Lunar libration (MAILLARD)

Contains: Solar system body or event

Lunar libration

Acquisition type: Lucky imaging

Lunar libration

Acquisition type: Lucky imaging

Here are two views of the same region of the lunar North Pole that allow us to visualize this phenomenon called lunar libration.

I deliberately aligned these two images on the same horizontal plane with the north materialized by an N, to be able to compare them more easily.

We might think that 50% of the lunar surface is available to our gaze, since it always presents us with the same face. That is not entirely accurate. The Moon is animated by slight periodic oscillations, called librations, which allow us to observe up to 59% of its surface (but of course never more than 50% simultaneously).

The case presented here is a latitude libration. It is due to the fact that the moon's rotational axis is not exactly perpendicular to the plane of its orbit. As a result, the Earth observer can successively see a thin additional net of lunar surface beyond the average limits of the North and South limbs. This libration in latitude reaches about 6°50' (on the right view it is about 5°).

There is also a longitude libration that reveals a thin additional band of lunar surface to the west or east.

All of these successively revealed areas represent 18% of the lunar surface.

You may notice the distorting effect due to perspective. A circular crater in this libration zone looks like a heavily flattened ellipse.

Finally, it should be noted that the study of libration zones depends on three simultaneous conditions: that the libration is indeed taking place, a favourable lighting angle and a calm and transparent atmosphere.

An attractive subject more for the amateur astronomer..

Please note: The following tables are updated every 24 hours.

Distribution of astrophotographers

This table shows the number of distinct astrophotographers who have been assigned and IOTD/TP award compared to the total number of images awarded.
	Distinct awarded users	Total awarded images
Image of the day
Top picks
Top pick nominations

Distribution of subject types

This table shows the distribution of awards per subject type, compared to the popularity of images of that subject type.
	Image of the day	Top pick	Top pick nominations	Total submitted
Deep sky
Solar system
Extremely wide field
Star trails
Northern lights
Noctilucent clouds
Landscape

Distribution of data sources

This table shows the distribution of awards per data source, compared to the popularity of images acquired from that data source.
	Image of the day	Top pick	Top pick nominations	Total submitted
Backyard
Traveller
Own remote observatory
Amateur hosting facility
Public amaeteur data
Professional, scientific grade data
Mix of multiple sources
Other
Unknown

The “AstroBin Image of the Day and Top Picks”, or IOTD/TP, is a long-running system to promote beautiful, interesting, peculiar, or otherwise amazing astrophotographs, with a focus on technical excellence. Learn more.

Submitted The date and time when you submitted this image for IOTD/TP consideration.	...
Views by Submitters (available since September 19th, 2023) Every image is assigned to 50% of available Submitters. In the event that at least 80% of them don't view the image before its time in the IOTD/TP process expires, it's assigned to the other 50% of Submitters and the process begins anew.
Promotions by Submitters When 3 distinct Submitters promote the image, it moves on to the next stage of the process: evaluation for Top Pick status. This requirement, in addition to anonymization of images and distribution to only a subset of them, prevents biases and ensures that the best images are selected.
Promotions by Reviewers When 3 distinct Reviewers promote the image, it moves on to the next stage of the process: evaluation for IOTD status.
Early dismissal Staff members have a lot of images to inspect on a daily basis, and they can dismiss images if they believe they don't meet the requirements for IOTD/TP selection. If an image is dismissed 5 times, it's removed from the process. This streamlines the process and ensures that any bias present in promotions could be overruled by other staff members.

Status	n/a
Started	n/a
Astrometry.net job	n/a
PixInsight job	n/a
PixInsight queue size	n/a
PixInsight stage	n/a

Image Index:

Contribution Index (beta):

Lunar libration

Lunar libration

Equipment

Acquisition details

Description

Comments

Histogram

Image Index:

Contribution Index (beta):

Lunar libration

Lunar libration

Equipment

Acquisition details

Description

Comments

Histogram

Notifications

AstroBin is in READ ONLY mode

Sorry :-(

Sorry :-(

Sorry :-(

Are you really sure?

Warning!

Warning!

Are you sure?

Report abuse

Slideshow settings

IOTD/TP stats (last [x] days)

Distribution of astrophotographers

Distribution of subject types

Distribution of data sources

Sorry

Sorry

Share

Upload new revision

Upload uncompressed source (XISF/FITS/PSD/TIFF)

Delete image and all its revisions?

Delete original image?

Delete all other versions?

Delete all revisions?

IOTD/TP stats

The following people like this image

The following people bookmarked this image

Warning

Flag malfunctioning thumbnails

Contains

Remove yourself as a collaborator

Plate-solving information