Thursday, January 27, 2022

LaserSETI Expands Search for Alien Life

LaserSETI

  (Image Source: SETI Institute)

By Glenn A. Walsh

Reporting for SpaceWatchtower

LaserSETI - no, it is not the name of a new laser-light show at your local planetarium!

Last week, the SETI Institute announced a major expansion in their search for extraterrestrial life. LaserSETI will now use special facilities to search for possible laser beams originating from extraterrestrial civilizations.

SETI is best known for using radio telescopes to search for signals from alien civilizations. Using traditional telescopes to search planets in our Solar System, as well as exo-planets in other star systems, for possible life, has also been a strong research thrust of many astronomers, as well as SETI and NASA.

For the last 62 years, SETI, the Search for Extraterrestrial Intelligence, has primarily been scanning the sky for radio signals from other civilizations. With rare exceptions, there have been no evidence of radio communication or signals coming from other civilizations.

The strongest candidate for a possible radio signal from another civilization came on 1977 August 15, when the Ohio State University's Big Ear radio telescope received the fabled “WOW Signal.” Astronomer Jerry R. Ehman, a few days later, discovered the anomaly of a 72-second narrow-band radio signal in data he was reviewing. He was so impressed by the magnitude of the signal that he wrote “WOW” next to the signal on the computer print-out. Although many have tried to replicate this discovery, no one has been able to find the “WOW Signal” again.

While radio signals have been the primary form of wireless communication on Earth for the last century (101 years ago, radio station KDKA-AM in Pittsburgh became the world's first commercial, broadcast station), optical communication with lasers has become more practical and efficient for scientific purposes, including for computer communication.

It is now thought that advanced civilizations may also find optical communications as more practical and efficient. Hence, SETI is now expanding the search for alien communication into the optical spectrum.

As of last month, SETI has installed a new laser instrument, described as an expensive combination lens-camera-computer at the Haleakala Observatory, 10,000 feet above mean sea-level on a mountain on Maui, Hawaii. This instrument faces eastward.

Facing westward is an identical facility located at the Robert Ferguson Observatory in Sonoma, California. With both facilities, they can now scan a 150-degree arc of the sky, each night, at more than 1,000 times per second. The computer system filters the light, looking for laser-type signatures.

Eliot Gillum, principal investigator for LaserSETI, said it’s “a big step forward in searching for technosignatures,” and that it’s the “first project in either optical or radio astronomy designed to cover the entire sky.”

However, these two facilities are just the beginning. The long-range plan is to install a few more similar instruments on the other side of the world, to increase coverage of the night-time sky. The long-term goal is to scan the entire sky with several systems, radio, laser, and traditional telescopes, in all directions, 24-hours a day, 365 days a year.

It is very fortunate that laser detectors are relatively inexpensive. For many years now, SETI has had to do with only private donations, as government funding for SETI dried-up quite a while ago.

The Hawaii instrument only cost $100,831, which was raised from 531 people on a crowd-funding Internet web-site: Indiegogo. With the assistance of a small team, Eliot Gillum installed the facility himself, to save money.

Another approach to SETI could be to use infrared telescopes, similar to the the James Webb Space Telescope (JWST) that NASA launched last month. However, these are much more expensive; the JWST cost $10 billion! So, for now, SETI will have to let NASA handle infrared research.

Internet Links to Additional Information ---

SETI:

Link 1 >>> https://www.seti.org/ 

Link 2 >>> https://en.wikipedia.org/wiki/Search_for_extraterrestrial_intelligence 

"WOW Signal": Link >>> https://en.wikipedia.org/wiki/Wow!_signal 

Related Blog Posts ---

"Finally! Live-Stream: Christmas Launch of Next Great Space Telescope." (James Webb Space Telescope) Fri., 2021 Dec. 24.

Link >>> http://spacewatchtower.blogspot.com/2021/12/finally-live-stream-christmas-launch-of.html

 

"143 UFO Sightings, By U.S. Navy Pilots, Remain Unidentified." Mon., 2021 June 28.

Link >>> http://spacewatchtower.blogspot.com/2021/06/143-ufo-sightings-by-us-navy-pilots.html

 

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

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

 

"Tue. Morning Fireball Over Pittsburgh Seen in Several States." Thur., 2015 Feb. 19.

Link >>> http://spacewatchtower.blogspot.com/2015/02/tue-morning-fireball-over-pittsburgh.html

 

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

                 Thursday, 2022 January 27.

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gaw

Glenn A. Walsh, Informal Science Educator & Communicator:
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), Pittsburgh's science & technology museum from 1939 to 1991.
Formerly Trustee, Andrew Carnegie Free Library and Music Hall, Pittsburgh suburb of Carnegie, Pennsylvania.
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

 

Wednesday, January 12, 2022

Rare Supernova Seen by Astronomers

Scientists see a red giant star go supernova for the first time.

 Supernova SN 2020tlf observed by the Keck Observatory in Hawaii. (Image Source: Keck Observatory)

By Glenn A. Walsh

Reporting for SpaceWatchtower

A rare Supernova, registered as SN 2020tlf, has been observed by astronomers. A Supernova is a powerful and luminous stellar explosion, when the original star either collapses into a neutron star or black hole, or is completely destroyed.

