SpaceWatchtower

Sunday, April 6, 2025

60 Years Ago: Arthur C. Clarke's Vision of Geostationary Satellites Comes True

Engineers Stanley R. Peterson (left) and Ray Bowerman check-out Intelsat I or Early Bird prior to launch from Complex 17a, Cape Kennedy (now Cape Canaveral), Florida on 1965 April 6. (Image Sources: NASA, Wikipedia.org, By NASA - Great Images in NASA Description, Public Domain, https://commons.wikimedia.org/w/index.php?curid=686174)

By Glenn A Walsh

Reporting for SpaceWatchtower

April marks the 60^th anniversary of the orbiting of Intelsat I, the first commercial, geostationary satellite. Also known as Early Bird, the geostationary satellite was popularized 20 years earlier by the famous science-fiction writer and scientist Arthur C. Clarke.

Intelsat I entered a geostationary orbit on 1965 April 6, as the first commercial communications satellite to achieve such an orbit. After some maneuvering, the satellite settled in an orbit over the Atlantic Ocean at 28 degrees West Longitude, where it began commercial service.

Constructed by the Space and Communications Group of Hughes Aircraft Company (later known as the Hughes Space and Communications Company and now known as the Boeing Satellite Systems). It was built for COMSAT (Communications Satellite Corporation), which activated the satellite on 1965 June 28.

Early Bird was based on a series of Syncom satellites built for NASA by the Hughes Aircraft Company. These experimental satellites proved the concept of communications by geostationary satellites.

Early Bird helped to provide live television coverage of the splashdown of the NASA Gemini 6 crewed spacecraft, in December of 1965. Early Bird also was one of the satellites used for the 2-hour Our World, the first live multi-national, multi-satellite television broadcast on 1967 June 25.

Early Bird provided commercial communications services for 4 years and 4 months, ending regular service in January of 1969. It was briefly reactivated in June of 1969 (until 1969 August) to assist in the mission of the NASA Apollo 11 (which was the first mission to land 2 astronauts on the Moon), due to the failure of the then-Atlantic Ocean Intelsat satellite.

Early Bird was the first satellite to provide direct and nearly-instantaneous television, telephone, and telefacsimile transmissions between North America and Europe.

Early Bird was also briefly reactivated for the 25^th anniversary in 1990. Today, Early Bird remains in orbit, inactive as a communications satellite.

A geostationary orbit is also known as a geosynchronous equatorial orbit (GEO). The height above the Earth or altitude of such an orbit is 22,236 statute miles / 35,786 kilometers.

When placed in such an orbit, a satellite orbits the Earth at the same rate of speed as the rotation rate of the Earth. Consequently, the satellite seems to remain fixed in one location above the Earth, even though it is always moving in orbit around the Earth. To match the Earth's rotation rate, the satellite travels at approximately 7,000 statute miles per hour / 11,300 kilometers per hour.

It was in a 1945 paper titled, “Extra-Terrestrial Relays”, that famous science-fiction writer and scientist Arthur C. Clarke proposed using satellites in geostationary orbit as a way to relay radio messages around the world, without the need of cables under the oceans. The proposal was published in the 1945 October issue of the magazine, Wireless World.

In his 1945 article, he discussed the problems of long-distance radio and telephone communications. He maintained that the ionosphere distorted long-distance radio signals, and television signals could not be transmitted by long-distances, without expensive relays about every 50 miles. Arthur C. Clarke wrote, “A relay chain several thousand miles long would cost millions, and transoceanic services would still be impossible”.

He proposed converting the German V2 rockets to more powerful, radio-controlled rockets which could lift “a second moon” into orbit. In addition to relaying communications transmissions, he also suggested that this could be a “space station” where astronomers and other scientists could study astronomy, physics, and meteorology.

In the article, he proposed the launch of a series of GEO communications satellites, which would be equi-distant from one-another around the globe. For complete coverage of the Earth, these satellites would be linked to one-another and to the Earth by radio or optical beams (there was no fully functioning laser until 15 years later, on 1960 May 16, although Albert Einstein established the theoretical foundations for a laser in a 1917 scientific paper).

Internet Links to Additional Information ---

Intelsat I / Early Bird: Link >>> https://en.wikipedia.org/wiki/Intelsat_I

Arthur C. Clarke: Link >>> https://en.wikipedia.org/wiki/Arthur_C._Clarke

"Clarke Suggests Geosynchronous Orbit": Link >>> https://ethw.org/Clarke_Suggests_Geosynchronous_Orbit

"The 1945 Proposal by Arthur C. Clarke for Geostationary Satellite Communications";

Link >>> https://lakdiva.org.lk/clarke/1945ww/

Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss

"60 Years Ago: Arthur C. Clarke's Vision of Geostationary Satellites Comes True"

Sunday, 2025 April 6.

Artificial Intelligence not used in the writing or production of this article.

