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04/26/2021 – Ephemeris – There’s a full supermoon tonight

April 26, 2021 Comments off

This is Ephemeris for Monday, April 26th. Today the Sun will be up for 14 hours and 2 minutes, setting at 8:41, and it will rise tomorrow at 6:38. The Moon, at full today, will rise at 8:19 this evening.

The full moon tonight is the full Pink Moon, and a supermoon. As down as I am about full moons due to the fact that they light up the sky and flood out the dimmer objects in the sky, I once in a while stop and view it. The time of the full moon is 11:31 tonight, so when it rises tonight we will be looking at the moon from very nearly the direction of the Sun, so there will be few shadows to be had. The crater Tycho is near the bottom or south end of the moon and has long rays of tiny ejecta craters. The full moon is the best time to see these rays, which are easily visible in binoculars, through which Tycho itself looks like a bright dot. In telescopes Tycho looks like a small bright crater with a dark ring around it. The full moon is super bright. It’s daytime over there.

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

Addendum

High contrast full Moow
The full Moon 7 hours before it was officially full. The contrast was greatly enhanced to bring out Tycho’s ray system. The crater Tycho is at the south part of the Moon and appears bright with a dark ring around it. Credit Bob Moler.
Tycho and Kepler
Tycho and Kepler. Artist for Tycho: Eduard Ender (1822-1883). Artist for Kepler, unknown. Source: Wikipedia

Tycho Brahe and Johannes Kepler are inexorably linked in astronomical history. Tycho was famously stingy with the results of his observations. It was only after his death that Kepler was able to have access to them. Mars was the planet that was hardest to model in both the Ptolemaic geocentric and Copernican heliocentric universes, since both assumed the planetary orbits were circular. So both resorted to epicycles in an attempt to tweak their models in an attempt to fit with observational reality.

Both Tycho and Kepler have craters named for them on the Moon. Tycho gets a splashy crater on the southern part of the Moon. Kepler, however, gets a small crater on the plains of Oceanus Procellarum west of the crater Copernicus on the left side of the Moon, as we see it

03/08/2021 – Ephemeris – 45 years ago today I saw and photographed Comet West!

March 8, 2021 Comments off

This is Bob Moler with Ephemeris for International Women’s Day, Monday, March 8th. Today the Sun will be up for 11 hours and 32 minutes, setting at 6:40, and it will rise tomorrow at 7:05. The Moon, 3 days past last quarter, will rise at 5:34 tomorrow morning.

On this day 45 years ago, in 1976, during the first year of these Ephemeris programs I was able to report on, observe and photograph the brightest comet I had seen up till that time: Comet West. It was not supposed to be a bright comet, but as it rounded the Sun, it began to brighten spectacularly. Later I found out that it’s nucleus broke into several fragments, liberating a great quantity of gas and dust. It turned out to be a very dusty comet which ended up in a broad and bright tail. It was going to be visible before sunrise, and this was the first morning in a while it was clear. Even before the head of the comet rose, the tail could be seen rising in the east. I was able to get several photographs of this wonderful comet!

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

Addendum

Comet West at 6 am, March 8, 1976

Comet West, C/1975 V1, as photographed by me at about 6 am, March 8, 1976. The wide, curved dust tail is most prominent with the narrow blue ion tail pointed more directly at the rising Sun. The small summer constellation of Delphinus the dolphin is to the upper right. The diamond shape of stars at the front of the dolphin’s body is an asterism called Job’s Coffin.

In the image above is tilted about 45 degrees to the horizon in the lower left due to the fact that it was on an equatorial mount, where up and down is north and south in the sky, horizontally is east and west. It’s cocked 45 degrees to the horizon because we are at 45 degrees latitude. Actually the angle is 90 – your latitude which around here is 90 – 45 = 45.

I got up early in the morning of March 8th 1976. I had my telescope mount outside because it takes awhile to set it up to true north and everything. The telescope and camera that mounts on it were taken inside. I just left it there covered with a tarp and wasn’t observing too much that winter. When I got up in wee hours of the morning of the eighth I found out that my telescope mount was buried in the middle of a snowdrift, so I had to dig it out. As I was digging it out I looked to the east and saw the tail of the comet rising before the head did. I then redoubled my efforts and got everything set up so I could take photographs of the comet.

I had built a small telescope a few years before for a solar eclipse as a kind of contingency camera in case my automatic cameras I had built didn’t work. It was a 108 mm f/6 reflecting telescope that I attached a camera back to and took some minute or two long exposures that way. I then realized that the sky was getting brighter, so I quickly switched, and took a couple of wide angle pictures with the 50 mm lens with tracking. That’s one of them above that shows the lovely comet with the long tail.

Comet West 108mm f/6

Comet West taken through the 108 mm f/6 telescope around 5:30 am, March 8, 1976 by a much younger me.

12/24/2020 – Ephemeris – Was the Star of Bethlehem a triple conjunction of Jupiter and Saturn in 7 BC?