The progenitor star was a Red Super-giant, the largest type of star in the Universe in volume (but not, necessarily, the brightest or most massive of stars); such stars are hundreds or even more than a thousand times the radius of Earth's Sun. And, this is the first time scientists have been able to observe a Supernova event before, during, and after the event! The Supernova observations were reported in a new study in the January 6 issue of the Astrophysical Journal.

"This is a breakthrough in our understanding of what massive stars do moments before they die," said lead author Wynn Jacobson-Galán of the University of California Berkeley. "Direct detection of pre-Supernova activity in a red supergiant star has never been observed before in an ordinary Type II Supernova. For the first time, we watched a red supergiant star explode!" (quote from a public statement reported on https://keckobservatory.org/dying-star)

In the Summer of 2020, they detected the Red Super-giant star that was about to Supernova, using the University of Hawaii Institute of Astronomy Pan-STARRS 1 telescope in Maui, Hawaii, due to the large amount of light the star was emitting. In the Autumn of 2020, scientists captured the Supernova explosion using the Low Resolution Imaging Spectrometer (LRIS) of the W.M. Keck Observatory on Mauna Kea, Hawaii, including the Supernova's first spectrum.

While most Red Super-giant stars seem to be calm before a Supernova event, the new observations indicate that this star ejected a massive amount of stellar materials before the actual explosion. So, now scientists believe that some Red Super-giants may significantly change their internal structure before an explosion.

"We've never confirmed such violent activity in a dying red supergiant star where we see it produce such a luminous emission, then collapse and combust, until now," study co-author Raffaella Margutti, an astrophysicist at the University of California Berkeley, said in the Keck Observatory statement.

Supernova SN 2020tlf is not in the Milky Way Galaxy. It is located 120 million light-years away from Earth in Galaxy NGC 5731; one light-year is the distance light travels in one year of time: 5,878,625,370,000 statute miles / 9.5 trillion kilometers. The original star was about 10 times more massive than Earth's Sun. SN 2020tlf was observed in the constellation Bootes the Herdsman.

A Supernova occurs when a very massive star (weighing 8 to 15 times the weight of Earth's Sun) runs out of hydrogen and helium fuel (and, in the case of Red Giants, also iron and nickel) by nuclear fusion and then collapses of their own weight, which results in a huge carbon-fusion explosion. Larger stars would collapse into a Black Hole. A smaller star, such as our Sun, would become a White-dwarf.

With the data gathered from the explosion of SN 2020tlf, astronomers will more easily be able to search for similar Red Super-giant stars about to explode.

Although such observations are rare through human history, several Supernovae have been observed. One of the most famous was in A.D. 1054, recorded by Chinese, Japanese, and Islamic astronomical observers; due to the Supernova's brightness, Chinese observers called it a “Guest Star”. Today, the Crab Nebula (with its Pulsar / Neutron Star), located in the constellation Taurus the Bull (6,500 light-years from Earth), marks the spot where this Supernova occurred. What is known as SN 1054 had an estimated brightness, what astronomers refer to as Apparent Visual Magnitude, of -6, brighter than any other star in the night-time sky.

The most recent, nearby Supernova, observed in, what is known as, the Local Group of Galaxies, occurred on 1987 February 23 at 2:35:35 Eastern Standard Time (EST) / 7:35:35 Coordinated Universal Time (UTC). Supernova SN 1987A occurred in the Large Magellanic Cloud, a galaxy which orbits the Milky Way Galaxy. This Supernova was observed in the constellation Dorado the Dolphin-fish, 160,000 light-years from Earth. The Apparent Visual Magnitude of SN 1987A was +2.9.

 Internet Links to Additional Information ---

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

List of Observed Supernovae: Link >>> https://en.wikipedia.org/wiki/List_of_supernovae

 Red Super-giant Star: Link >>> https://en.wikipedia.org/wiki/Red_supergiant 

Statement of Keck Observatory - Observations of Supernova SN 2020tlf:

Link >>> https://keckobservatory.org/dying-star

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

                 Wednesday, 2022 January 12.

                             Like This Post?  Please Share!

           More Astronomy & Science News - SpaceWatchtower Twitter Feed:
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                Want to receive SpaceWatchtower blog posts in your in-box ?
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gaw

Glenn A. Walsh, Informal Science Educator & Communicator:
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), Pittsburgh's science & technology museum from 1939 to 1991.
Formerly Trustee, Andrew Carnegie Free Library and Music Hall, Pittsburgh suburb of Carnegie, Pennsylvania.
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 3, 2022

Astro-Calendar: 2022 Jan. / Smallest Full Moon of 2022 Jan. 17

                  Full Moon in the darkness of the night sky. It is patterned with a mix of light-tone regions and darker, irregular blotches, and scattered with varying sizes of impact craters, circles surrounded by out-thrown rays of bright ejecta.

The smallest Full Moon of 2022 will occur on Monday, January 17 at 6:48 p.m. EST / 23:48 UTC. This Full Moon will appear a little smaller than other Full Moon phases this year, because it occurs only three days after Lunar Apogee, when the Moon is farthest from the Earth in its orbit for this month. Lunar Apogee occurs this month on Friday, January 14 at 4:00 a.m. EST / 9:00 UTC: 252,155.53667 statute miles / 405,805 kilometers.

