APOD: Great Refractor and Lunar Eclipse (2021 Nov 26)

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APOD: Great Refractor and Lunar Eclipse (2021 Nov 26)

Post by APOD Robot » Fri Nov 26, 2021 5:05 am

Image Great Refractor and Lunar Eclipse

Explanation: Rain clouds passed and the dome of the Lick Observatory's 36 inch Great Refractor opened on November 19. The historic telescope was pointed toward a partially eclipsed Moon. Illuminated by dim red lighting to preserve an astronomer's night vision, telescope controls, coordinate dials, and the refractor's 57 foot long barrel were captured in this high dynamic range image. Visible beyond the foreshortened barrel and dome slit, growing brighter after its almost total eclipse phase, the lunar disk created a colorful halo through lingering clouds. From the open dome, the view of the clearing sky above includes the Pleiades star cluster about 5 degrees from Moon and Earth's shadow.

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Re: APOD: Great Refractor and Lunar Eclipse (2021 Nov 26)

Post by orin stepanek » Fri Nov 26, 2021 12:49 pm

LH7528_36EclipsePartialWithPlieades_1024x1024.jpg
The Pleiades was a neat companion to the eclipsed moon! :D
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Re: APOD: Great Refractor and Lunar Eclipse (2021 Nov 26)

Post by JohnD » Fri Nov 26, 2021 1:30 pm

I've always wondered how an astronomer can look through such a giant telescope, when their size means that the pivot (excuse my ignorant use of a simplistic term!) and so the eyepiece, must be so far from the ground. I had visions of a chair on the end of an articulated arm! But a recent "Sky at Night" (the longest running TV programme in history, presented, monthly, by Patrick Moore for 56 years until his deat, and still running) showed the observatory at Hurstmonceaux, the successor to the Greenwich Observatory. The 26" Thompson Refractor telescope is still there, in an observatory, with a rising floor! Like a lift, the whole floor goes up or down to allow the astronomer to stand, or sit at their instrument. Wow!

See (if you can) https://www.bbc.co.uk/iplayer/episode/m ... rough-time about ten minutes in.

I know that no modern astronomer peers through the telescope, they see what a camera at the eyepiece shows, but what a magnificent piece of engineering!

John

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Re: APOD: Great Refractor and Lunar Eclipse (2021 Nov 26)

Post by Chris Peterson » Fri Nov 26, 2021 2:04 pm

JohnD wrote:
Fri Nov 26, 2021 1:30 pm
I've always wondered how an astronomer can look through such a giant telescope, when their size means that the pivot (excuse my ignorant use of a simplistic term!) and so the eyepiece, must be so far from the ground. I had visions of a chair on the end of an articulated arm! But a recent "Sky at Night" (the longest running TV programme in history, presented, monthly, by Patrick Moore for 56 years until his deat, and still running) showed the observatory at Hurstmonceaux, the successor to the Greenwich Observatory. The 26" Thompson Refractor telescope is still there, in an observatory, with a rising floor! Like a lift, the whole floor goes up or down to allow the astronomer to stand, or sit at their instrument. Wow!

See (if you can) https://www.bbc.co.uk/iplayer/episode/m ... rough-time about ten minutes in.

I know that no modern astronomer peers through the telescope, they see what a camera at the eyepiece shows, but what a magnificent piece of engineering!

John
Several historical observatories have elevating floors. And there are an assortment of seating platforms that have been designed, as well. I've sat in the observing cage of the Hale scope at Palomar and looked through an eyepiece. Since then, scopes are so large that you just ride along with them. (Even though these scopes aren't used with eyepieces, some do have the ability to allow for that, either for testing purposes or just for fun.)
Chris

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Re: APOD: Great Refractor and Lunar Eclipse (2021 Nov 26)

Post by neufer » Fri Nov 26, 2021 2:13 pm

https://en.wikipedia.org/wiki/Lick_Observatory wrote:
Click to play embedded YouTube video.

<<The first telescope installed at the Lick Observatory was a 12-inch refractor made by Alvan Clark. Astronomer E. E. Barnard used the telescope to make "exquisite photographs of comets and nebulae", according to D. J. Warner of Warner & Swasey Company.