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gaw

Glenn A. Walsh, Informal Science Educator & Communicator (For more than 50 years! - Since Monday Morning, 1972 June 12):
Link >>> http://buhlplanetarium2.tripod.com/weblog/spacewatchtower/gaw/
Electronic Mail: < gawalsh@planetarium.cc >
Project Director, Friends of the Zeiss: Link >>> http://buhlplanetarium.tripod.com/fotz/
SpaceWatchtower Editor / Author: Link >>> http://spacewatchtower.blogspot.com/
Formerly Astronomical Observatory Coordinator & Planetarium Lecturer, original Buhl Planetarium & Institute of Popular Science (a.k.a. Buhl Science Center), America's fifth major planetarium and Pittsburgh's science & technology museum from 1939 to 1991.
Formerly Trustee, Andrew Carnegie Free Library and Music Hall, Pittsburgh suburb of Carnegie, Pennsylvania, the fourth of only five libraries where both construction and endowment funded by famous industrialist & philanthropist Andrew Carnegie.
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh: Link >>> http://www.planetarium.cc Buhl Observatory: Link >>> http://spacewatchtower.blogspot.com/2016/11/75th-anniversary-americas-5th-public.html
* Adler Planetarium, Chicago: Link >>> http://adlerplanetarium.tripod.com
* Astronomer, Educator, Optician John A. Brashear: Link >>> http://johnbrashear.tripod.com
* Andrew Carnegie & Carnegie Libraries: Link >>> http://www.andrewcarnegie.cc

* Other Walsh-Authored Blog & Web-Sites: Link >>> https://buhlplanetarium.tripod.com/gawweb.html

Monday, January 27, 2025

Coordinated Lunar Time Zone for the Moon

This photograph shows the Royal Greenwich Observatory in Greenwich Park in south-east London. Earth time zones were developed from the Prime Meridian, here at Greenwich. Now, scientists are developing a time zone for the Earth;s Moon.

(Image Source: Wikipedia.org, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=334711)

By Glenn A. Walsh

Reporting for SpaceWatchtower

Time on the Moon is about to become “coordinated”. Both the American Government and the European Union are studying how to establish Coordinated Lunar Time. And, Coordinated Lunar Time would also lead to a separate Global Positioning System (GPS) specifically for the Moon.

Coordinated Lunar Time will be determined by the weighted averaging of atomic clocks on the Moon's surface. This is similar to how standard time is determined on Earth. This project includes the consideration of where on the Moon to place the atomic clocks.

Such a new time standard was first proposed by the European Space Agency (ESA) in early 2023. In April of 2024, the White House asked NASA [through the agency's Space Communication and Navigation (ScaN) Program] to work with U.S. and international scientific agencies for the purpose of establishing Coordinated Lunar Time.

The title of the new lunar time zone comes from Coordinated Universal Time, the Earth time based at the Prime Meridian, established by Great Britain at the beginning of their naval dominance. The Prime Meridian was centered at Britain's Royal Greenwich Observatory, located in Greenwich Park in south-east London.

Today, Coordinated Universal Time (previously known as Greenwich Mean Time and Greenwich Civil Time) is the standard time used by scientists and navigators. All other standard time zones throughout the world are derived from Coordinated Universal Time. Each of the other 23 hourly time zones are a certain number of hours ahead or behind the time zone at the Prime Meridian (occasionally, a half-hour time zone exists, as for the Canadian province of Newfoundland).

Space missions to the Moon now use either Coordinated Universal Time or the time zone of origin of the space mission. This time could be Houston time (Central Time Zone at NASA's Johnson Space Center), Los Angeles time (Pacific Time Zone for Pasadena's Jet Propulsion Laboratory of the California Institute of Technology), Moscow time (for Russian missions), China Standard Time (for Chinese missions), or Indian time (for missions from India).

As more nations and private companies send missions to the Moon, there needs to be a common time zone, that all space missions use, to avoid confusion.

Further, time passes on the Moon, and in lunar orbit, at different rates. And, these times also differ from how time passes on the Earth or in Earth orbit.

This is due to the fact that clocks tick more slowly when in Earth orbit, than clocks on the ground. This is also true for the Moon and lunar orbit.

Also, clocks on the Moon tick fractionally faster than clocks on Earth, because the Moon has a much less gravitational attraction than gravity on the Earth. Gravity on the Moon is about 1/6 the attraction of gravity on Earth.

Plus, scientists have to consider that the Moon orbits the Earth. So, as the Earth's gravity is strong enough to keep the Moon in Earth orbit, the Earth's gravity can also have an affect on lunar time.

The lunar time standard being proposed would solve these types of time-keeping issues. According to Arati Prabkahar, who was the Director of the White House Office of Science and Technology Policy and Science Advisor to the President (during much of the Administration of U.S. President Joe Biden), lunar time would currently "appear to lose on average 58.7 microseconds per Earth-day and come with other periodic variations that would further drift Moon time from Earth time"

For perspective, consider that a hummingbird's wings flap at a rate of about 50 times per second. Each flap has a duration of about 0.02 second or 20/000 microseconds.

This is all due to the effects of relativity. Albert Einstein's General Theory of Relativity states that gravity affects time, or space-time as he referred to it. Dr. Einstein's research showed that time does not flow uniformly everywhere. Hence, scientists must grapple with all of the variations in time at different locations, to ensure that clocks and GPS work properly in any locality.

Once developed, this new time standard is meant to be used by all nations and companies sending missions to the Moon. Initially, it will be developed and instituted through a collaboration of members of the Artemis Accords. The Artemis Accords (named for the Artemis mission to send U.S. astronauts, including the first woman and the first astronaut of-color, back to the Moon) are a series of non-binding, multilateral arrangements between the United States and other governments on Earth, which elaborates on the norms expected by space-faring nations.

There are four key features of this new time standard, initially:

Traceability back to Coordinated Universal Time.
Accuracy sufficient for navigation and science.
Resilience to disruptions.
Scalability to potential environments beyond the Earth – Moon system.