(Image Sources: Wikipedia.org, By Gregory H. Revera, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=11901243)

Astronomical Calendar for 2022 January ---
Link >>> https://buhlplanetarium4.tripod.com/astrocalendar/2022.html#jan

 Related Blog Post ---

"Astro-Calendar: 2021 Dec. / Launch of 2 NASA Science Missions; Antarctic Solar Eclipse Dec.4." Wed., 2021 Dec. 1.

Link >>> https://spacewatchtower.blogspot.com/2021/12/astro-calendar-2021-dec-launch-of-2.html

Source: Friends of the Zeiss.
            Monday, 2022 January 3.

                             Like This Post?  Please Share!

            More Astronomy & Science News - SpaceWatchtower Twitter Feed:
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                Want to receive SpaceWatchtower blog posts in your in-box ?
                Send request to < spacewatchtower@planetarium.cc >.

gaw

Glenn A. Walsh, Informal Science Educator & Communicator:
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), Pittsburgh's science & technology museum from 1939 to 1991.
Formerly Trustee, Andrew Carnegie Free Library and Music Hall, Pittsburgh suburb of Carnegie, Pennsylvania.
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

Friday, December 24, 2021

Finally! Live-Stream: Christmas Launch of Next Great Space Telescope

Artist’s conception of NASA’s James Webb Space Telescope in orbit.

 Artist's concept of the fully-deployed James Webb Space Telescope (JWST).

(Image Source: NASA)

By Glenn A. Walsh

Reporting for SpaceWatchtower

Finally! After years of delays including launch delays this month, the next great space telescope is scheduled for launch no earlier than Christmas morning: Saturday, 2021 December 25 at 7:20 a.m. Eastern Standard Time (EST) / 12:20 Coordinated Universal Time (UTC). NASA's James Webb Space Telescope, what is described by scientists as the successor to the Hubble Space Telescope, will be launched using an Ariane 5 launch vehicle from the Guiana Space Centre, northwest of Kourou in French Guiana, on the north Atlantic Ocean coast of South America.

NASA will provide Live-Stream coverage of the launch on NASA-TV, beginning Christmas morning at 6:00 a.m. EST / 11:00 UTC. NASA-TV will carry a post-launch news conference on Christmas morning at 9:00 a.m. EST / 14:00 UTC (assuming the launch occurs as scheduled). Internet link to NASA-TV is located near the end of this blog-post.

The James Webb Space Telescope (JWST), which is much larger than the Hubble Space Telescope, is designed to seek stars and galaxies shortly after the “Big Bang”, the creation of our Universe approximately 13.8 billion years ago. The Hubble Space Telescope (HST), along with most traditional terrestrial telescopes, observe using visible light. The JWST is designed to use the infrared portion of the electromagnetic spectrum to search where visible light telescopes cannot.

JWST will be the largest space telescope ever launched. With a primary mirror size of 21.3 feet / 6.5 meters, it is much larger than the HST primary mirror: 7.8 feet / 2.4 meters.

The JWST mirror is comprised of 18 gold-plated beryllium, hexagonal segments. A 5-layer Sun-shield, the size of a tennis court, protects the mirror from any heat radiated by the Sun, Earth, or Moon. Made of silicon and aluminum-coated Kapton, this Sun-shield should keep the JWST primary mirror and related instruments at a temperature no higher than 50 degrees Kelvin / -370 degrees Fahrenheit / -223 degrees Celsius. To search for the earliest galaxies and stars in the Universe, using infrared, the telescope mirror must be extremely cold and shielded from heat.

After the launch of JWST, the telescope will travel 930,000 statute miles / 1.5 million kilometers from Earth to a point in Deep Space known as L2. L2 is the second Lagrange Point of the Earth – Sun system. A Lagrange Point is a site where the gravity between two large bodies, in this case the Earth and the Sun, is relatively balanced; satellites can stay at such a point with minimum energy usage. It is a point in Deep Space where the JWST can remain, somewhat easily, in an orbit and away from the heat of the Earth and the Sun.

Why launch from French Guiana? There are several reasons:

  • The Guiana Space Centre is operated by the European Space Agency (ESA) and the French space agency (National Centre for Space Studies: CNES); along with the Canadian Space Agency (CSA), the ESA is part of the international collaboration with NASA on this mission. The launch site and launch vehicle are ESA contributions to the mission.

  • The launch site is near the Equator, which means less energy is needed for launches, particularly to maneuver a spacecraft into equatorial, geostationary orbit. The closer to the Equator a launch occurs, the greater energy from the rotation of the Earth can be utilized in the launch; and, hence, less rocket fuel is needed. As Florida is the closest U.S. state to the Equator, this is why the Kennedy Space Center was sited in Florida.

  • French Guiana has open sea to the east. As with the Kennedy Space Center, this allows lower rocket stages and other launch debris to fall harmlessly in the Atlantic Ocean, without risking life or property.

The JWST mission has four key goals:

  • Search for light from the very first stars and galaxies that formed in our Universe, shortly after the Big Bang. The Universe is estimated to be about 13.8 billion years old; JWST is expected to find light from stars and galaxies approximately 13.5 billion years in the past (13.5 billion light-years from Earth).

