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Archive for August, 2020

08/31/2020 – Ephemeris – Artemis, NASAs new program to land men and women on the Moon

August 31, 2020 Comments off

This is Ephemeris for Monday, August 31st. Today the Sun will be up for 13 hours and 15 minutes, setting at 8:20, and it will rise tomorrow at 7:05. The Moon, 2 days before full, will set at 6:10 tomorrow morning.

The Artemis program is the United States follow on, after more than 50 years, to return to the Moon. It’s main rocket, the Space Launch System or SLS uses components of the Space Shuttle that include the main engines, using 4 instead of three, and two longer solid boosters. The Orion capsule sits atop the second stage. Unlike Apollo, the lunar lander will be sent up on a separate rocket into lunar orbit. Eventually there will be a lunar orbiting space station called the Lunar Gateway as a way point. But not for the first attempt. NASA has accepted three bids for commercial landers, Dynetics with a squat lander with drop-tanks. The National team of several companies with an Apollo-like lander on steroids, and SpaceX’s Starship.

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

Addendum

Block 1 Space Launch System with Orion Capsule

Block 1 Space Launch System with Orion Capsule. Credit NASA.

Three Lunar Lander proposals

Three Lunar Lander proposals. Credit Dynetics, SpaceX, and Blue Origin.

08/28/2020 – Ephemeris – Tonight Jupiter and the Moon will appear together in the sky

August 28, 2020 Comments off

This is Ephemeris for Friday, August 28th. Today the Sun will be up for 13 hours and 24 minutes, setting at 8:25, and it will rise tomorrow at 7:02. The Moon, 3 days past first quarter, will set at 2:56 tomorrow morning.

Tonight at 9:33 pm the Moon will pass Jupiter in our skies. Jupiter will appear about 5 moon-widths above the Moon. It’s a good time to get out those binoculars or a small telescope to look at them. Jupiter will have its four brightest moons, two on each side. They are pretty close in. Tomorrow night they will all be on the west side of the planet. The waxing Gibbous Moon shows most of the Earth facing side now. The sunrise line a day ago brought the crater Copernicus into light on the east or left side of the Moon. Otherwise the east side of the Moon is flatter than the west side being dominated by two flat lunar seas, actually lava plains called the Sea of Clouds and Ocean of Storms. The Moon has never seen clouds or storms.

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

Addendum

Jupiter, Saturn and the Moon

Jupiter, Saturn and the Moon as they would appear to the naked eye at 9:33 pm tonight August, 28, 2020. Created using Stellarium which unfortunately shows the Moon dimmer than the planets. In reality is that the Moon very much brighter, almost overpowering the planets.

Telesscopic Jupiter

Jupiter and its 4 Galilean moons as the would appear in a telescope tonight August 28, 2020. Created using Cartes du Ciel (Sky Chart).

Gibbous Moon

The gibbous Moon tonight as it might appear in a low power telescope. Created using Stellarium.

 

08/27/2020 – Ephemeris – Unsolved mysteries: Dark Matter

August 27, 2020 Comments off

This is Ephemeris for Thursday, August 27th. Today the Sun will be up for 13 hours and 27 minutes, setting at 8:27, and it will rise tomorrow at 7:01. The Moon, 2 days past first quarter, will set at 1:58 tomorrow morning.

It was in the 1930s that some astronomer concluded by measuring the velocities of individual galaxies that galaxy clusters contain more mass that can be explained by the size and brightness of the galaxies within. Fritz Zwicky coined the term dark matter for it after his study in 1933. Vera Rubin and others discovered the effect of dark matter on the rotation rates of galaxies in the 1960s and 70s. Nobody knows what dark matter is. There are two leading theories that they are made of particles coined WIMPs and objects called MACHOs that don’t interact with normal matter except gravitationally. Astronomers do have fun with their acronyms. Dark matter is detected by their gravity and how it distorts the light from the galaxies behind it.