In August of 2024, the U.S. National Institute of Standards and Technology (NIST) released a draft of the proposed standard. The draft focuses on the framework and mathematical model, which takes into account the gravitational differences on the Moon.

This draft was published in The Astronomical Journal, a leading scientific publication.

A unified time standard for the Moon, and possibly including other celestial bodies, is expected by 2026, as requested by the Biden Administration.

Internet Links to Additional Information ---

The Moon of Earth: Link >>> https://en.wikipedia.org/wiki/Moon

Timekeeping on the Moon: Link >>> https://en.wikipedia.org/wiki/Timekeeping_on_the_Moon

NASA News Release: "NASA to Develop Lunar Time Standard for Exploration Initiatives":

Link >>> https://www.nasa.gov/general/nasa-to-develop-lunar-time-standard-for-exploration-initiatives/

NIST News Release: "What Time Is It on the Moon?":

Link >>> https://www.nist.gov/news-events/news/2024/08/what-time-it-moon

Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss

"Coordinated Lunar Time Zone for the Moon"

Monday, 2025 January 27.

Artificial Intelligence not used in the writing or production of this article.

* Other Walsh-Authored Blog & Web-Sites: Link >>> https://buhlplanetarium.tripod.com/gawweb.html

Friday, September 20, 2024

Fall Begins at Equinox Sunday Morning

This diagram shows the position of the Earth, in relation to the Sun, at the time of the Autumnal Equinox, as well as the other equinox and solstices of the year.

[Graphic Source: ©1999, Eric G. Canali, former Floor Operations Manager of the original Buhl Planetarium and Institute of Popular Science / Buhl Science Center (America's 5th major planetarium & Pittsburgh's science and technology museum from 1939 to 1991) and Founder of the South Hills Backyard Astronomers amateur astronomy club. Permission granted for non-profit use only, with credit to author.]

By Glenn A. Walsh

Reporting for SpaceWatchtower

The Autumnal Equinox Sunday morning marks the end of the season of Summer and the beginning of Fall or Autumn in Earth's Northern Hemisphere. In the Southern Hemisphere, this marks the transition from Winter to Spring.

The Autumnal Equinox (also known as the September Equinox), the end of Summer and the beginning of the season of Autumn or Fall in Earth's Northern Hemisphere, occurs Sunday Morning, 2024 September 22 at 8:44 a.m. Eastern Daylight Saving Time (EDT) / 12:44 Coordinated Universal Time (UTC). In the Southern Hemisphere, this moment marks the astronomical beginning of the season of Spring.

Autumn or Fall continues in the Northern Hemisphere, and Spring in the Southern Hemisphere, until the December Solstice: Saturday Morning, 2024 December 21 at 4:21 a.m. Eastern Standard Time (EST) / 9:21 UTC. At the moment of the December Solstice, Winter begins in the Northern Hemisphere and Summer begins in the Southern Hemisphere.

The approximate and traditional mid-way point between the Autumnal Equinox and the Winter Solstice comes in the vicinity of October 31 (All-Hallows Eve or Halloween) / November 1 (All-Saints Day) / November 2 (All-Souls Day): the Astronomical Cross-Quarter Day of Samhain or All-Hallowsmas. The actual November Cross-Quarter Day will be Wednesday Afternoon, 2024 November 6 at .5:21 p.m. EST / 22:21 UTC. The approximate one-week discrepancy between the dates of the traditional and actual Cross-Quarter Day is due to the fact that the traditional date of Samhain was fixed on October 31, when the Julian Calendar was still in use.

In ancient times, a calendar season was considered the time between one Cross-Quarter Day and the next Cross-Quarter Day. So, Autumn was considered the time between August 1 (Lughnasadh or Lammas Day), which was the traditional beginning of the wheat harvest, to October 31 (Samhain). Samhain actually means “Summer's end” as the Celtic calendar only considered two main seasons: Summer and Winter.

The Celtic peoples of Ireland began celebrations on Samhain in the 5^th century B.C. Samhain was considered by the Celtics and Druids on the British Isles as the end of the old year, with the following day the beginning of the New Year. In A.D, 835, the Roman Catholic Church named November 1 All-Saints Day with the previous day becoming All-Hallows Eve or Halloween, the eve or evening before All-Saints Day.

It is believed that in ancient times the Pleiades Star Cluster, also known as the Seven Sisters, culminated (climbed to the cluster's highest point in the sky) around Midnight local time on or near Samhain. Samhain and Pleiades Culmination would have occurred together around A.D. 11^th and 12^th centuries before the Gregorian Calendar was instituted. For the Pleiades Culmination to occur during the dark time of the year's end, many peoples felt this was a time to honor the dead. Although today Pleiades Culmination occurs on November 21, the Pleiades still can be seen high in the sky around local Midnight on Halloween, weather-permitting.

On the day of the Equinox, the Sun appears directly overhead at local Noon on the Equator. At the moment of Equinox, the Northern and Southern Hemispheres of Earth are illuminated equally. And, the time of Equinox is the only time when the Earth Terminator (dividing line on Earth between daylight and darkness) is perpendicular to the Equator.