  • Study the formation and evolution of galaxies.

  • Study the formation of stars and planetary systems..

  • Further study planetary systems, looking for the origins of life.

The Hubble and James Webb space telescopes are different in mission duration. The Hubble Space Telescope has had the advantage of being in a close Earth orbit, where Space Shuttle astronauts have been able to service and upgrade the telescope. With the conclusion of the Space Shuttle program, the ability to service and upgrade the HST seems to have ended. As the HST is now, it is expected to last until some tine in the 2030s.

The JWST, being placed much further away from the Earth, cannot be serviced or upgraded by current space technology. To stay at the L2 orbital site, which is a somewhat unstable orbit, rocket propellant must be used. JWST has 10 years of rocket propellant on-board, to maintain the L2 configuration of the telescope. So, 10 years is the upper limit of the mission duration.

The nominal science mission is officially 5 years, with the hope that the telescope can continue to be used for research for 10 years. Once the JWST spacecraft reaches L2, there will be a 6-month commissioning phase, before the official science mission begins. The commissioning phase includes the careful, and very risky, unfolding of the huge telescope mirror, very crucial Sun-shield, and related instruments.

The JWST is named after James Webb, the second Administrator of NASA. James Webb ran NASA from February of 1961 until October of 1968, for seven years retiring just before the first manned flight of the Apollo spacecraft..He was in charge of NASA during all Mercury and Gemini flights. And, he was Administrator during the investigation of the tragic fire, which killed three astronauts, during a ground test of the Apollo 1 spacecraft on Friday, 1967 January 27.

The James Webb Space Telescope, originally designed to cost $1 billion to $3.5 billion, had many cost over-runs, throughout the many years of development and delays. With the launch of JWST, the final cost of the project will be $10 billion.

More than 30 years ago, even before the 1990 launch of the Hubble Space Telescope, planning had begun on JWST. Construction of JWST began in 2004, after having been named to honor James Webb in 2002.

In 1993, when the U.S. Congress killed the Superconducting Super Collider project for particle physics in Texas, scientists had feared the same thing would happen to JWST. But, former U.S. Senator Barbara Mikulski (D-Md.) helped to save JWST at that time.

The launch of JWST had been expected some time between 2007 and 2011. Due to continual cost over-runs, the launch kept being delayed. In 2011, the U.S. House of Representatives voted to cancel the JWST project, due to the continual cost over-runs. Scientists and space enthusiasts, including teachers and school children, successfully rallied to save the project.

As it took many years to develop and construct the JWST, planning for the next great space telescope has just begun. In November, a committee convened by the independent National Academies of Sciences, Engineering, and Medicine has recommended that another huge space telescope should be designed and built to study exo-planets (planets orbiting stars other than our Sun) and search for signs of life. It is projected that this new telescope would be launched some time in the 2040s.

NASA-TV Live-Stream Coverage of the Launch of the James Webb Space Telescope:

Link >>> https://www.nasa.gov/nasalive

Internet Links to Additional Information ---

James Webb Space Telescope (JWST) -

Link 1 >>> https://jwst.nasa.gov/

Link 2 >>> https://www.nasa.gov/mission_pages/webb/main/index.html 

Link 3 >>> https://en.wikipedia.org/wiki/James_Webb_Space_Telescope 

Ariane 5 rocket (to launch JWST): Link >>> https://en.wikipedia.org/wiki/Ariane_5 

Guiana Space Centre (launch site for JWST): Link >>> https://en.wikipedia.org/wiki/Guiana_Space_Centre 

L2 - Second Lagrange Point in Earth - Sun System: Link >>> https://en.wikipedia.org/wiki/Lagrange_point#L2

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

                 Friday, 2021 December 24.

                             Like This Post?  Please Share!

           More Astronomy & Science News - SpaceWatchtower Twitter Feed:
            Link >>> https://twitter.com/spacewatchtower

        Astronomy & Science Links: Link >>> http://buhlplanetarium.tripod.com/#sciencelinks

                Want to receive SpaceWatchtower blog posts in your in-box ?
                Send request to < spacewatchtower@planetarium.cc >.

gaw

Glenn A. Walsh, Informal Science Educator & Communicator:
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), Pittsburgh's science & technology museum from 1939 to 1991.
Formerly Trustee, Andrew Carnegie Free Library and Music Hall, Pittsburgh suburb of Carnegie, Pennsylvania.
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

Sunday, December 19, 2021

Winter Begins at Solstice Tue.; Ursid Meteors Peak Wed.

http://buhlplanetarium.tripod.com/pix/graphics/solsticeimage008.png

This diagram shows the position of the Earth, in relation to the Sun, at the time of the Winter Solstice, as well as the other solstice and equinoxes of the year, in Earth's Northern Hemisphere.
[Graphic Source: ©1999, Eric G. Canali, former Floor Operations Manager of the original Buhl Planetarium & Institute of Popular Science (a.k.a. Buhl Science Center ), Pittsburgh's science & technology museum from 1939 to 1991, and Founder of the South Hills Backyard Astronomers amateur astronomy club; permission granted for only non-profit use with credit to author.]

