What Are the Individual Libration Percentages of the Moon?

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Discussion Overview

The discussion centers on the individual percentages of the far side of the Moon that can be observed due to various types of libration: longitude, latitude, diurnal, and physical libration. Participants are exploring the specific contributions of each type to the overall visibility of the Moon's far side.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant notes that libration allows visibility of about 9% of the far side of the Moon and seeks to understand the individual contributions of different types of libration.
  • Another participant cites NASA figures for geometrical librations as 6.5°, 7.7°, and 1°, with a physical libration of 1.5°.
  • A participant interprets these figures to suggest that longitude contributes 4%, latitude contributes 3.4%, diurnal contributes 0.5%, and physical contributes 0.8% to the visibility of the far side.
  • A participant references a post discussing diurnal libration and claims it allows for an additional 2% visibility of the Moon, prompting a question about the source of this figure.

Areas of Agreement / Disagreement

There is no consensus on the individual percentages of visibility attributed to each type of libration, and participants express uncertainty regarding the accuracy of the figures provided.

Contextual Notes

Participants express concerns about the comparability of the degrees mentioned and the assumptions underlying the calculations of visibility percentages.

Who May Find This Useful

Individuals interested in lunar observation, astrophysics, or the mechanics of celestial bodies may find this discussion relevant.

Timoothy
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I understand that Libration allows us to see a total of about 9% of the far side of the moon, but what are the individual percentages of the far side of the moon that longitude, latitude, Diurnal and physical Libration allows us to see?

I can't seem to "Google-up" these individual percentages, but surly this is known information, and it seems odd to me that it's not readily available.
 
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Hi Timoothy! :smile:

NASA gives figures of 6.5° 7.7° and 1° for the "geometrical" librations and 1.5° for "physical" libration are given at http://www-istp.gsfc.nasa.gov/stargaze/Smoon4.htm" :wink:

(btw. i found this by googling "Patrick Moore" :biggrin:)
 
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tiny-tim said:
Hi Timoothy! :smile:

NASA gives figures of 6.5° 7.7° and 1° for the "geometrical" librations and 1.5° for "physical" libration are given at

http://www-istp.gsfc.nasa.gov/stargaze/Smoon4.htm"

Hi tt, thanks for your reply.

I had read that page before but moved on since I wasn't sure if they were comparing apples to apples with the "degrees" they were talking about, but assuming the degrees they give ( 7.7, 6.5, 1 and 1.5) are the totals that the different types of Libration allows us to see of the far side of the moon, then Longitude is 4%, Latitude is 3.4%, Diurnal is .5% and Physical is .8%.
 
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https://www.physicsforums.com/showpost.php?p=145092&postcount=14

"Diuranl Libration is due the fact that over the course of time from moonrise to moonset we see the Moon from different angles as the Earth rotates. Thus allows us to see about 2% more of the Moon."


Hi Janus
How did you come up with the figure of 2% for Diurnal Libration?
 

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