December 24, 2020 Comments off

This is Bob Moler with Ephemeris for Christmas Eve, Thursday, December 24th. Today the Sun will be up for 8 hours and 48 minutes, setting at 5:07, and it will rise tomorrow at 8:18. The Moon, 3 days past first quarter, will set at 3:50 tomorrow morning.

For many years the most popular theory for the origin of the Star of Bethlehem was a triple conjunction of Jupiter and Saturn in 7 BC. This is because, due to Earth’s motion, other planets from our view point seem to reverse course when we pass them or are being passed in the circular racetrack of the solar system. When Jupiter and Saturn approach each other just before they go retrograde or reverse course they have a chance to pass each other, backup and pass again, then going forward to pass a third time. Jupiter and Saturn did that last in 1981, so it’s a reasonably rare occurrence, especially when it happens in front of the constellation Pisces which was supposedly related to the Jews.

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

Addendum

Jupiter-Saturn Triple Conjunction

Jupiter and Saturn pass each other three times from May to December in 7 BC against the constellation of Pisces. Reload the page to replay the animation. Created using Cartes du Ciel (Sky Charts) and GIMP.

Retrograde motion explained

Retrograde motion illustrated using Mars in 2018. Created using my LookingUp program.

 

 

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.

 

03/02/2020 – Ephemeris – Greek use of the first quarter Moon

March 2, 2020 Comments off

Ephemeris for Monday, March 2nd. Today the Sun will be up for 11 hours and 14 minutes, setting at 6:32, and it will rise tomorrow at 7:15. The Moon, at first quarter today, will set at 2:39 tomorrow morning.

The Moon is at first quarter at 2:57 this afternoon. The ancient Greek philosopher/astronomer Aristarchus* tried to determine the distance to the Sun by observing the Moon at exactly first quarter and measuring the angle between it and the Sun. If we see the Moon at exactly first quarter when the sunrise line called the terminator cuts the Moon exactly in half then the angle at the Moon between the Sun and the Earth is a right or 90 degree angle. If we, on the Earth at that same instant were able to measure the angular distance between the Moon and the Sun. we could theoretically calculate the distance to the Sun. He was correct about the Moon’s distance, but calculated the Sun was at only about 10% of its actual distance.

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

* In the actual broadcast program I erroneously credited the later Greek astronomer Hipparchus.

Addendum

Quarter Mon method of determining the Sun's distance

Quarter Moon method of determining the Sun’s distance by Aristarchus. Credit: andonee

12/27/2019 – Ephemeris – A Decade of astronomical and space firsts

December 27, 2019 Comments off

Ephemeris for Friday, December 27th. Today the Sun will be up for 8 hours and 49 minutes, setting at 5:08, and it will rise tomorrow at 8:19. The Moon, 1 day past new, will set at 6:38 this evening.

The 2010s were quite a decade in astronomy and space. 24 years ago the first exoplanet, that is planet orbiting another star, was discovered: 51 Pegasi b. As of December 8th the number of confirmed exoplanets stands at 4,104. At mid decade we got a close look at the dwarf planet Pluto and its moons, and early this year at the distant object temporarily called Ultima Thule. Early this year the Event Horizon Telescope consortium released the image of a black hole over 50 million light years away. Also the LIGO and Virgo gravitational wave observatories detected two neutron stars colliding which set off a frenzy of activity by astronomers who viewed the aftermath from gamma rays to microwaves.

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

Addendum

Kepler Spacecraft. Credit NASA.

Kepler Spacecraft studied a single patch of sky for several years and has discovered the bulk of the exoplanets. Credit NASA.

Pluto

Enhanced color portrait of Pluto by the New Horizons spacecraft. Credit: NASA/JHUAPL/SwRI

First closeup of Ultima Thule

486958 Arrokoth original dubbed Ultima Thule by the New Horizons team on approach combining low resolution image with the high resolution monochromatic image shows the body in almost true color. Credit NASA/JHAPL/SWRi

Black hole in M87

The first image of the black hole in M87. Credit Event Horizon Telescope.

Neutron Star Collision GW 170817 timeline

Neutron Star Collision GW 170817 timeline. Horizontal axis in seconds (exponential). Click on chart to enlarge. From the High Energy Stereoscopic System website.

07/22/2019 – Ephemeris – Apollo 11 heads home

July 22, 2019 Comments off

Ephemeris for Monday, July 22nd. Today the Sun will be up for 15 hours and 1 minute, setting at 9:19, and it will rise tomorrow at 6:19. The Moon, 2 days before last quarter, will rise at 12:27 tomorrow morning.

50 years ago after a bit more than 2 hours working on the surface of the Moon, Neil Armstrong and Buzz Aldrin climbed back into the Lunar Module to stow the 48 pounds of samples they had taken and to rest up for the return trip to the Command Module and Mike Collins circling above them. After docking, they transferred the samples to the command module and jettisoned the LM. Then they fired the Service Module engine for 2 and a half minutes to send them back to Earth, and landing them in the Pacific Ocean on July 24th. Not knowing if they were contaminated by lunar pathogens, the crew was quarantined for 21 days. The crew was released from Quarantine on August 10th.

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

Addendum

Lunar lander’s ascent module approaching the command module with Earth in the distance. Credit NASA.