By Glenn A. Walsh

Reporting for SpaceWatchtower

The season of Winter, in the Northern Hemisphere of Earth, begins at the moment of the Winter / December Solstice, late Tuesday Morning, 2021 December 21 at 10:59 a.m. Eastern Standard Time (EST) / 15:59 Coordinated Universal Time (UTC). This moment also marks the astronomical beginning of the Summer season in the Southern Hemisphere.

This year's Winter Solstice marks the 53rd anniversary of the launch of Apollo 8, the first human mission to the Moon. Apollo 8 astronauts Frank Borman, James Lovell, and William Anders launched from Cape Canaveral, Florida on 1968 December 21 at 7:51 a.m. EST / 12:51 UTC, entered lunar orbit early on the morning of Christmas Eve, orbited the Moon ten times, and returned to Earth on 1968 December 27.

Almost exactly 24 hours after the Winter Solstice will mark the peak time for the annual Ursid Meteor Shower. This meteor shower peaks Wednesday Morning, 2021 December 22 at 11:00 a.m. EST / 16:00 UTC. Although, with the bright, Long-Nights Full Moon occurring just a few days (Saturday Evening, 2021 December 18 at 11:35 p.m. EST / December 19, 4:35 UTC) before the Ursids Meteor Shower peak, Ursid meteors may be more difficult to find this year.

                                                              Winter Solstice

In etymology, the word solstice comes from the Latin terms sol (Sun) and sistere (to stand-still). In ancient times, astronomers / astrologers / priests recognized that one day of the year when the Sun would appear to reach its lowest point in the sky for the entire year. The motion of the Sun's apparent path in the sky (what is known astronomically today as the Sun's declination) would cease on this day, and the Sun would appear to stand-still, before reversing direction.

With our Gregorian Calendar, this usually occurs on, or very close to, December 21. In ancient times, when people used the Julian Calendar, the Winter Solstice was on, or very close to, December 25, what we now know as Christmas Day. Mid-Winter festivals, at the time of the Winter Solstice, were common in ancient times. Instead of competing with these traditions, the early Roman Catholic Church Christianized the Winter festivals by observing the birth of Jesus Christ on December 25 (the actual birth date of Jesus was probably in late Summer or early Autumn).

Today, we know that, while the Sun does have motions, it is actually the motion of the Earth, tilted on its axis 23.44 degrees from the plane of our Solar System while revolving around the Sun, that causes the Earth's seasons. Hence, as the Earth arrives at the point in its orbit around the Sun, where the south polar axis is most directly inclined toward the Sun (thus, the Sun appears at its lowest point for the year in the Northern Hemisphere sky) around December 21, this marks the Winter Solstice in the Northern Hemisphere (and the Summer Solstice in the Southern Hemisphere).

Alternately around June 21, the Summer Solstice marks the beginning of Summer in the Northern Hemisphere (and this date also marks the Winter Solstice, which is the beginning of Winter in the Southern Hemisphere) as the Earth reaches the point in its orbit where the north polar axis is most directly inclined toward the Sun.

The day of the December Solstice is the only time of the year when the Sun reaches the point of Local Solar Noon at the South Pole. Conversely, it is also the only time of the year when Local Solar Midnight occurs at the North Pole. And, of course, it is the reverse during the June Solstice: the only time the Sun reaches the point of Local Solar Noon at the North Pole and the only time when Local Solar Midnight occurs at the South Pole.

Although the Winter months in the Northern Hemisphere are known for the year's coldest weather, the Earth is actually at the point in its orbit closest to the Sun (astronomically known as the point of Perihelion) on or very near January 2. The Earth is farthest from the Sun, each year shortly after the Northern Hemisphere's Summer Solstice, on or very near July 5 (the point of Aphelion). Over a half-year's time between Earth Perihelion and Earth Aphelion, the difference in distance between the Sun and Earth varies by about 3.2 million miles.

Solar radiation, and hence heat from the Sun, to warm an Earth hemisphere depends on the length of daylight and the angle of the Sun above the horizon. Earth receives about 7 per-cent more solar radiation from the Sun during the time of Earth Perihelion in January, than at the time of Earth Aphelion in July. However, the tilt of the planet's axis toward the Sun determines the additional and more direct solar radiation received by a planet's northern or southern hemisphere, and hence, the warmer season of the respective hemisphere.

The Earth's Perihelion in January, and Aphelion in July, are due to the elliptical nature of the Earth's orbit around the Sun. Perihelion and Aphelion would not occur if the Earth's orbit was a true circle.

Since the Earth is closest to the Sun near the beginning of the Northern Hemisphere's Winter Season, the Earth, then, moves faster in its orbit around the Sun than it moves in July, making the Northern Hemisphere's Winter a shorter season than Summer. Winter will last for only 89 days, while this past-Summer lasted nearly 93 days. This is one of the observed consequences of Johannes Kepler's Laws of Planetary Motion, which he published at the beginning of the 17th century.

The day of the Winter Solstice is known as the “shortest day of the year” and the “longest night of the year” as the Sun shines on the Northern Hemisphere for the shortest length of time for the entire year, on this day. For this reason, Homeless Persons' Memorial Day is commemorated on December 21.

