Wednesday, November 17, 2021

Early Fri. Lunar Eclipse Longest in 1,000 Years

   Latter phases of the Partial Lunar Eclipse / Partial Eclipse of the Moon seen from Gloucestershire, United Kingdom on 2019 July 17. A Partial Lunar Eclipse / Partial Eclipse of the Moon will be visible, weather-permitting, early on Friday Morning, 2021 November 19. November 19 also happens to be the 80th anniversary of the Astronomical Observatory of the original Buhl Planetarium and Institute of Popular Science (a.k.a. Buhl Science Center - Pittsburgh's science and technology museum from 1939 to 1991).

(Image Sources: Wikipedia.org, By Caroline Grubb from United Kingdom - This file was derived from: Lunar eclipse 2019-07-17 (48303346356).jpg, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=80506672) 

By Glenn A. Walsh

Reporting for SpaceWatchtower

The longest Lunar Eclipse / Eclipse of the Moon in 1,000 years can be seen early Friday morning, weather-permitting. Although this will technically be a Partial Lunar Eclipse / Partial Eclipse of the Moon, it is nearly a Total eclipse.

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.

Live-stream Web-casts 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 links to these Live-streams near the end of this blog-post).

Partial Lunar Eclipse / Partial Eclipse of the Moon

The last time a Partial Lunar Eclipse / Partial Eclipse of the Moon was longer than Friday's eclipse was on 1440 February 18. The next such long, Partial Lunar Eclipse / Partial Eclipse of the Moon will be on 2669 February 8. For a Partial Lunar Eclipse / Partial Eclipse of the Moon, this is one of the longest such eclipses at a duration of about 6 hours and 2 minutes (including the Penumbral phases of the eclipse). When considering only the Umbral phase of the eclipse, the November 19 eclipse is the longest Partial Lunar Eclipse / Partial Eclipse of the Moon this century.

The reason the duration of this eclipse is so long is because the eclipse occurs only 41 hours before the Moon reaches the monthly, apogee point in the lunar orbit,(farthest point away from the Earth for the month). The Moon takes longer to traverse the Earth's shadow during this eclipse, due to the fact that the Moon always moves more slowly when it is farther from the Earth.

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. For the November 19 eclipse, only people in eastern Europe, western Russia, much of southwestern Asia, most of Africa, and much of the Indian Ocean could not view any part of the eclipse in the sky; they would need to watch the eclipse on the Internet.


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

Early Friday Morning, 2021 November 19 -

[Eastern Standard Time (EST) / 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 --- 1:02:09 a.m. EST / 6:02:09 UTC

Partial Lunar Eclipse Begins --- 2:18:42 a.m. EST / 7:18:42 UTC

Primary Moon Phase: Full Moon – Beaver Moon --- 3:57 a.m. EST / 8:57 UTC

Greatest Partial Lunar Eclipse --- 4:02:53.1 a.m. EST / 9:02:53.1 UTC

Partial Lunar Eclipse Ends --- 5:47:04 a.m. EST / 10:47:04 UTC

Penumbral Lunar Eclipse Ends  --- 7:03:40 a.m. EST / 12:03:40 UTC


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. At the time of Greatest Partial Lunar Eclipse / Partial Eclipse of the Moon on November 19, the Moon will be 99 per-cent obscured by the Earth's Umbral shadow. The remaining 1 per-cent of the Moon's surface will be well within the Penumbral shadow of the Earth, making this a very deep Partial Lunar Eclipse / Partial Eclipse of the Moon.

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 Beaver 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 happened on 2021 May 26. The next one will be seen in North America in about half-a-year from now 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 portion 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.

Although the November 19 eclipse is a Partial Lunar Eclipse / Partial Eclipse of the Moon, at a maximum 99 per-cent obscuration during the time of greatest eclipse, the November 19 eclipse may show many of the characteristics of a Total Lunar Eclipse / Total Eclipse of the Moon. This includes the Blood Moon effect.

Aristotle Discovers World is Round Due, in Part, to Lunar Eclipse

Civilized society has known that the Earth is not flat, but is round, for about 2500 years. The famous Greek philosopher and academic, Aristotle who lived between 384 and 322 B.C., used a Lunar Eclipse / Eclipse of the Moon as one demonstration that the Earth is round. This was documented in a book he published around 350 B.C. As he observed the Earth's shadow pass across the face of the Moon, he noticed that the shadow is curved, which is one of three indications he found that the Earth is round. One of the other two indications were the concept that gravity required a common center for a planetary body such as Earth. He also noticed that different stars were seen from different locations on our planet, and some stars cannot be seen from certain locations.

Leonid Meteor Shower

The Leonid Meteor Shower (which peaked Wednesday, 2021 November 17 at 1:00 p.m. EST / 18:00 UTC) may still be slightly visible during this eclipse. Although Lunar Eclipses / Eclipses of the Moon are not usually the best time to see meteors (as a bright Moon often drowns-out the dimmer meteors), some meteors may still be visible, particularly during the time of greatest eclipse.

Full Moon of November

The Full Moon of November, in the Northern Hemisphere, is generally known as the Beaver Moon. This was the time when Native Americans set-out beaver traps, before creeks and swamps froze-over, to ensure a good supply of warm furs and pelts for the coming Winter. Although beavers do not hibernate, by the following month the beavers would be in their lodges for the Winter, difficult for hunters to trap.