This, and the reason for seasons on Earth in the first place, is due to the fact that Earth rotates on its axis, which is tilted at an approximate 23.44-degree angle from the Ecliptic, the plane of the Earth's orbit around the Sun. As the Earth revolves around the Sun, this axial tilt causes one hemisphere of the planet to receive more direct solar radiation during that hemisphere's season of Summer and much less direct solar radiation about a half-year later during that hemisphere's season of Winter. As mentioned, during an Equinox [in the Northern Hemisphere: about half-way between Summer and Winter (Autumnal Equinox), and about half-way between Winter and Summer (Vernal Equinox)] both planetary hemispheres receive an equal amount of solar radiation.

Although "Equinox" in Latin means equal-night, the day of the Equinox does not actually have an equal amount of daylight and nightfall, as it appears on the Earth's surface. If the Sun was just a pin-point of light in our sky, as all other stars appear, day and night would be equal.

But, because the Sun is a disk, part of the Sun has risen above the horizon before the center of the Sun (which would be the pin-point of light); so there are extra moments of light on the Equinox. Likewise, part of the Sun is still visible, after the center of the Sun has set.

Additionally, the refraction of sunlight by our atmosphere causes sunlight to appear above the horizon, before sunrise and after sunset.

Each year, September 25 or 26 marks the Equilux ("equal-light"), the actual day with equal hours and minutes of the Sun above the horizon, and equal hours and minutes of the Sun below the horizon. The Equilux occurs twice each year, approximately 3-to-4 days before the Vernal Equinox, when Spring begins, and 3-to-4 days after the Autumnal Equinox, after Autumn or Fall has begun.

An urban legend that has been making the rounds for decades has it that eggs can be stood on their ends only during an Equinox, whether the Vernal Equinox in the Spring or the Autumnal Equinox in the Fall. This is completely false. Depending greatly on the size and shape of the particular egg, eggs can be stood on their ends any day of the year! Astronomy has nothing to do with whether an egg can stand on its end. If an egg can stand on its end on the Equinox (and, due to the shape and size of some eggs, this is not even possible), it can stand the same way any other day of the year.

In the last few years, with the help of the Internet and Social Media, another urban legend has become prevalent. Now it is claimed that brooms can stand, on their own, on their bristles, only on an Equinox day. This is also false. Again, as with eggs, if a broom can stand on its bristles by itself (this usually only works with newer brooms, with more stiff and even bristles) on an Equinox, it can do so any day of the year!

In China, Vietnam, Korea, Japan, and other nations in East and Southeast Asia, a popular harvest festival is celebrated on the date close to the Autumnal Equinox of the Solar Cycle, as well as close to the Harvest Moon. This Mid-Autumn Festival / Moon Festival dates back more than 3,000 years to Moon worship in China's Shang Dynasty.

Again, as Western Cultures consider September the beginning of Autumn (meteorologists and climatologists consider September 1 the beginning of Meteorological Autumn), the ancients often termed this as "Mid-Autumn". By this reckoning, Autumn actually began at the traditional Cross-Quarter Day of August 1 (when some harvesting actually begins) and ends at the traditional Cross-Quarter Day of All-Hallow's Eve, also known as Halloween.

On the Chinese Han Calendar, the Mid-Autumn Festival falls on the 15th day of the 8th month (on a day between September 8 and October 7 in our Gregorian Calendar). This usually falls on the night of a Full Moon, the Harvest Moon. This year, the Harvest Moon occurred on Tuesday Evening, 2024 September 17 at 10:34 p.m. EDT / September 18, 2:34 UTC. This particular Harvest Moon was also a so-called “Super-Moon” (Lunar Perigee Full Moon), which experienced a shallow Partial Lunar Eclipse / Partial Eclipse of the Moon.

September 22 is designated as Falls Prevention Awareness Day.

Internet Links to Additional Information ---

Mid-Autumn Festival / Moon Festival: Link >>> https://en.wikipedia.org/wiki/Mid-Autumn_Festival

Cross-Quarter Day: Link >>> https://en.wikipedia.org/wiki/Wheel_of_the_Year

Autumnal Equinox: Link >>> http://scienceworld.wolfram.com/astronomy/AutumnalEquinox.html

Season of Autumn or Fall: Link >>> http://en.wikipedia.org/wiki/Autumn

Equinox: Link >>> http://en.wikipedia.org/wiki/Equinox

Equilux: Link >>> https://darkskydiary.wordpress.com/2010/03/20/equinox-equilux-and-twilight-times/

Earth's Seasons: Link >>> http://en.wikipedia.org/wiki/Season

Tilt of a planet's axis: Link >>> http://en.wikipedia.org/wiki/Axial_tilt

Urban legend of eggs and brooms standing on their own, only on an Equinox:
Link >>> http://www.snopes.com/science/equinox.asp

Falls Prevention Awareness Day: Link >>> https://nationaltoday.com/falls-prevention-awareness-day

Why Autumn Leaves Change Color: Link >>> http://spacewatchtower.blogspot.com/2013/10/colorful-fall-foliage-astronomy-affects.html

Related Blog-Post ---

"Partial Eclipse of Harvest Moon Tue. Night". Fri., 2024 Sept. 13.

Link >>> https://spacewatchtower.blogspot.com/2024/09/partial-eclipse-of-harvest-moon.html

Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss

"Fall Begins at Equinox Sunday Morning"

Friday, 2024 September 20.

Artificial Intelligence not used in the writing or production of this article.