Since the Summer Solstice in June, the number of daylight hours have slowly diminished each day, with the night-time hours progressively increasing each day. This has benefited astronomers (to view planets and stars), amateur / ham radio operators (to communicate with other ham operators around the world), and long-distance (DX) radio enthusiasts (to receive AM / medium-wave and short-wave radio stations from around the country or around the world), who need the lack of solar radiation to ply their respective craft. Once we reach the Winter Solstice, the number of daylight hours will, now, slowly increase each day, with the night-time hours declining each day--until, once again, this reverses on the Summer Solstice.

Interestingly, the climate of a locale in the Southern Hemisphere is, on average, slightly milder than a location at the same latitude in the Northern Hemisphere, because the Southern Hemisphere has significantly more ocean water and much less land. Water warms-up and cools-down more slowly than does land. The only exception is the Antarctic Continent, which is colder than the Northern Hemisphere's Arctic region, possibly because most of the Arctic region is covered with water (although, often frozen water on the surface, but liquid water beneath the ice) while Antarctica is mostly a land mass.

On the Winter Solstice, the Sun appears (from Earth's perspective) to be in the constellation Sagittarius—that is, if you could view the stars behind the Sun on the Winter Solstice, you would see the stars of Sagittarius. Previously, just a few days earlier, the Sun had appeared to be in the constellation Ophiuchus. The change, when the Sun appeared to move from Sagittarius to Ophiuchus, occurred on December 17.

However, a couple thousand years ago, the Sun would have appeared to be in the constellation Capricornus during the Winter Solstice. And, about 150 years from now, the Sun will appear to be in the constellation Ophiuchus during the Winter Solstice.

This apparent change is known as Precession of the Equinoxes or Axial Precession. This is a slow “wobble” of the Earth's axis, which causes the background stars or constellations that the Sun appears in to change over an approximately 25,771.5 year-cycle. This cycle runs through 12 traditional constellations of the zodiac, plus the constellation Ophiuchus, comprising the constellations along the ecliptic.

Precession also causes the North Star to change over the approximately 25,771.5 year-cycle. Today, Polaris is known as the North Star, which has been used for ages by navigators. However, at the time Egypt constructed the Great Pyramid, architects used Thuban, the North Star at that time, to align the pyramid. And, about 12,000 years from today, Vega will be the North Star.

Although for the year, December 21, for Earth's Northern Hemisphere, has the fewest number of daylight hours and the most night-time hours, it may be surprising to some that this date does not have the latest sunrise time nor the earliest sunset time for the year. This is also true for the June 21 solstice in the Southern Hemisphere.

Depending on a location's latitude, the latest sunrise time actually occurs a few days after the respective solstice, while the earliest sunset time occurs a few days before the day of the solstice. These time differences are due to, what scientists call, the Equation of Time (the Equation of Time is graphically displayed on most world globes as a figure “8”, known as the Analemma).

The U.S. Naval Observatory in Washington defines the Equation of Time: "the Equation of Time is the difference apparent solar time minus mean solar time". Apparent solar time, which is somewhat variable, directly tracks the motion of the Sun and can be measured using a sundial. Mean solar time measures solar motion if the Sun's motion was uniform; it is measured by an accurate clock which does .not vary in time measurement.

The Sun's motion does vary throughout the year. Hence, the latest sunrise time and the earliest sunset time do not occur on the actual day of the solstice.

                               Moon Before Yule or Long-Nights Moon

Late last night (Saturday Evening, 2021 December 18 at 11:35 p.m. EST / December 19, 4:35 UTC), was the Primary Moon Phase of Full Moon for the month of December. Each year, the December Full Moon is known as the Long-Nights Moon due to the great length of time the Full Moon is visible in the sky this time of year, compared to the much shorter time the Sun is in the sky at this time of year.

Many years, the December Full Moon is also known as the Moon Before Yule, when the Full Moon occurs before Christmas Day. Originally, Yule referred to the Winter Solstice, celebrated by Germanic peoples. Again, Yule was another mid-Winter festival which was eventually Christianized, so that today people refer to Yule as Christmas.

Of course, it can easily be understood why the Full Moon may be longer in the sky than the Sun this time of year, since the Winter Solstice marks the day with the shortest amount of daylight and longest duration of night. This means that early this week there will be about 14 and one-half hours of moon-light, with only about 9 and one-half hours of sunlight, weather-permitting.

In addition, this time of year the Moon climbs to its highest altitude in the sky for the year, what scientists call a high declination, while the Sun has the lowest declination for the year. The Sun, Moon, and planets all travel along and near a line known as the ecliptic. Near and during the season of Winter, the ecliptic arcs low across the sky in the daytime, because the Earth's North Pole is pointed away from the Sun this time of year. Alternately, the Full Moon on the other side of our planet benefits from the ecliptic arcing high across the sky during the night-time hours this time of year.

The December Full Moon is also very prominent, particularly when this high, bright Moon shines on a snowy-white field, which may justify the name Big Moon.

The December Full Moon was also known to Native Americans as the Cold Moon. Other names given to the December Full Moon have been reported by the Farmers' Almanac (Oak Moon) and The American Boy's Book of Signs, Signals and Symbols published in 1918 for use by the Boy Scouts (Wolves Moon and Big Moon).

