APOD: The Prague Astronomical Clock (2017 Nov 07)

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APOD: The Prague Astronomical Clock (2017 Nov 07)

Postby APOD Robot » Tue Nov 07, 2017 5:07 am

Image The Prague Astronomical Clock

Explanation: In the center of Prague there's a clock the size of a building. During the day, crowds gather to watch the show when it chimes in a new hour. The Prague Astronomical Clock's face is impressively complex, giving not only the expected time with respect to the Sun (solar time), but the time relative to the stars (sidereal time), the times of sunrise and sunset, the time at the equator, the phase of the Moon, and much more. The clock began operation in 1410, and even though much of its inner workings have been modernized several times, original parts remain. Below the clock is a nearly-equal sized, but static, solar calendar. Pictured, the Prague Astronomical Clock was photographed alone during an early morning in 2009 March. The Prague Astronomical Clock and the Old Town Tower behind it are currently being renovated once again, with the clock expected to be restarted in 2018 June.

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Re: APOD: The Prague Astronomical Clock (2017 Nov 07)

Postby Boomer12k » Tue Nov 07, 2017 5:21 am

"It's about time, Its about space... about 2 men in the strangest place"...

Does anyone remember the TV show that is from? I thought I was the only one, but it seems I am not... I don't know if that is good or bad...

Wonderful clock...
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Re: APOD: The Prague Astronomical Clock (2017 Nov 07)

Postby Ann » Tue Nov 07, 2017 6:29 am

The clock inside the Cathedral of Lund.
Photo: David Castor.

There is something very similar in the Cathedral of Lund, Sweden.

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Re: APOD: The Prague Astronomical Clock (2017 Nov 07)

Postby neufer » Tue Nov 07, 2017 11:36 am

Click to play embedded YouTube video.
Art Neuendorffer

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Re: APOD: The Prague Astronomical Clock (2017 Nov 07)

Postby jisles » Tue Nov 07, 2017 1:07 pm

The caption says the clock shows the time at the equator. Obviously this is no different than the time at Prague's latitude. I checked the official website at https://www.pragueastronomicalclock.info/ but it doesn't mention the equator, except as one of the circles depicted on the face of the upper dial, which resembles the mater of an astrolabe.

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Re: APOD: The Prague Astronomical Clock (2017 Nov 07)

Postby neufer » Tue Nov 07, 2017 2:11 pm

jisles wrote:
The caption says the clock shows the time at the equator. Obviously this is no different than the time at Prague's latitude. I checked the official website at https://www.pragueastronomicalclock.info/ but it doesn't mention the equator, except as one of the circles depicted on the face of the upper dial, which resembles the mater of an astrolabe.

Perhaps it should have stated: the times of sunrise and sunset at the equator.
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Re: APOD: The Prague Astronomical Clock (2017 Nov 07)

Postby rstevenson » Tue Nov 07, 2017 2:14 pm

Boomer12k wrote:"It's about time, Its about space... about 2 men in the strangest place"...

Does anyone remember the TV show that is from? ...

Alas, I remember it too. It was a truly dreadful comedy about a couple of time travelling asternuts. Somehow it lasted for 26 episodes in ~1967.

Rob

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Re: APOD: The Prague Astronomical Clock (2017 Nov 07)

Postby JamieK » Tue Nov 07, 2017 2:52 pm

Image]

Saw one of these in ST. Mary's Cathedral in Gdansk, Poland many years ago. Very impressive mechanism, and pretty to look at!

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Re: APOD: The Prague Astronomical Clock (2017 Nov 07)

Postby ta152h0 » Tue Nov 07, 2017 4:25 pm

boy, that Hubble is really good
Wolf Kotenberg

dribble

Re: APOD: The Prague Astronomical Clock (2017 Nov 07)

Postby dribble » Tue Nov 07, 2017 5:19 pm

rstevenson wrote:
Boomer12k wrote:"It's about time, Its about space... about 2 men in the strangest place"...

Does anyone remember the TV show that is from? ...

Alas, I remember it too. It was a truly dreadful comedy about a couple of time travelling asternuts. Somehow it lasted for 26 episodes in ~1967.

Rob


"It's About Time" [urlhttp://www.tvobscurities.com/articles/itsabouttime/][/url]

Catalina

Re: APOD: The Prague Astronomical Clock (2017 Nov 07)

Postby Catalina » Tue Nov 07, 2017 7:33 pm

Yes, I do remember snippets of the IT'S ABOUT TIME TV show! That really jogged my memory. Lately I have been enjoying watching the non-cable, over-the-air TV stations that play older TV shows from way back. There is one station in particular that plays "all Star Trek" in the evenings, from the original Star Trek to Star Trek Voyager consecutively for several hours. I find it interesting to observe the high tech and knowledge of the universe at the time of the 60's Star Trek and compare it to the modern versions of the show and what our more advanced technology and actual understandings are today. However, I am very impressed with the beauty and technical aspects of the astronomical clocks which were engineered, developed, and built without the aid of modern-day computers.

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Re: APOD: The Prague Astronomical Clock (2017 Nov 07)

Postby RJN » Tue Nov 07, 2017 7:40 pm

Thanks to feedback both here on the Asterisk and over email, two corrections have been made to the NASA APOD text. First, it is made clear that the times of sunrise and sunset at several latitudes can be read from the clock, and that the solar calendar actually does rotate -- in fact once a year. I apologize for the oversights. - RJN

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Re: APOD: The Prague Astronomical Clock (2017 Nov 07)

Postby bls0326 » Tue Nov 07, 2017 9:28 pm

The "began operation in 1410" link goes to an interesting timeline summary of this clock. There is mention of an error made in the history of this clock in 1490. The error was discovered in the 17th century. That discovery was then lost until 1962. Almost 500 years to get an error set right.

RJN- a couple of errors found and corrected in a much more timely manner.


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