closest. Altair is 16.5 light years away, Vega is 27 light years while Deneb may be a whopping 2600 light years away. One light year is 6 trillion miles (9 trillion km).

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

Addendum

The Summer Triangle July 5, 2012 at 11 p.m. Created using Stellaruim and The Gimp.

The Summer Triangle. Created using Stellarium and The Gimp.

06/21/2017 – Ephemeris – Checking out the bright planets on the first day of summer

June 21, 2017 1 comment

Ephemeris for Wednesday, June 21st. Today the Sun will be up for 15 hours and 33 minutes, setting at 9:31, and it will rise tomorrow at 5:57. The Moon, 2 days before new, will rise at 4:54 tomorrow morning.

Let’s take our weekly look at the bright planets on this first day of summer. Dominating the evening sky now is Jupiter in the southwest. The bright blue-white star Spica, which pales in comparison to it, is seen left and below it. In even the smallest telescopes Jupiter’s four largest moons can be seen. They shift positions night from to night and sometimes even as you watch. Jupiter will set at 2:18 a.m. Saturn can now be seen in the evening as twilight fades in the southeast. It is now officially an evening planet after opposition last week. At 5 a.m. both Saturn and Venus will be seen in the morning twilight. Brilliant Venus will be low in the east tomorrow morning after rising at 3:37 a.m.

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

Addendum

Evening Planets

Jupiter and Saturn and the southern evening constellations at 10:30 p.m., June 21, 2017. Click on the image to enlarge. Created using Stellarium.

Jupiter and moons

Jupiter and its four Galilean moons as they might be seen in a telescope at 10:30 p.m,. June 21, 2017. Created using Cartes du Ciel (Sky Charts).

Saturn and moons

Saturn and its brightest moons overnight June 21/22, 2017. Created using Cartes du Ciel (Sky Charts).

Morning planets

Saturn, Venus and the rising crescent Moon at 5 a.m. June 22, 2017. Click on the image to enlarge. Created using Stellarium. Click on the image to expand.

Telescopic Venus

Venus as it might be seen through a telescope at 5 a.m. June 22, 2017. This is displayed at a larger scale/magnification than the Jupiter or Saturn images above. Created using Stellarium.

Moon

The skinny crescent moon as it might be seen in binoculars, after 5 a.m., June 22, 2017. Created using Stellarium.

Planets and Moon on a single night

Planets at sunset and sunrise of a single night starting with sunset on the right on June 21, 2017. The night ends on the left with sunrise on June 22. Click on the image to enlarge. Created using my LookingUp program.

06/20/2017 – Ephemeris – Summer will begin overnight tonight

June 20, 2017 1 comment

Ephemeris for Tuesday, June 20th. Today the Sun will be up for 15 hours and 33 minutes, setting at 9:31, and it will rise tomorrow at 5:57. The Moon, half way from last quarter to new, will rise at 4:11 tomorrow morning.

Summer will begin overnight at 12:25 a.m. (4:25 UT June 21, 2017) The sun will at its highest at noon today and tomorrow, well at local solar noon that is, which is 1:44 p.m. in the Interlochen Traverse City area. At that time the Sun will reach an altitude or angle above the southern horizon of nearly 69 degrees. If you want to get an idea of the difference between that and the Sun at the winter solstice, check out Saturn tonight. It is almost to the point in the sky where the Sun was at the winter solstice. Notice how low it is in the sky, and how few hours it is up. The cause is the tilt of the earth’s axis of 23 and a half degrees. It gives us a 47 degree span of altitudes of the sun over the year. It is not the sun’s distance that causes seasons, as we’ll see next month.

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

Addendum

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.

Earth at summer solstice

Earth from the DSCOVR satellite at the June solstice 2015. Credit NOAA

06/19/2017 – Ephemeris – The hero Hercules in the stars

June 19, 2017 1 comment

Ephemeris for Monday, June 19th. Today the Sun will be up for 15 hours and 33 minutes, setting at 9:30, and it will rise tomorrow at 5:57. The Moon, 2 days past last quarter, will rise at 3:33 tomorrow morning.

The greatest Greek 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 high in the eastern sky. It is located above and right of the bright star, Vega, also in the east. Hercules’ central feature is a keystone shaped box of stars, 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. Just below and right of the topmost star of the keystone is what looks like a fuzzy star in binoculars or small telescope. It is the Great Hercules Globular Star Cluster, also known as M13, home to a million stars.

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

Addendum

Hercules

Hercules animation showing neighboring stars, constellation outlines, deep sky objects, and constellation art for Hercules. Created using Stellarium. Click on image to enlarge.

M13

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

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