Of course Cold Moon refers to the cold temperatures that begin with the start of the Winter season this month. And, the Moon Before Yule was used by the Christian settlers to refer to the Full Moon before Christmas Day (Yule being an early religious festival observed by Germanic peoples, later absorbed and equated with Christmas); of course, this name would not be used during years when the December Full Moon is after Christmas Day. With the longest night of the year occurring near the Winter Solstice, this justifies the term Long-Nights Moon, as the Full Moon is visible all-night long.

In the Southern Hemisphere, the December Full Moon is known as the Strawberry Moon, Honey Moon, and Rose Moon.

                                               Ursid Meteor Shower

Almost 24 hours after the Winter Solstice comes the peak of the annual Ursid Meteor Shower, which actually begins on December 17 and usually lasts about a week ending December 24, 25, or 26. The Ursids seem to comprise a narrow stream of debris originating from Comet Tuttle. Hence, it is difficult to see Ursid meteors outside of a 12-hour window before and after the peak, where possibly 12 meteors per-hour could be seen, under ideal conditions.

The Ursid Meteor Shower is so-named because most meteors appear to radiate from a point near the Star Beta Ursae Minoris (apparent meteor shower radiant) in the Constellation Ursa Minor (better known as the asterism the “Little Dipper”), which is the brightest star in the bowl of the Little Dipper. Some people call these meteors “Ursids,” in an attempt to emphasize that their apparent radiant is Ursa Minor, not Ursa Major (the asterism the “Big Dipper”).

However, you should not, necessarily, be looking only at the Little Dipper when looking for meteors in this shower. Meteors can appear in any part of the sky at any time (although a meteor's tail may tend to point back toward the radiant).

Of course meteor showers, like all celestial observations, are weather-permitting. If there are more than a few clouds in the sky, meteors will be much more difficult to find. Clear skies are not always available in the skies of late Autumn and early Winter. And, it is always best to get away from city lights, for the opportunity to see the smaller, dimmer meteors. A bright Moon in the sky will also make it more difficult to view the smaller, dimmer meteors. As always, the best time to view any meteor shower is between local midnight and local dawn, when the Earth is actually rotating into the stream of meteoric debris.

Binoculars and telescopes are not very useful for finding meteors. Meteors streak across the sky in a very short period of time, far too short to aim binoculars or a telescope. So, the best way to view a meteor shower is to lie on a blanket or beach towel on the ground, or use a reclining a chair, outdoors in an area with a good view of the entire sky (with few obstructions such as buildings, trees, or hills), and keep scanning the entire sky.

So, if you go out to see the Ursid Meteor Shower, start looking for meteors around local midnight, or perhaps a little later. Make sure you have a good site where you can see most of the sky, and that sky is relatively clear. Be sure to dress properly for the early morning temperatures, now that we are at the very beginning of Winter.

And, you want to go out ahead of time, before you actually start looking for meteors, to get your eyes accustomed to the dark sky. Dark-adapting your eyes for meteor-watching could take up to a half-hour.

Internet Links to Additional Information ---  

Winter Solstice:
Link 1 >>> http://scienceworld.wolfram.com/astronomy/WinterSolstice.html
Link 2 >>> http://en.wikipedia.org/wiki/Winter
Solstice: Link >>> http://en.wikipedia.org/wiki/Solstice

Popular Winter Planetarium Sky Shows Shown at Pittsburgh's original Buhl Planetarium and Institute of Popular Science (1939 to 1991), including full scripts of each show:
The Star of Bethlehem >>> http://buhlplanetarium3.tripod.com/skyshow/bethlehem/
The Stars of Winter >>> http://buhlplanetarium3.tripod.com/skyshow/winter/

 Calendar Formats ---
       Gregorian Calendar: Link >>> http://en.wikipedia.org/wiki/Gregorian_calendar
       Julian Calendar: Link >>> http://en.wikipedia.org/wiki/Julian_calendar

Primary Moon Phase of Full Moon: Link >>> http://en.wikipedia.org/wiki/Full_moon

Full Moon names ---
Link 1 >>> http://earthsky.org/astronomy-essentials/full-moon-names
Link 2 >>> https://en.wikipedia.org/wiki/Full_moon#Full_moon_names                                                      Link 3 >>> http://www.farmersalmanac.com/full-moon-names/

Ursid Meteor Shower: Link >>> http://en.wikipedia.org/wiki/UrsidsA

 Homeless Persons' Memorial Day:
Link >>> http://nationalhomeless.org/about-us/projects/memorial-day/

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

                 Sunday, 2021 December 19.

                             Like This Post?  Please Share!

           More Astronomy & Science News - SpaceWatchtower Twitter Feed:
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gaw

Glenn A. Walsh, Informal Science Educator & Communicator:
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), Pittsburgh's science & technology museum from 1939 to 1991.
Formerly Trustee, Andrew Carnegie Free Library and Music Hall, Pittsburgh suburb of Carnegie, Pennsylvania.
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

Tuesday, December 7, 2021

LIVE-STREAM NASA Launch Early Tue: Laser Communications Relay Demonstration Mission

This is the Optical Module of the Laser Communications Relay Demonstration satellite scheduled for launch on December 7.