This beaver fur was its most usable at this time of year, both waterproof and warm. The furs also provided a special oil, used as a hair protector. The beaver was revered by the Americans Indians, spiritually.

The Beaver Moon occurs this year on November 19 at 3:57 a.m. EST / 8:57 UTC.

While most people consider the Full Moon as the Beaver Moon, the Native Americans actually considered the whole Moon cycle (all four Moon phases) as the Beaver Moon (i.e. the Beaver Month for the 28.5-day lunar cycle). Other researchers believe the Beaver Moon name came from the fact that beavers, themselves, are active building water dams, preparing for Winter.

This month's Full Moon sometimes is also referred to as the Frost or Frosty Moon. And, some Indian tribes referred to the November Full Moon as the Deer-Mating Moon or the Fur-Pelts Moon.

For years when the Harvest Moon occurs in October (when the October Full Moon date is closer to the Autumnal Equinox than the September Full Moon date, which occurs about one-third of the time), the November Full Moon is then also known as the Hunter's Moon. However, this was not the case in 2021

In the Southern Hemisphere, the Full Moon of November is known as the Corn Moon, Milk Moon, Flower Moon, and Hare Moon.

80th Anniversary of Historic Astronomical Observatory

This November 19 also marks the 80th anniversary of the Astronomical Observatory at the original Buhl Planetarium and Institute of Popular (a.k.a. Buhl Science Center), Pittsburgh's science and technology museum from 1939 to 1991. The Observatory's primary instrument was a rather unique 10-inch Siderostat-type Refractor Telescope.

A now-renowned astronomer, who was then Director of the Harvard College Observatory, Harlow Shapley, delivered the keynote address dedicating the Observatory on Wednesday Evening, 1941 November 19. First Light through the telescope, that evening, was the ringed-planet Saturn.

A siderostat-type telescope is unique such that the telescope itself does not move, save for the movements of the Earth. A flat, first-surface mirror, which does move, reflects celestial images into the telescope. Thus, the public could look through the telescope while standing in a heated observing room, while the telescope remains in the outside elements.

The siderostat-type telescope was developed by French inventor Jean Leon Foucault, who also developed the Foucault Pendulum as a classic demonstration that the Earth rotates on its axis. Only two siderostat-type telescopes, larger than the Buhl Planetarium telescope, were ever constructed.

The first was the Great Paris Exhibition Telescope of 1900, and with a 49-inch objective lens was also the largest refracting telescope ever built. A 15-inch Siderostat-type Refracting Telescope was built around 1929 by a private astronomy enthusiast, which eventually became one of the main instruments of the Flower and Cook Observatory in suburban Philadelphia, owned by the University of Pennsylvania.

Both the Paris and Philadelphia telescopes have been dismantled. The Paris telescope is not recoverable, without the construction of an entirely new telescope tube and observatory. The future is unclear for the Philadelphia telescope, which is now in the possession of amateur astronomers in Jacksonville.

Regrettably, Buhl Planetarium's historic 10-inch Siderostat-type Refractor Telescope, which is legally owned by the City of Pittsburgh, is also currently dismantled and in storage. The author (Glenn A. Walsh) served as Astronomical Observatory Coordinator for the original Buhl Planetarium Observatory from 1986 to 1991.

http://buhlplanetarium2.tripod.com/observatory/pix/Siderostat_A.jpgThe 10-inch Siderostat-type Refractor Telescope in the Astronomical Observatory of the original Buhl Planetarium and Institute of Popular Science (a.k.a. Buhl Science Center), Pittsburgh's science and technology museum from 1939 to 1991.

(Image Sources: Francis G. Graham, Professor Emeritus of Physics, Kent State University and Friends of the Zeiss)

Live-stream Web-casts of 2021 November 19 Partial Lunar Eclipse / Partial Eclipse of the Moon:

Link 1 (TimeandDate.com) >>> https://www.timeanddate.com/live/eclipse-lunar-2021-november-19

Link 2 (Griffith Observatory, Los Angeles) >>> https://griffithobservatory.org/event/lunar-eclipse-online-broadcast-nov-18-2021/

Link 3 (Lowell Observatory, Flagstaff) >>> https://lowell.edu/event/partial-lunar-eclipse-nov-19/

Link 4 (Virtual Telescope Project) >>> https://www.virtualtelescope.eu/2021/11/05/the-19-nov-2021-partial-lunar-eclipse-online-event/ 

Link 5 (Astronomical Society of South Australia) >>> https://www.assa.org.au/events/online-star-parties/lunar-eclipse-live-stream-19-november-2021/

Internet Links to Additional Information ---

More Information - 2021 November 19 Eclipse: Link >>> https://buhlplanetarium4.tripod.com/astrocalendar/2021.html#eclipselun20211119 

Leonid Meteor Shower: Link >>> https://earthsky.org/astronomy-essentials/everything-you-need-to-know-leonid-meteor-shower/

Historic Astronomical Observatory of the original Buhl Planetarium and Institute of Popular Science (a.k.a. Buhl Science Center), Pittsburgh's science and technology museum from 1939 to 1991:

Link >>> http://spacewatchtower.blogspot.com/2016/11/75th-anniversary-americas-5th-public.html

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

                 Saturday, 2021 November 13.

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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

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