02/22/2018 – Ephemeris – The blue-white star at Orion’s knee

February 22, 2018 Leave a comment

Ephemeris for Thursday, February 22nd. The Sun will rise at 7:32. It’ll be up for 10 hours and 49 minutes, setting at 6:21. The Moon, 1 day before first quarter, will set at 1:46 tomorrow morning.

The bright star at the bottom right corner of the big upright rectangle that is the giant hunter Orion’s body in the south-southeast is Rigel. It is a white star with a bluish tinge. It compares in brightness with Betelgeuse at the opposite end of Orion’s rectangle, though it’s usually a bit brighter. The mismatch in color makes brightness comparisons difficult. Rigel is about 860 light years away, It’s 23 times the mass of the Sun, 120 thousand the times brighter than the Sun, and a diameter almost the size of the orbit of Mercury. It’s age is thought to be about 8 million years. It has a visual companion star that can be seen in amateur telescopes. It’s not that dim, but suffers by being close to the arc light brightness of Rigel.

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

Addendum

Orion's named stars

Orion’s named stars including the belt stars. Created using Stellarium.

Rigel A & B

Rigel with its companion star as photographed through a telescope. No attribution. Source: http://washedoutastronomy.com/content/urban-orion?page=1

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Categories: Ephemeris Program, stars Tags: ,

02/21/2018 – Ephemeris – Let’s take our weekly look at the bright planets

February 21, 2018 Leave a comment

Ephemeris for Wednesday, February 21st. The Sun will rise at 7:33. It’ll be up for 10 hours and 46 minutes, setting at 6:19. The Moon, 2 days before first quarter, will set at 12:38 tomorrow morning.

Let’s take our weekly look at the bright planets. All of the bright naked eye planets save two are in the morning sky now. Mercury crossed behind the Sun 4 days ago and will become visible in the evening twilight in a couple of weeks. Also heading away from the Sun after sunset is Venus which sets 51 minutes after the Sun, and might be just visible low in the west-southwest from around 6:30 to about 6:50 p.m. At 7 in this morning’s twilight bright Jupiter is in the south-southwest to the left of it is dimmer Mars and below and right of it the red star Antares. The two are about the same brightness now. Saturn is low in the southeast. Jupiter will rise at 1:06 tomorrow morning, with Mars rising at 3:06. Saturn will end the procession, rising at 4:36 a.m.

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

Addendum

Venus after sunset.

Venus, low in the west-southwest at 6:30 p.m., February 21, 2018. Created using Stellarium.

Binocular Moon

The crescent Moon as it might be seen in binoculars at 8 p.m. tonight. February 21, 2018. Created using Stellarium.

Morning planets

The morning planets of Jupiter, Mars and Saturn. Seen at 7 a.m. as morning twilight brightens, February 21, 2018. Created using Stellarium.

Telescopic Jupiter and Saturn

Jupiter and Saturn with heir brighter satellites this morning at 7 a.m. February 21, 2018. They are displayed at the same scale. Saturn in about twice as far as Jupiter. Its disk is a bit smaller than Jupiter’s so it appears about half as large. The extent of the rings appear to be about the same as Jupiter’s diameter. Created using Stellarium.

Planets at sunset and sunrise of a single night

Planets at sunset and sunrise of a single night starting with sunset on the right on February 21, 2018. The night ends on the left with sunrise on February 22nd. Click on the image to enlarge. Created using my LookingUp program.

02/20/2018 – Ephemeris – Tonight’s the night to spot a chain of three of my favorite craters

February 20, 2018 Leave a comment

Ephemeris for Tuesday, February 20th. The Sun will rise at 7:35. It’ll be up for 10 hours and 43 minutes, setting at 6:18. The Moon, 3 days before first quarter, will set at 11:29 this evening.

I was a day off in my Moon calculations yesterday. The three of my favorite craters, just south of the partially illuminated Sea of Tranquility will be visible tonight. From north to south or top to bottom, near the terminator or sunrise line is Theophilus, which slightly overlaps the crater wall of Cyrillus, then a bit farther south another older crater Catharina. These craters were named by a Jesuit astronomer Giovanni Battista Riccioli (Ri’cholli). He even named a crater Copernicus, even though he followed the Church teachings of the time he didn’t believe in the Copernican Sun centered system, but the system put forth by Danish astronomer Tycho Brahe where the Moon and Sun circled the Earth, but the other planets circled the Sun.

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

Addendum

Crescent Moon

The crescent Moon on the evening of February 20th, 2018. showing the craters discussed in the test. Created using Virtual Moon Atlas and rotated to approximate its orientation in the sky after sunset.

Repeating from yesterday:  For anyone east of here who can see the Moon at 19:00 UT, on the 20th should see Theophilus shadow filled with the crater rim and the central peak poking into sunlight.  It should be visible from Europe and the Mid East.  Let me know with a comment if I guessed right.

02/19/2018 – Ephemeris – A trio of craters emerge into sunlight on the moon tomorrow night

February 19, 2018 Leave a comment

Whoops, I set my Virtual Moon Atlas app to the 20th instead of the 19th.  I’m fixing the transcript for the blog readers, but the original program will go out as is.  Tomorrow’s program will be substantially the same.

Ephemeris for President’s Day, Monday, February 19th. The Sun will rise at 7:36. It’ll be up for 10 hours and 40 minutes, setting at 6:16. The Moon, half way from new to first quarter, will set at 10:23 this evening.