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

Addendum

Bullet Cluster showing what happened to the dark matter

This is called the Bullet Cluster. It’s two galaxy clusters that collided. The pink is hot gas visible in x-rays. The blue is added to show where dark matter resides. It is detected by studying the far distant galaxies beyond for distortion caused by the gravitational lensing of the dark matter. Most of the mass of the galaxy clusters is dark matter, which also contain hot gas and, of course the galaxies. When galaxy clusters collide the gas of the two clusters interact and are stripped out and the dark matter and galaxies go merrily on. Image Credit: NASA, ESA, CXC, M. Bradac (University of California, Santa Barbara), and S. Allen (Stanford University)

FYI: WIMPs = Weakly Interacting Massive Particles, MACHOs = MAssive Compact Halo Objects.

08/26/2020 – Ephemeris – Let’s look at a the naked-eye planets for this week

August 26, 2020 Comments off

This is Ephemeris for Wednesday, August 26th. Today the Sun will be up for 13 hours and 30 minutes, setting at 8:29, and it will rise tomorrow at 6:59. The Moon, 1 day past first quarter, will set at 1:09 tomorrow morning.

Let’s look at a the naked-eye planets for this week. Jupiter and Saturn are both low in the south-southeastern sky at 10 pm. Jupiter is the very bright one. To the left of it will be Saturn. They now seem to be separating a bit due to the Earth’s motion now, but they will cross paths in December. Both planets will be up most of the night with Jupiter setting first at 3:02 tomorrow morning and Saturn following at 3:45 am. The next planet visible will be Mars which will

rise at 10:36 pm. Its now down to 48.3 million miles (77.8 million kilometers) away, as the Earth slowly overtakes it at the rate of about 3.0 million miles (4.8 million kilometers) a week. Brilliant Venus will rise at 3:14 am and is moving ahead of the Earth in its orbit.

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

Addendum

Jupiter, Saturn and the Moon in the evening

Jupiter, Saturn and the Moon at 10 pm August 26, 2020. Note that the Moon is enlarged 3 times to show its phase. Click on the image to enlarge. Created using Stellarium.

Binocular Moon

The gibbous Moon as it might be seen tonight at 10 pm August 26, 2020. Created using Stellarium.

Venus and Mars in the morning

Venus and Mars at 6 am tomorrow morning August 27, 2020. Click on the image to enlarge. Created using Stellarium.

The planets as seen in a telescope (north up) with the same magnification Apparent diameters: Jupiter, 44.89″; Saturn, 18.08″, rings, 42.12″. Mars, 18.21″, and Venus 20.37″. At 6 am. Mars also displays an enlargement showing surface detail. The ” symbol means seconds of arc (1/3600th of a degree.) 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 August 26, 2020. The night ends on the left with sunrise on the 27th. Comet NEOWISE is now 8th magnitude, almost too faint for binoculars. Click on the image to enlarge. Created using my LookingUp program.

08/25/2020 – Ephemeris – The Great Andromeda Galaxy will collide with the Milky Way someday

August 25, 2020 Comments off

This is Ephemeris for Tuesday, August 25th. Today the Sun will be up for 13 hours and 33 minutes, setting at 8:30, and it will rise tomorrow at 6:58. The Moon, at first quarter today, will set at 12:26 tomorrow morning.

Stars are at extreme distances compared to their sizes, even if one includes their planetary systems. Galaxies in a galaxy cluster are much closer with respect to their size. Astronomers have determined that our Milky Way galaxy will collide with the Great Andromeda galaxy, some two and a half million light years away, in about four and a half billion years. Don’t worry, it is very unlikely that any stars will collide during the event, though the solar system may be in for a wild ride. As the galaxies approach each other their beautiful spiral structures will begin to distort into tidal tails. Multiple passes of the two will occur before they will coalesce into one large elliptical galaxy. Other galaxies of the Local Group will join in over time.

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

Addendum

Colliding galaxies. Note the tidal tails. Credit: Hubble Legacy Archive, ESA, NASA.

View from Earth-Andromeda collision

Original caption: This illustration shows a stage in the predicted merger between our Milky Way galaxy and the neighboring Andromeda galaxy, as it will unfold over the next several billion years. In this image, representing Earth’s night sky in 3.75 billion years, Andromeda (left) fills the field of view and begins to distort the Milky Way with tidal pull. (Credit: NASA; ESA; Z. Levay and R. van der Marel, STScI; T. Hallas; and A. Mellinger)

08/24/2020 – Ephemeris – The Milky Way’s companion galaxies

August 24, 2020 Comments off

This is Bob Moler with Ephemeris for Monday, August 24th. Today the Sun will be up for 13 hours and 36 minutes, setting at 8:32, and it will rise tomorrow at 6:57. The Moon, 1 day before first quarter, will set at 11:51 this evening.