* Other Walsh-Authored Blog & Web-Sites: Link >>> https://buhlplanetarium.tripod.com/gawweb.html

Friday, September 13, 2024

Partial Eclipse of Harvest Moon Tue. Night

The Harvest Moon often appears orange in color due to Rayleigh Scattering of sunlight from the Moon, which occurs whenever the Moon is near the horizon. The Harvest Moon always rises around the time of local sunset. (Image Sources: Wikipedia.org, By The original uploader was Roadcrusher at English Wikipedia. - Transferred from en.wikipedia to Commons by Khayman using CommonsHelper., CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=15755496)

By Glenn A. Walsh

Reporting for SpaceWatchtower

Tuesday evening, the Full Harvest Moon (which some would call the second so-called “Super-Moon” of 2024) comes with a bonus – a Partial Lunar Eclipse / Partial Eclipse of the Moon, which will be visible in most of the Western Hemisphere, Europe, Africa, and the Middle East. However, this Eclipse, which is safe to watch directly (weather-permitting), will be a very slight or shallow Lunar Eclipse.

Partial Lunar Eclipse / Partial Eclipse of the Moon

A Lunar Eclipse / Eclipse of the Moon is the only category of eclipses which is safe to view with the unaided eyes (one-power), binoculars, and a telescope.

A Live-stream Web-cast of this Partial Lunar Eclipse / Partial Eclipse of the Moon will be available for observers not in a region where the eclipse is visible in the sky, or where weather conditions make such an observation impossible (Internet link to this Live-stream near the end of this blog-post).

Everyone on the night or dark side of the Earth can view at least part of any Lunar Eclipse / Eclipse of the Moon, weather-permitting. People located where weather blocks direct view of the Eclipse, or who live in other parts of the world, would need to watch the eclipse on the Internet.

Here are the major stages of this Partial Lunar Eclipse / Partial Eclipse of the Moon –--

Late Tuesday Evening, 2024 September 17 / Wednesday Morning, 2024 September 18 -

[Eastern Daylight Saving Time (EDT) / Coordinated Universal Time (UTC)]

(Note that a Lunar Eclipse / Eclipse of the Moon is the only type of Eclipse where the times of Eclipse are the same world-wide, when using Coordinated Universal Time. Everyone on the dark or night side of Earth can view this Eclipse in the sky, weather-permitting.)

Penumbral Lunar Eclipse Begins --- Sept. 17, 8:41:07 p.m. EDT / Sept. 18, 0:41:07 UTC

Partial Lunar Eclipse Begins --- Sept. 17, 10:12:58 p.m. EDT / Sept. 18, 2:12:58 UTC

Primary Moon Phase: Full Moon – Harvest Moon --- Sept. 17, 10:34 p.m. EDT / Sept. 18, 2:34 UTC

Greatest Partial Lunar Eclipse --- Sept. 17, 10:44:18 a.m. EDT / Sept. 18, 2:44:18 UTC

Partial Lunar Eclipse Ends --- Sept. 17, 11:15:38 p.m. EDT / Sept. 18, 3:15:38 UTC

Penumbral Lunar Eclipse Ends --- Sept. 18, 12:47:27 a.m. EDT / Sept. 18, 4:47:27 UTC

At the time of Greatest Partial Lunar Eclipse / Partial Eclipse of the Moon on September 17, the Moon will be only 3.5 per-cent obscured by the Earth's Umbral shadow. The remaining portion of the Moon's surface will be well within the Penumbral shadow of the Earth. At this time, the Moon will appear as if a small chip, in the upper right portion of the Moon, has been removed, while the rest of the Moon may appear a wee-bit dimmer than normal. Thus, this a very shallow Partial Lunar Eclipse / Partial Eclipse of the Moon.

And, the bright object near the Moon during this Eclipse will be the ringed-planet Saturn.

A Lunar Eclipse / Eclipse of the Moon occurs when the orbit of the Moon brings our natural satellite into the Earth's shadow (shadow caused by the Earth completely blocking light from the Sun). The Earth's shadow, extending into Outer Space from the dark or night side of Earth, is divided into two sections: the dim Penumbra or Penumbral shadow, which encircles the deeper Umbra or Umbral shadow. The Moon's orbit is slightly tilted, so most months at the primary Moon phase of Full Moon, the Moon moves above or below the Earth's shadow, with no Eclipse occurring.

A Lunar Eclipse / Eclipse of the Moon always occurs near the time, and including the time, of a Full Moon. Many Native Americans called the Full Moon of November the Corn Moon or Barley Moon in addition to being known to European and American farmers as the Harvest Moon, but, more on that later.

When the Earth's dim shadow, known as the Penumbra, falls on the Moon, it is called a Penumbral Lunar Eclipse / Penumbral Eclipse of the Moon. Because the Earth's shadow is dim in this case, this type of Eclipse is difficult to discern.

When the Earth's deep shadow, known as the Umbra, falls on only part of the Moon's surface, this is known as a Partial Lunar Eclipse / Partial Eclipse of the Moon. This is more easily visible, if you are in the right location and weather conditions are acceptable.

A Total Lunar Eclipse / Total Eclipse of the Moon is when the Earth's deep shadow, or Umbra, completely envelops the Moon. Usually, a Total Lunar Eclipse / Total Eclipse of the Moon only occurs once every 2.5 years, approximately, as seen from someplace in the world. The last one was seen in North America on 2022 May 15 / 16.