In 1886, Lick Observatory begins supplying Railroad Standard Time to the Southern Pacific Railroad, and to other businesses, over telegraph lines. The signal was generated by a clock manufactured by E. Howard & Co. specifically for the Observatory, and which included an electric apparatus for transmitting the time signal over telegraph lines. While most of the nation's railroads received their time signal from the U.S. Naval Observatory time signal via Western Union's telegraph lines, the Lick Observatory Time-Signal was used by railroads from the West coast all the way to Colorado.

The 36-inch refracting telescope on Mt. Hamilton was Earth's largest refracting telescope during the period from when it saw first light on January 3, 1888, until the construction of Yerkes Observatory in 1897. E. E. Barnard used the telescope in 1892 to discover a fifth moon of Jupiter, Amalthea. This was the first addition to Jupiter's known moons since Galileo observed the planet through his parchment tube and spectacle lens. In 1905 (Jan. 5 and Feb. 27), Charles Dillon Perrine discovered the sixth and seventh moons of Jupiter (Elara and Himalia) on photographs taken with the 36-inch Crossley reflecting telescope which he had recently rebuilt.[

In 1928, Donald C. Shane studied Carbon stars, and was able to distinguish them into spectral classes R0–R9 and N0–N7 (on this scale N7 is the reddest and R0 the bluest). This was an expansion of Annie Jump Cannon of Harvard's work on Carbon stars that had divided them into R and N types. The N stars have more cyanogen and the R stars have more carbon.>>
http://www.star.ucl.ac.uk/~pac/obafgkmrns.html wrote:
Mnemonics for the Harvard Spectral Classification Scheme
by Jesse S. Allen

<<The modern stellar spectral classification scheme (also known as the Harvard Spectral Classification Scheme) was created by Annie Jump Cannon through her examination of spectra from 1918 to 1924. Originally, the scheme used capital letters running alphabetically, but was later reordered to reflect the surface temperatures of stars. In order of decreasing temperature, these types were O, B, A, F, G, K. and M. Three additional categories also in the scheme: R, N, and S types, were later realized to represent stars with peculiar heavy-metal abundances. [An S-type star is a cool giant with approximately equal quantities of carbon & oxygen in its atmosphere. The class was originally defined in 1922 by Paul Merrill for stars with unusual absorption lines and molecular bands now known to be due to s-process elements. The bands of zirconium monoxide (ZrO) are a defining feature of the S stars.] Other types (Q for novae, W for Wolf-Rayet stars, etc) are not encountered frequently. According to astronomical myth, Henry Norris Russell suggested the following mnemonic to assist students in remembering the scheme:
  • Oh Be A Fine Girl, Kiss Me!
There have been many efforts since to improve on this mnemonic. The motivations are various: to include the R, N, and S, to find a mnemonic for the vast number of astronomers who would really not want to be kissed by a girl or just as a fun homework assignment for students. Owen Gingerich (CfA) holds an annual contest in his "The Astronomical Perspective" course , and a summary of many winning submissions was published in his article "The Great Mnemonics Contest" in Phyllis Lugger, ed, ASTEROIDS TO QUASARS: A SYMPOSIUM HONOURING WILLIAM LILLER (Cambridge University Press, 1991). The Committee on the Status of Women in Astronomy also held a competition on the subject in 1995 and Russell's mnemonic remained the most popular of the submissions. Our humble efforts, which draw on all these resources, plus many suggestions from others, are presented here:
  • Oh Be A Fine [Guy/Gal/Girl] Kiss Me (Right Now [Smack]).
    Out Beyond Andromeda, Fiery Gases Kindle Many Radiant New Stars.
    Obese Balding Astronomer Found Guilty Killing Many Reluctant Nonscience Students.
    Oh Backward Astronomer, Forget Geocentricity; Kepler's Motions Reveal Nature's Simplicity.
    Orbs, Bright And Fair, Generate Kinder Memories: Revolving Nighttime Skies.
    Only Bright Astral Fires Going Kaput Make Real Neutron Stars.
    Oh Brutal And Ferocious Gorilla, Kidnap My Roommate Next Saturday.
    Overseas Bulletin: A Flash! Godzilla Kills Mothra! (Rodan Named Successor).
    Oven-Baked Ants, when Fried Gently, and Kept Moist, Retain Natural Succulence.
    When Obstreperous Beasts Approach, Fragrant Geraniums Knowingly May Receive Night's Stigmata.
    Old Bottles And Filthy Garbage Kill Many Rare Natural Species.
    Oregon Beavers Attack Famous Gardens, Killing Many, Rangers Now Shooting.>>
Art Neuendorffer