The crescent Moon tomorrow will be revealing a trio of my favorite craters, just south of the partially illuminated Sea of Tranquility. From north to south or top to bottom, near the terminator or sunrise line is Theophilus, which slightly overlaps the crater wall of Cyrillus, than a bit farther south another older crater Catharina. These craters were named by a Jesuit astronomer Giovanni Battista Riccioli in his book New Almagest in 1651. Most of his crater names have stuck. He didn’t believe in the Copernican Sun centered system or the strict Earth centered system of Ptolemy, but the system put forth by Danish astronomer Tycho Brahe where the Moon and Sun circled the Earth, but the other planets circled the Sun.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Crescent Moon

The crescent Moon on the evening of February 20th, 2018. showing the craters discussed in the test. Created using Virtual Moon Atlas and rotated to approximate its orientation in the sky after sunset.

For anyone east of here who can see the Moon at 19:00 UT, on the 20th should see Theophilus shadow filled with the crater rim and the central peak poking into sunlight.

02/16/2018 – Ephemeris – The Crab Nebula

February 16, 2018 Comments off

Ephemeris for Friday, February 16th. The Sun will rise at 7:41. It’ll be up for 10 hours and 31 minutes, setting at 6:12. The Moon, 1 day past new, will set at 7:09 this evening.

The way the horns of Taurus the bull are shown in the sky, they are long and pointed above the head, not like a Texas Longhorn, off to the side. Near the tip of the eastern most horn is a faint and small fuzzy object. When Charles Messier saw it in 1758 he placed it as number 1 in his famous catalog of fuzzy objects that weren’t comets. It in 1913 it was realized that it was seen before. On July 5th, 1054 AD to be precise by Chinese astronomers. It, for a few weeks became the third brightest object in the sky after the Sun and Moon. It was a supernova, a massive star ending its life in a big explosion. In the 19th century Lord Rosse saw it with his huge telescope and called it the Crab Nebula. In its center is a tiny neutron star that spins 30 times a second.

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

Addendum

Crab Nebula (M 1) finder Chart

Crab Nebula (M 1) finder Chart. Orientation for 9 p.m. February 16th. It’s overall magnitude is 8.4 making it difficult to spot with binoculars or a telescope finder. I usually center the horn tip star Zeta Tauri and shift the telescope west a bit. Chart created using Cartes du Ciel (Sky Charts).

Crab Nebula

Hubble Space Telescope view of the Crab Nebula. Visually it appears a an oval blob. Credit NASA/ESA.

Crab Nebula Pulsar

The heart of the Crab Nebula and activity around the neutron star, which also is a pulsar as seen in x-rays by the Chandra satellite. Credit: NASA/CXC/A.Jubett.

02/15/2018 – Ephemeris – There are three solar eclipses this year, today is the first

February 15, 2018 Comments off

Ephemeris for Thursday, February 15th. The Sun will rise at 7:43. It’ll be up for 10 hours and 28 minutes, setting at 6:11. The Moon is new today, and won’t be visible. There will be a solar eclipse today that will be a partial blocking of the Sun for parts of Antarctica and southern South America. This is the first solar eclipse to occur since the Great American Eclipse last August. There are three solar eclipses this year and they are all partials with the core of the Moon’s shadow just missing the Earth to the north or south. This year there is another total lunar eclipse, but we will be facing the Sun in daytime when it happens and won’t be able to see it. That lunar eclipse will be visible in Europe and Asia July 27th. One of the other partial solar eclipses will occur 2 weeks before and the other two weeks after that lunar eclipse. That happens when the Moon passes very near the center of the Earth’s shadow.

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

Addendum

Circumstanced for eclipses.

There are two eclipse seasons a year at an average interval of 5.7 months. Usually there is a solar and a lunar eclipse at each season, unless there is a central lunar eclipse, when it can be bracketed by a partial solar eclipse about two weeks before and again after. Public domain with annotations by the author.

02/14/2018 – Ephemeris – Let’s take our weekly look at the bright planets

February 14, 2018 Comments off

Ephemeris for St. Valentine’s Day and Ash Wednesday, February 14th. The Sun will rise at 7:44. It’ll be up for 10 hours and 25 minutes, setting at 6:09. The Moon, 1 day before new, will rise at 7:42 tomorrow morning.

Let’s take our weekly look at the bright planets. All of the bright naked eye planets save one are in the morning sky now. Heading away from the Sun after sunset is Venus which sets 42 minutes after the Sun, and probably is not visible in the bright evening twilight. That will improve in a couple of weeks. At 7 in this morning’s twilight bright Jupiter is in the south to the left of it is dimmer Mars and below it the red star Antares. The two are about the same brightness now. The name Antares means “Rival of Mars”. Saturn is very low in the southeast. Jupiter will rise at 1:31 tomorrow morning, with Mars rising at 3:13. Saturn will end the procession, rising at 5:01 a.m.

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

Addendum

This morning

Morning planets

The morning planets of Jupiter, Mars and Saturn. Seen at 7 a.m. as morning twilight brightens, February 14, 2017. Created using Stellarium.

Telescopic Jupiter and Saturn

Jupiter and Saturn with their brighter satellites this morning at 7 a.m. February 14, 2018. They are displayed at the same scale. Saturn in about twice as far as Jupiter. Its disk is a bit smaller than Jupiter’s so it appears about half as large. The extent of the rings appear to be about the same as Jupiter’s diameter. Created using Stellarium.

This evening

Venus, the planet of love

Venus, the planet of love, about to set over Lake Michigan at 6:30 p.m., February 14, 2018. While a lovely planet in our skies, it is rather a hell hole inside it’s atmosphere. Created using Stellarium.

All night planets

Planets at sunset and sunrise of a single night

Planets at sunset and sunrise of a single night starting with sunset on the right on February 14, 2018. The night ends on the left with sunrise on February 15th. Mercury is not shown because it is mostly south of the Sun. It will be in superior conjunction on the 17th. Click on the image to enlarge. Created using my LookingUp program.