Not long after spiral nebulae were confirmed to be milky ways like ours or galaxies it was noticed that they were often found in bunches or clusters. One of the closest is the Virgo cluster seen in spring covering the constellation of Virgo and adjacent constellations. Our Milky Way Galaxy has two small satellite galaxies, the Clouds of Magellan first spotted by European eyes on his epic voyage, and belongs to a small cluster of galaxies along with the Great Andromeda galaxy. Perhaps 80 galaxies belong in all, most are small irregular dwarf galaxies, difficult to find and see. Our galaxy cluster is known simply as the Local Group. The galaxies of the Local Group interact gravitationally with each other.

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

Addendum

The Magellanic Clouds

The Small and Large Magellanic Clouds, these dwarf galaxies are seen best from the southern hemisphere. Credit: ESO S. Brunier.

The Great Andromeda Galaxy (M31). Image taken by Scott Anttila.

The Great Andromeda Galaxy (M31) is the largest member of the Local group with two of its satellite galaxies M32 to the left and M110 below-right. M31 can be spotted with the naked eye on fall and winter nights with the naked eye. Image taken by Scott Anttila.

M33, the Triangulum Galaxy

M33, the Triangulum Galaxy is the third largest galaxy in the Local Group after Andromeda and the Milky Way. It appears in the sky just east of the constellation of Andromeda in Triangulum the triangle. Though large it has a very low surface brightness making it hard to spot with binoculars or a telescope. Credit: Scott Anttila.

Virgo cluster

Some of the brighter members of the Virgo Cluster (of galaxies) as red ovals. The galaxies marked with an ‘M’ number are part of Charles Messier’s catalog. It took a telescope of 8 inch diameter for me to spot them. Someone with better vision, like Messier himself can spot them with a smaller telescope. Created using Cartes du Ciel (Sky Charts).

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.

 

08/20/2020 – Ephemeris – Where are we in the Milky Way Galaxy?

August 20, 2020 Comments off

This is Bob Moler with Ephemeris for Thursday, August 20th. Today the Sun will be up for 13 hours and 47 minutes, setting at 8:39, and it will rise tomorrow at 6:52. The Moon, 2 days past new, will set at 9:59 this evening.

If we are in the Milky Way galaxy, where are we, and where’s the center of this vast spiral? Astronomers have found that the Sun is located in an offshoot of a spiral arm called the Orion Spur and the naked eye stars in the sky are also in it. In the winter constellation of Orion we are looking away from the center of the galaxy. This time of year, looking to the south in the evening at the Teapot of stars that is Sagittarius we look toward the center, which we can’t see due to the gas and dust in the way. It’s there, just above the spout of the Teapot. It can be seen, but not in visible light. It was the first thing detected with a radio telescope and it can be seen in the infrared. But there, 27,000 light years away is a 4 million solar mass black hole at the center.

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

Addendum

The Sun in the nearby spiral arms of the Milky Way Galaxy

The Sun in the Orion Spur and the nearby spiral arms of the Milky Way Galaxy. The direction to the center of the galaxy is down. Click on the image to enlarge. Public Domain, Wikimedia.

Our place in the Milky Way.

Our place in the Milky Way. Note that we appear to be in a barred spiral galaxy. The arms are numbered and named. 3kpc is the 3 kiloparsec arm. 3kpc = 9,780 light years. The Sun is about 27,000 light years from the center. Credit NASA and Wikimedia Commons, via EarthSky.org.

Location of the center of the Milky Way and the Teapot of Sagittarius.

Location of the center of the Milky Way and the Teapot of Sagittarius. It is blocked by gas and dust in visible light.