Of course, "Totality" / Total Phase of a Total Lunar Eclipse / Total Eclipse of the Moon is the most impressive part of this type of Eclipse, what most people wait to see. The Partial Phases of the Eclipse are when a piece of the Moon seems missing, as the Moon moves further into the Earth's main shadow known as the Umbra, or as the Eclipse is ending and the Moon is further moving out of the Earth's Umbra.

The Penumbral Phases of the Eclipse are difficult to see, as the Moon moves into or out of the Earth's secondary shadow or Penumbra. In this case, one would not see any chunks or bites taken out of the Moon's disk, as one would see when the Moon moves into the Umbra shadow during the Partial Phases. Instead, if your eyes are very good, you may notice a slight dimming of the light coming from the Moon, as the Moon moves further into the Penumbral shadow

Although no direct sunlight reaches the Moon during a Total Lunar Eclipse / Total Eclipse of the Moon, the Earth's atmosphere refracts the sunlight around our planet allowing a portion of the sunlight to continue to be transmitted to the Moon. However, the refracted light reaching the Moon is primarily in the yellow, orange, and red portions of the electromagnetic spectrum (the Earth's atmosphere filters-out the violet, blue, and green colors), as with orange or red-tinted sunrises and sunsets (during such a Total Lunar Eclipse / Total Eclipse of the Moon, a person standing on the side of the Moon facing Earth could see all Earth sunrises and sunsets simultaneously, as they viewed the Earth in a Total Solar Eclipse / Total Eclipse of the Sun --- but, even on the Moon, a person would need to take strong precautions to ensure their eye-sight is not damaged by such a view). Hence, it is orange or red light that is reflected from the Moon back into your eyes during a Total Lunar Eclipse / Total Eclipse of the Moon.

Hence, particularly during the middle of a Total Lunar Eclipse / Total Eclipse of the Moon, the Moon will not disappear from view but can be seen with an orange or reddish tint, what some call "blood red" (this is sometimes referred to as a “Blood Moon”). If the Earth had no atmosphere, likely no sunlight would reach the Moon during a Total Lunar Eclipse / Total Eclipse of the Moon, and there would be no "Blood Moon;" the Moon would seem to completely disappear.

Harvest Moon

More evening light, coming just after the earlier sunsets of late Summer and early Autumn, occur with the Harvest Moon (the Full Moon of September) and a few days near the day of this Full Moon (weather-permitting). Traditionally, this time of year helped give farmers more light in the evening as they work to harvest their crops before the coming Winter. However, anyone can take advantage of this extra evening light, as the early Autumn evenings continue with moderate temperatures.

For this year, the Harvest Moon will be the Full Moon of Tuesday Evening, 2024 September 17, at 10:34 p.m. Eastern Daylight Saving Time (EDT) / September 18, 2:34 Coordinated Universal Time (UTC). Of course, the Harvest Moon becomes visible (weather-permitting) in the vicinity of the time of sunset on the days around the day of Full Moon.

For farmers eager to finish harvesting their crops, the bright Full Moon which shines on their farms for the several evenings closest to the Autumnal Equinox is called the Harvest Moon. This year the Autumnal Equinox, the beginning of the season of Autumn or Fall in the Earth's Northern Hemisphere and the beginning of the season of Spring in the Southern Hemisphere, will occur on Sunday Morning, 2024 September 23 at 8:44 a.m. EDT / 12:44 UTC.

The Harvest Moon is one of the signature astronomical events shortly before the beginning of, or shortly after the beginning of, the Fall season. It is an event particularly anticipated by farmers of both the past and the present. As many crops reach the time of harvest in late Summer and early Autumn, often the work of the harvest has to continue past sunset, which comes earlier and earlier each evening.

Nature has come to the rescue of these farmers, with a bright Full Moon (weather-permitting), which arrives just around the time of sunset, that allows farmers and their staff to continue the harvest after the Sun's direct light has dissipated. Hence, long-ago this Full Moon came to be known as the Harvest Moon.

For a similar reason, the Full Moon of October is often known as the Hunter's Moon, which allowed Native Americans to continue the hunt after sunset, to begin to store meat for the coming Winter months. However, the Harvest Moon is designated as the closest Full Moon to the Autumnal Equinox, and such a Full Moon does not always occur in September. Every few years the Harvest Moon occurs in October, shortly after the Autumnal Equinox. During those years, the Hunter's Moon occurs in November.

This year, the Hunter's Moon occurs on Thursday Morning, 2024 October 17 at 7:26 a.m. EDT / 11:26 UTC. Of course, the Hunter's Moon becomes visible (weather-permitting) in the vicinity of the time of sunset on the days around the day of Full Moon. This year's Hunter's Moon will be another so-called “Super-Moon” (the third of four so-called “Super-Moons” in 2024), being the largest Full Moon of 2024.

On average, the Moon rises about 50 minutes later each day. However, during the days near the Autumnal Equinox, the Moon rises each day only about 25-to-35 minutes later each day in the U.S.A., and only 10-to-20 minutes later each day in much of Canada and Europe. Thus, for several days around the time of the Autumnal Equinox, the Harvest Moon appears to rise around the same time each evening (roughly coinciding with local sunset), providing light at the time most needed by farmers.

The reason for this is due to the Ecliptic, the apparent path of the Sun, Moon, and planets through Earth's sky, which makes a narrow angle with the horizon this time of year. It is this narrow angle which provides that moonrise occurs around the time of sunset, near the time of the Full Moon of September (for the Harvest Moon) and near the time of the Full Moon of October (for the Hunter's Moon). Hence, several evenings (before darkness has fallen) appear to have a rising Full Moon.