The crew in a like raft in bio contamination suits after splashdown.. Credit NASA.

Left to right Neil Armstrong, Michael Collins, Buzz Aldrin accept greeting form President Nixon on the USS Hornet. Credit NASA.

07/19/2019 – Ephemeris – 50 years ago tomorrow humankind set foot on the Moon

July 19, 2019 Comments off

Ephemeris for Friday, July 19th. Today the Sun will be up for 15 hours and 7 minutes, setting at 9:22, and it will rise tomorrow at 6:16. The Moon, 3 days past full, will rise at 11:14 this evening.

On this day, 50 years ago the combined Apollo 11 spacecraft Command and Service module with attached Lunar Module dropped into orbit of the Moon. The crew spotted a glow coming from the Aristarchus region, still on the night side of the Moon. Armstrong and Aldrin entered the LM to power it up and to get it ready for landing. The next day they undocked from the Command Module and began their 2 hour 33 minute descent to the Moon’s surface. As they neared the surface The astronauts found out they were going to miss the planned landing area and would land in a more boulder strewn area. Armstrong took control and guided the LM to a safe landing with less than 30 seconds of fuel remaining. The Eagle had landed.

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

Addendum

Crew of Apollo 11

Left to right Neil Armstrong, Mission Commander; Michael Collins, Command Module Pilot; and Buzz Aldrin, Lunar Module Pilot. Credit: NASA.

Apollo 11 launch

The Saturn V for the Apollo 11 mission lifts of from Pad 39A. Credit: NASA.

Aldrin with the PSEP instrument looking back at the LM. Credit NASA/Neil Armstrong.

Lunar Reconnaissance Orbiter image of the Apollo 11 landing area. Compare the location od the objects in the picture above with this image.  The flag was blown down by the lift off of the Ascent module when the Astronauts left the Moon. Credit NASA/LRO.

07/16/2019 – Ephemeris – 50 years ago today the Apollo mission left for the Moon

July 16, 2019 Comments off

Ephemeris for Tuesday, July 16th. Today the Sun will be up for 15 hours and 12 minutes, setting at 9:25, and it will rise tomorrow at 6:13. The Moon, at full today, will rise at 9:30 this evening.

50 years ago today at 11:32 a.m. Eastern Daylight Time the most powerful rocket ever built roared into life. The Saturn V, a three stage rocket, 363 feet tall, which in turn launched two spacecraft, the Command and Service modules, and the Lunar Module, and three astronauts on their journey to destiny, Neil Armstrong, Edwin (Buzz) Aldrin, and Michael Collins. It was the start of the Apollo 11 mission. It happens that tonight the namesake of the rocket, the planet Saturn is to the right of the Moon. At launch the Moon was two days old, a thin crescent in the west that evening. Four days later they would be orbiting the Moon, and Armstrong and Aldrin would be descending to the Moon’s surface.

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

Addenda

Apollo 11

Crew of Apollo 11

Left to right Neil Armstrong, Mission Commander; Michael Collins, Command Module Pilot; and Buzz Aldrin, Lunar Module Pilot. Credit: NASA.

Apollo 11 launch

The Saturn V for the Apollo 11 mission lifts of from Pad 39A. Credit: NASA.

The Moon and Saturn tonight

The Moon and Saturn tonight, 11 p.m. July 16, 2019. In reality the Moon will be so bright that Saturn will be almost overwhelmed. Created using Stellarium.

Here’s an excellent podcast series from the BBC:  13 Minutes to the Moon.

Partial Lunar Eclipse

The partial lunar eclipse today is not mentioned in the program because it is not visible locally.

Partial Lunar Eclipse of July 16, 2019. Click on image to enlarge. Credit NASA/GSFC/F. Espenak.

07/15/2019 – Ephemeris – The Apollo 1 tragedy

July 15, 2019 Comments off

Ephemeris for Monday, July 15th. Today the Sun will be up for 15 hours and 14 minutes, setting at 9:25, and it will rise tomorrow at 6:12. The Moon, 1 day before full, will set at 5:48 tomorrow morning.

On January 27th, 1967 the crew of Apollo 1 were running a dress rehearsal of their upcoming launch. On board were Gus Grissom, veteran of the Mercury and Gemini programs, Ed White the first American to walk in space on Gemini 4, and rookie astronaut Roger Chaffee from my home town of Grand Rapids, Michigan. Five and a half hours after the test started one of the crew called out “Fire in the cockpit”. In a very few minutes the astronauts were dead. They were running in a pure oxygen atmosphere at a bit above atmospheric pressure and a spark may have ignited the flammable materials in the spacecraft. The accident delayed the program nearly 2 years as the capsule was redesigned.

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

Addendum

Apollo 1 crew

Left to right: Virgil I. (Gus) Grissom, veteran of the second Mercury flight and Gemini 3, the first manned Gemini flight; Edward H. White first American space walker on Gemini 4, and rookie Roger B. Chaffee. Credit: NASA.

Apollo 1 spacecraft after the fire

The outside of the Apollo 1 capsule after thr fire that took the three astronaut’s lives. Credit: NASA.