Image of the heart of the Milky Way galaxy

An image from the Chandra X-ray Telescope of the center of the Milky Way. SGR A or Sagittarius A is a radio source. SGR A*, pronounced Sagittarius A Star, is the 4 million solar mass black hole in the center of the Milky Way Galaxy. Credit NASA.

08/19/2020 – Ephemeris – Looking at the naked-eye planets for this week

August 19, 2020 Comments off

This is Ephemeris for Wednesday, August 19th. Today the Sun will be up for 13 hours and 50 minutes, setting at 8:41, and it will rise tomorrow at 6:51. The Moon, 1 day past new, will set at 9:30 this evening.

Let’s look at the naked-eye planets for this week. Jupiter and Saturn are both low in the south-southeastern sky at 10 pm. Jupiter is the very bright one. To the left of it will be Saturn. They now seem to be separating a bit due to the Earth’s motion now, but they will cross paths in December. Both planets will be up most of the night with Jupiter setting first at 3:32 tomorrow morning and Saturn following at 4:15 am. The next planet visible will be Mars which will rise at 10:59 pm. Its now down to 51.3 million miles (82.6 million kilometers) away, as the Earth slowly overtakes it at the rate of about 3.0 million miles (4.9 million kilometers) a week. Brilliant Venus will rise at 3:09 am and is moving ahead of the Earth in its orbit.

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

Addendum

Jupiter and Saturn

Jupiter and Saturn with three constellations of the zodiac at 10 pm tonight August 19, 2020. Click on the image to enlarge. Created using Stellarium and GIMP.

Venus and Mars in the morning

Venus and Mars finder animation as seen at 6 am or about an hour before sunrise tomorrow morning August 20, 2020 with and without the lines delineating nearby constellations. Click on the image to enlarge. Created using Stellarium and GIMP.

Telescopic planets

The planets as seen in a telescope (north up) with the same magnification Apparent diameters: Jupiter, 45.64″; Saturn, 18.21″, rings, 42.42″. Mars, 17.17″, and Venus 21.81″. Mars also displays an enlargement showing surface detail. The ” symbol means seconds of arc (1/3600th of a degree.) 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 August 19, 2020. The night ends on the left with sunrise on the 20th. Click on the image to enlarge. Created using my LookingUp program.

08/18/2020 – Ephemeris – What is the Milky Way really like?

August 18, 2020 Comments off

This is Ephemeris for Tuesday, August 18th. Today the Sun will be up for 13 hours and 53 minutes, setting at 8:42, and it will rise tomorrow at 6:50. The Moon is new today, and won’t be visible.

Last Friday and yesterday we looked at what the Milky Way looked like, but what is the Milky Way really like. It’s hard to tell, being inside it. In the 1920s astronomers gradually learned that the Milky Way was similar to the great number of spiral nebulae seen outside of the milky band. It was a flattened pinwheel of stars, gas and dust. At first they and the Milky Way were called island universes because until then it was thought that the Milky Way was the entire universe. The word for the Milky Way and those other structures is galaxy. The word galaxy is related to the Greek word for milk. Astronomers in the latter half of the 20th century using radio telescopes were able to trace out the clouds of gas that give our galaxy its spiral structure.

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

Addendum

Herschel's Universe

The shape of the universe (Milky Way) as measured by William Herschel by counting stars in the eyepiece fields of his telescope pointed in various directions. The large indent on the right is caused by the Great Rift, clouds of gas and dust that block the light of the stars behind it, not the lack of stars in that direction that he thought. The Great Rift is easily seen in the summer sky running through the Milky Way.

1950's radio map of the Milky Way Galaxy

1950’s radio map of the Milky Way Galaxy. The original source is for the map is The galactic system as a spiral nebula Oort, J. H.; Kerr, F. J.; Westerhout, G. MNRAS 118, (1958) p. 379.

Our place in the Milky Way.

Our place in the Milky Way. Note that we appear to be in a barred spiral galaxy. The arms are numbered and named. 3kpc is the 3 kiloparsec arm. 3kpc = 9,780 light years. The Sun is about 27,000 light years from the center. Credit NASA and Wikimedia Commons, via EarthSky.org.

M101

One of the many spiral nebulae visible, namely the Pinwheel Galaxy, M101 near the handle of the Big Dipper. Credit Scott Anttila.