Also, at this time of year when farmers need moonlight the most, the Harvest Moon appears larger and more prominent, due to the mysterious but well-known "Moon Illusion" that makes the Moon seem larger when it is near the horizon. And, while near the horizon, the Moon is often reddened by clouds and dust, creating the appearance of a large, rising red ball.

Some even liken a rising Harvest Moon to a rising "Great Pumpkin," of Peanuts comic-strip fame! In the Peanuts' network-television cartoon just before Halloween each year (originally aired on CBS-TV on 1966 October 27) titled, "It's the Great Pumpkin, Charlie Brown", the “Great Pumpkin” rises over the pumpkin patch to provide gifts to all good little boys and girls.

Although Western Cultures consider September the beginning of Autumn (meteorologists and climatologists consider September 1 the beginning of Meteorological Autumn), the ancients often termed this as "Mid-Autumn". By this reckoning, Autumn actually began at the traditional Cross-Quarter Day of August 1 (when harvesting of wheat usually begins) and ends at the traditional Cross-Quarter Day of All-Hallow's Eve, also known as Halloween.

This year's Harvest Moon will also be a so-called "Super-Moon", the second of four in 2024. A so-called "Super-Moon" occurs when the Full Moon is closer to the Earth than average, and hence, the Moon appears a little larger than average in the sky.

The orbit of the Moon around the Earth is not a perfect circle, but an ellipse. Hence, during the near-monthly orbit of the Moon around the Earth, at one time during the month the Moon is closer to the Earth than normal (known as Lunar Perigee) and about a half-month later the Moon is farther from the Earth than normal (known as Lunar Apogee). Hence, when the Primary Moon Phase of Full Moon occurs at or near Lunar Perigee, some people refer to the slightly larger visible Full Moon as a so-called "Super-Moon".

This month's Lunar Perigee occurs about 10 hours after the Harvest Moon - Wednesday Morning, 2024 September18 at 9:00 a.m. EDT / 13:00 UTC: 222,007.228 statute miles / 357,286 kilometers distance of the Moon from Earth.

Native Americans also called the Full Moon of September the Corn Moon or Barley Moon, as Corn and Barley were among their main crops. Sometimes, the September Full Moon in the Northern Hemisphere is also known as the Fruit Moon. Other Full Moon names for September include Chrysanthemum Moon (China), Singing Moon (Celtic), Nut Moon (American Indian - Cherokee), Mulberry Moon (American Indian - Choctaw), and Moon When the Calves Grow Hair (American Indian - Dakotah Sioux).

In the Southern Hemisphere, where Winter is turning to Spring, the September Full Moon is known as the Lenten Moon, Worm Moon, Crow Moon, Sugar Moon, Chaste Moon, or Sap Moon. Another Full Moon name for September includes Storm Moon (South Africa).

The Harvest Moon in the Southern Hemisphere occurs in March or April, with the same advantages to Southern Hemisphere farmers as the Harvest Moon in the Northern Hemisphere.

Live-stream Web-cast of this Partial Lunar Eclipse / Partial Eclipse of the Moon can be found at the following Internet link --

Link >>> https://www.timeanddate.com/live/eclipse-lunar-2024-september-18

Internet Links to Additional Information ---

Moon: Link >>> https://en.wikipedia.org/wiki/Moon

Lunar Eclipse / Eclipse of the Moon: Link >>> https://en.wikipedia.org/wiki/Lunar_eclipse

Harvest Moon: Link >>> https://en.wikipedia.org/wiki/Full_moon#Harvest_moon

Why Autumn Leaves Change Color: Link >>> http://spacewatchtower.blogspot.com/2013/10/colorful-fall-foliage-astronomy-affects.html

Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss

"Partial Eclipse of Harvest Moon Tue. Night"

Friday, 2024 September 13.

Artificial Intelligence not used in the writing or production of this article.

* Other Walsh-Authored Blog & Web-Sites: Link >>> https://buhlplanetarium.tripod.com/gawweb.html

Monday, August 26, 2024

Odd 'Wow!' Radio Signal from Outer Space Explained ?

The wow! scribble on the computer printout

Image of the 1977 computer print-out where the 'Wow' Signal was discovered.

(Image Source: Smithsonian Magazine)

By Glenn A. Walsh

Reporting for SpaceWatchtower

Scientists have now reported a possible explanation for an odd radio signal received from Outer Space in 1977. Originally described as the 'Wow!' Signal, some considered the possibility of a radio signal broadcast from an extraterrestrial civilization. Now, a more natural explanation has been proposed.

A strong narrow-band radio signal was detected on 1977 August 15 by the Big Ear Radio Telescope on the grounds of Perkins Observatory at Ohio Wesleyan University in Delaware, Ohio. Operated by the Ohio State University from 1963 to 1998, this radio telescope was part of the university's Search for Extraterrestrial Intelligence (SETI) project.

It was astronomer Jerry Ehman who discovered, what he referred to as the 'Wow!' Signal, on a computer print-out from automated observations the previous night. This intense and narrow transmission from Outer Space had lasted at least 72 seconds. On the print-out Mr. Ehman circled in bright red ink the series of letters and numbers that represented the unusual radio transmission. Then, he wrote next to the circled letters and numbers, in the margin: Wow!

