APOD: Analemma of the Moon (2020 May 07)

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APOD: Analemma of the Moon (2020 May 07)

Post by APOD Robot » Thu May 07, 2020 4:06 am

Image Analemma of the Moon

Explanation: An analemma is that figure-8 curve you get when you mark the position of the Sun at the same time each day for one year. But the trick to imaging an analemma of the Moon is to wait bit longer. On average the Moon returns to the same position in the sky about 50 minutes and 29 seconds later each day. So photograph the Moon 50 minutes 29 seconds later on successive days. Over one lunation or lunar month it will trace out an analemma-like curve as the Moon's actual position wanders due to its tilted and elliptical orbit. To create this composite image of a lunar analemma, astronomer Gyorgy Soponyai chose a lunar month from March 26 to April 18 with a good stretch of weather and a site close to home near Mogyorod, Hungary. Crescent lunar phases too thin and faint to capture around the New Moon are missing though. Facing southwest, the lights of Budapest are in the distance of the base image taken on March 27. <br><br>

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orin stepanek
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Re: APOD: Analemma of the Moon (2020 May 07)

Post by orin stepanek » Thu May 07, 2020 1:06 pm

APOD_Soponyai_Analemma_Moon.jpg
Does make an interesting photo! Yesterday at 5AM was a nice view of an almost full moon I was fortunate enough to see as I don''t usually pay much attention to the lunar phases! :D
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Re: APOD: Analemma of the Moon (2020 May 07)

Post by meniero » Thu May 07, 2020 1:25 pm

I think of the curve of the lunar revolution photographed is wrongly called "lunar analemma": this is a dialectical forcing because only the "eight" curve that makes the Sun can be called "analemma" for its etymological definition. The analemma (from the Greek ανάλημμα) indicates the pedestal of the solar sundial and therefore can not be referred to the Moon. In my opinion this lunar curve should be called a "synodic curve”.

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Chris Peterson
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Re: APOD: Analemma of the Moon (2020 May 07)

Post by Chris Peterson » Thu May 07, 2020 1:52 pm

meniero wrote:
Thu May 07, 2020 1:25 pm
I think of the curve of the lunar revolution photographed is wrongly called "lunar analemma": this is a dialectical forcing because only the "eight" curve that makes the Sun can be called "analemma" for its etymological definition. The analemma (from the Greek ανάλημμα) indicates the pedestal of the solar sundial and therefore can not be referred to the Moon. In my opinion this lunar curve should be called a "synodic curve”.
See Etymological Fallacy.
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LarryfromJP

Re: APOD: Analemma of the Moon (2020 May 07)

Post by LarryfromJP » Thu May 07, 2020 3:25 pm

One of my favorite images of the year. Beautifully composed, thought provoking and beautiful.

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Re: APOD: Analemma of the Moon (2020 May 07)

Post by neufer » Thu May 07, 2020 4:48 pm

Chris Peterson wrote:
Thu May 07, 2020 1:52 pm
meniero wrote:
Thu May 07, 2020 1:25 pm

I think of the curve of the lunar revolution photographed is wrongly called "lunar analemma": this is a dialectical forcing because only the "eight" curve that makes the Sun can be called "analemma" for its etymological definition. The analemma (from the Greek ανάλημμα) indicates the pedestal of the solar sundial and therefore can not be referred to the Moon. In my opinion this lunar curve should be called a "synodic curve”.
See Etymological Fallacy.
https://www.etymonline.com/search?q=analemma wrote:
analemma (n.) 1650s, "projection of the celestial sphere onto the plane of the meridian," later the name of an astronomical instrument to do this (1660s), from Latin analemma name of a type of sundial known in antiquity, originally meaning "pedestal of a sundial," hence by extension the sundial itself. This is from Greek analemma "prop, support" of any kind, such as a sling for a broken arm, from analambanein "to take up; restore, repair," from ana "up" (see ana-) + lambanein "to take" (see lemma). As the name of a tabulated scale in the form of a figure 8, showing the sun's position and equation of time throughout the year, from 1832.
Art Neuendorffer

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Re: APOD: Analemma of the Moon (2020 May 07)

Post by ptahhotep » Thu May 07, 2020 6:16 pm

The 'bit longer' reads as though it is suggesting that a month is longer than a year. It actually means wait a bit more than a day between pictures. Also the Moon doesn't return to the same point in the sky, if it did there would be no analemma, just a spot. It is more correct to say that it is the time when the Earth's rotation has caught up with the Moon's orbit.

gioyhofer@libero.it

Re: APOD: Analemma of the Moon (2020 May 07)

Post by gioyhofer@libero.it » Thu May 07, 2020 8:43 pm

I have realised a similar picture 2 years ago, but with a shorter interval, 24 hours and 41 minutes. The curve widens and reproduces the orbit of the Moon combined with the movement of the Earth in space in 28 days.

Here's the picture

www.giorgiahoferphotography.com

gioyhofer@libero.it

Re: APOD: Analemma of the Moon (2020 May 07)

Post by gioyhofer@libero.it » Thu May 07, 2020 8:49 pm

https://www.giorgiahoferphotography.com/?lightbox=dataItem-k8tre1pj

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Re: APOD: Analemma of the Moon (2020 May 07)

Post by BillBixby » Thu May 07, 2020 9:21 pm

gioyhofer@libero.it wrote:
Thu May 07, 2020 8:49 pm
https://www.giorgiahoferphotography.com ... m-k8tre1pj
I really like that.