(image sources: NASA, Wikipedia.org, By NASA - http://esc.gsfc.nasa.gov/267/278/291/Images/LLCD-Images.html (image link), Public Domain, https://commons.wikimedia.org/w/index.php?curid=30231720)

By Glenn A. Walsh

Reporting for SpaceWatchtower

UPDATE - 2021 Dec. 7:  NASA's Laser Communications Relay Demonstration Mission (LCRD) launch now targeted for Tuesday Morning, 2021 December 7, with a launch window of 4:04 to 6:04 a.m. Eastern Standard Time (EST) / 9:04 to 11:04 Coordinated Universal Time (UTC).

NASA-TV Live-stream coverage of launch begins December 7 at 3:30 a.m.  EST / 8:30 UTC. Internet link to NASA-TV Live-stream coverage near end of this blog-post.

Previously scheduled launch dates had been Summer of 2021, November 22, December 4, December 5, and December 6. Recent delays in the launch of the LCRD have been due to the detection of a leak in a rocket propellant ground storage system. Weather prospects for a December 7 launch are 80 per-cent positive.

The launch of the LCRD mission is just one of several experimental satellites to be launched on the United Launch Alliance Atlas V rocket on the STP-3 mission from Complex 41 at Cape Canaveral Space Force Station on the east coast of Florida. The STP-3 mission will launch several classified Department of Defense satellites, in addition to the NASA LCRD mission, at a cost of $1.14 billion.

With the LCRD launch, NASA is testing the next step in optical communications. Using infrared lasers, this test will demonstrate the technology to transfer science data between Earth and space satellites and vehicles.

For more information on the LCRD mission, see the original blog-post of November 13:

Link >>> http://spacewatchtower.blogspot.com/2021/11/nasa-launch-dec-4-laser-communications.html

NASA-TV Live-stream coverage of LCRD launch: Link >>> https://www.nasa.gov/nasalive

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

                 Tuesday, 2021 December 7.

                             Like This Post?  Please Share!

           More Astronomy & Science News - SpaceWatchtower Twitter Feed:
            Link >>> https://twitter.com/spacewatchtower

        Astronomy & Science Links: Link >>> http://buhlplanetarium.tripod.com/#sciencelinks

                Want to receive SpaceWatchtower blog posts in your in-box ?
                Send request to < spacewatchtower@planetarium.cc >.

gaw

Glenn A. Walsh, Informal Science Educator & Communicator:
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), Pittsburgh's science & technology museum from 1939 to 1991.
Formerly Trustee, Andrew Carnegie Free Library and Music Hall, Pittsburgh suburb of Carnegie, Pennsylvania.
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

Wednesday, December 1, 2021

Astro-Calendar: 2021 Dec. / Launch of 2 NASA Science Missions; Antarctic Solar Eclipse Dec.4

        SE2021Dec04T.gif

This graphic shows the coverage of a Total Solar Eclipse / Total Eclipse of the Sun on December 4 in Antarctica and small portions of southern Africa and southeastern tip of Australia. More information:

Link >>> https://buhlplanetarium4.tripod.com/astrocalendar/2021.html#eclipsesol2021124

NEVER LOOK DIRECTLY AT ANY SOLAR ECLIPSE / ECLIPSE OF THE SUN,  UNLESS YOU HAVE THE PROPER EQUIPMENT AND PROPER TRAINING TO DO SO SAFELY!

SOLAR ECLIPSE / ECLIPSE OF THE SUN: TIPS FOR SAFE VIEWING:

Link >>> https://buhlplanetarium2.tripod.com/FAQ/soleclipse/solareclipseviewingtips.html

(Graphic Sources: NASA, Wikipedia.org, By A.T. Sinclair - http://eclipse.gsfc.nasa.gov/, Public Domain, https://commons.wikimedia.org/w/index.php?curid=8976527)

Launch of NASA Laser Communications Relay Demonstration (LCRD) satellite December 5:

Link >>> https://buhlplanetarium4.tripod.com/astrocalendar/2021.html#lcrd

Launch of NASA James Webb Space Telescope (JWST) December 22:

Link >>>  https://buhlplanetarium4.tripod.com/astrocalendar/2021.html#jwst

Astronomical Calendar for 2021 December ---
Link >>> https://buhlplanetarium4.tripod.com/astrocalendar/2021.html#dec

 Related Blog Post ---

"Astro-Calendar: 2021 Nov. / Lunar Eclipse Nov. 19." Mon., 2021 Nov. 1.

Link >>> https://spacewatchtower.blogspot.com/2021/11/astro-calendar-2021-nov-lunar-eclipse.html

Source: Friends of the Zeiss.
            Wednesday, 2021 December 1.

                             Like This Post?  Please Share!

            More Astronomy & Science News - SpaceWatchtower Twitter Feed:
            Link >>> https://twitter.com/spacewatchtower

        Astronomy & Science Links: Link >>> http://buhlplanetarium.tripod.com/#sciencelinks

                Want to receive SpaceWatchtower blog posts in your in-box ?
                Send request to < spacewatchtower@planetarium.cc >.

gaw

Glenn A. Walsh, Informal Science Educator & Communicator:
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), Pittsburgh's science & technology museum from 1939 to 1991.
Formerly Trustee, Andrew Carnegie Free Library and Music Hall, Pittsburgh suburb of Carnegie, Pennsylvania.
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