In 1994, Mr. Ehman told newspaper reporter Barry Kawa, of the Cleveland Plain Dealer, “Without thinking, I wrote ‘Wow!' It was the most significant thing we had seen.”

Scientists considered this signal so unusual, because it was so intense and had a highly specific frequency. As this signal was similar to a natural radio transmission by hydrogen (Chemical symbol: H) atoms, this suggested that it was not a normal transmission from Outer Space. Of course, some people assumed that this may be a broadcast from an alien civilization. Actually, seeking such alien transmissions was one of the primary purposes of this Big Ear Radio Telescope.

However, on August 16 three scientists proposed an alternate explanation for the 'Wow!' Signal, published in a pre-print Internet web-site for academic papers which have not yet gone through the peer-review process: arXiv. These scientists propose that the 'Wow!' Signal may have been the result of a very rare event in Outer Space: the sudden brightening of a cold hydrogen cloud. As explained in Smithsonian Magazine: the scientists “suggest a strong source of energy, such as a flare from a super-magnetized, extremely dense star called a magnetar, could have struck a cloud of hydrogen gas and caused it to glow brighter. The cloud could have emitted a laser-like beam of radiation in a phenomenon called a maser.”

Past hypotheses held that the 'Wow!' Signal came from a passing comet or a star. These, somewhat controversial, explanations were soon dismissed by most scientists.

The lead author of this new research is Abel Mendez, a planetary astrobiologist and Director of the Planetary Habitability Laboratory. His co-authors are Kevin Ortiz Ceballos of the Harvard and Smithsonian Center for Astrophysics and Jorge Zuluaga of the University of Antioquia in Colombia.

They analyzed archived data that had been collected using the huge Arecibo Observatory Radio Telescope in Puerto Rico. In 2020, this famous telescope was decommissioned and dismantled by the U.S. National Science Foundation, after the radio dish was damaged by two cable breaks which threatened the structural integrity of the support structure for the suspended platform.

This proposed explanation is not supported by all scientists. This is particularly true since the proposed explanation has never been observed in the Universe. So, the alien communication hypothesis has still not been completely dismissed.

Actually, the Search of Extraterrestrial Intelligence by radio began exactly 100 years ago, last week. It was on 1924 August 21 that, under the urging of retired Massachusetts' Amherst College Astronomy Professor David Todd, U.S. Army and Navy radio stations, as well as the general public, started listening for radio messages from the planet Mars. Several years earlier, radio pioneers Nicola Tesla and Guglielmo Marconi had reported receiving odd radio signals from Outer Space, which they thought could have come from Mars.

A century ago this-past week, Mars and Earth were closer than the two planets had been in many years. The Amherst astronomer thought this might be a time that Martians would try to contact Earth via radio.

By 1924, most scientists believed that Mars was too cold and dry to have human-like life, but not everyone else agreed. Businessman, author, and mathematician Percival Lowell, who had constructed an astronomical observatory in Flagstaff, Arizona specifically to study Mars, had publicly promoted the idea that Martians had built canals to bring water from the poles to the rest of a dying planet. Hence, the general public was enthralled with the idea of intelligent life on Mars.

One hundred years ago, Dr. Todd had asked radio stations to go silent for five minutes each hour for several nights, to make it easier to hear the radio signals from Mars; only radio station WRC in Washington DC actually did so. However, other military, commercial, and amateur radio operators still listened for the extraterrestrial signals. And, a leading military cryptographer was made available to decode any messages from Mars.

There were a lot of radio signals received during this first SETI radio search, but the signals came from Earth or natural radio sources in the Universe. No message from Mars was ever detected.

Internet Links to Additional Information ----

'Wow!, Signal: Link >>> https://en.wikipedia.org/wiki/Wow!_signal

Ohio State University Radio Observatory (former home of Big Ear Radio Telescope):

Link >>> https://en.wikipedia.org/wiki/Ohio_State_University_Radio_Observatory

Arecibo Radio Telescope: Link >>> https://en.wikipedia.org/wiki/Arecibo_Telescope

Related Blog-Post ---

"50th Anniversary: Kecksburg, Pa. "UFO" Incident." Wed., 2015 Dec. 9.

Link >>> http://spacewatchtower.blogspot.com/2015/12/50th-anniversary-kecksburg-pa-ufo.html

Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss

"Odd 'Wow!' Radio Signal from Outer Space Explained ?"

Monday, 2024 August 26.

Artificial Intelligence not used in the writing or production of this article.

* Other Walsh-Authored Blog & Web-Sites: Link >>> https://buhlplanetarium.tripod.com/gawweb.html

SpaceWatchtower

Sunday, April 6, 2025

60 Years Ago: Arthur C. Clarke's Vision of Geostationary Satellites Comes True

Monday, January 27, 2025

Coordinated Lunar Time Zone for the Moon

Friday, September 20, 2024

Fall Begins at Equinox Sunday Morning

"Partial Eclipse of Harvest Moon Tue. Night". Fri., 2024 Sept. 13.

Link >>> https://spacewatchtower.blogspot.com/2024/09/partial-eclipse-of-harvest-moon.html

Friday, September 13, 2024

Partial Eclipse of Harvest Moon Tue. Night

Monday, August 26, 2024

Odd 'Wow!' Radio Signal from Outer Space Explained ?

"50th Anniversary: Kecksburg, Pa. "UFO" Incident." Wed., 2015 Dec. 9.

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