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Re: APOD: Great Refractor and Lunar Eclipse (2021 Nov 26)

Post by neufer » Fri Nov 26, 2021 2:27 pm

Chris Peterson wrote:
Fri Nov 26, 2021 2:04 pm

I've sat in the observing cage of the Hale scope at Palomar and looked through an eyepiece.
How did you rate that privilege :?:

(Did you actually observe anything through the eyepiece?)
(Did they let you spin around like we used to do on soda fountain counter stools?)
Chris Peterson wrote:
Fri Nov 26, 2021 2:04 pm

Several historical observatories have elevating floors. And there are an assortment of seating platforms that have been designed, as well.
It has that added advantage of placing one a little closer to the planets/stars one is observing :idea:
Art Neuendorffer

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Chris Peterson
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Re: APOD: Great Refractor and Lunar Eclipse (2021 Nov 26)

Post by Chris Peterson » Fri Nov 26, 2021 2:42 pm

neufer wrote:
Fri Nov 26, 2021 2:27 pm
Chris Peterson wrote:
Fri Nov 26, 2021 2:04 pm

I've sat in the observing cage of the Hale scope at Palomar and looked through an eyepiece.
How did you rate that privilege :?:

(Did you actually observe anything through the eyepiece?)
(Did they let you spin around like we used to do on soda fountain counter stools?)
The perks of being an astronomy major at Caltech, which operated the scope. Looked at Saturn and at the core of Andromeda.
Chris Peterson wrote:
Fri Nov 26, 2021 2:04 pm
Several historical observatories have elevating floors. And there are an assortment of seating platforms that have been designed, as well.
It has that added advantage of placing one a little closer to the planets/stars one is observing :idea:
There's a tangent function to consider here...
Chris

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Re: APOD: Great Refractor and Lunar Eclipse (2021 Nov 26)

Post by neufer » Sat Nov 27, 2021 1:52 am

JohnD wrote:
Fri Nov 26, 2021 1:30 pm

I've always wondered how an astronomer can look through such a giant telescope, when their size means that the pivot (excuse my ignorant use of a simplistic term!) and so the eyepiece, must be so far from the ground. I had visions of a chair on the end of an articulated arm! But a recent "Sky at Night" (the longest running TV programme in history, presented, monthly, by Patrick Moore for 56 years until his deat, and still running) showed the observatory at Hurstmonceaux, the successor to the Greenwich Observatory. The 26" Thompson Refractor telescope is still there, in an observatory, with a rising floor! Like a lift, the whole floor goes up or down to allow the astronomer to stand, or sit at their instrument. Wow!

See (if you can) https://www.bbc.co.uk/iplayer/episode/m ... rough-time about ten minutes in.

I know that no modern astronomer peers through the telescope, they see what a camera at the eyepiece shows, but what a magnificent piece of engineering!
https://en.wikipedia.org/wiki/Galileo_Galilei wrote: <<Based only on uncertain descriptions of the first practical telescope which Hans Lippershey tried to patent in the Netherlands in 1608, Galileo, in the following year, made a telescope with about 3x magnification. He later made improved versions with up to about 30x magnification. With a Galilean telescope, the observer could see magnified, upright images on the Earth. He could also use it to observe the sky; for a time he was one of those who could construct telescopes good enough for that purpose. On 25 August 1609, he demonstrated one of his early telescopes, with a magnification of about 8 or 9, to Venetian lawmakers. His telescopes were also a profitable sideline for Galileo, who sold them to merchants who found them useful both at sea and as items of trade.

On 30 November 1609, Galileo aimed his telescope at the Moon. While not being the first person to observe the Moon through a telescope (English mathematician Thomas Harriot had done it four months before but only saw a "strange spottednesse"), Galileo was the first to deduce the cause of the uneven waning as light occlusion from lunar mountains and craters. In his study, he also made topographical charts, estimating the heights of the mountains. The Moon was not what was long thought to have been a translucent and perfect sphere, as Aristotle claimed, and hardly the first "planet", an "eternal pearl to magnificently ascend into the heavenly empyrian", as put forth by Dante.>>
Art Neuendorffer