The surface of Io READ THE COMMENTS (Jordi_Delpeix_Borrell)

Contains: Solar system body or event

The surface of Io READ THE COMMENTS

In the image above, Europa is on the left of the planet and Io and its shadow, transiting over Jupiter.

Io’s most prominent feature is a yellow-white equatorial band, that is covered with highly reflective sulphur-dioxide frost. With a visual albedo of 0,6, this bright terrain contrasts starkly with the satellite’s reddish-brown polar regions, which have a visual albedo of only 0,3.

These polar markings were sources of confusion to astronomers. When observed against a dark sky, Io’s dusky polar caps, tend to blend into the background, distorting the moon’s outline. In 1797, this deceptive appearance, led William Herschel, the greatest observer of his era, to suggest that Io might not be spherical. A century later, Harvard astronomer Pickering, mistook Io’s bright equatorial band for the satellite itself and concluded that Io was an egg shaped body.

In 1891, Barnard dispelled this notion, observing with the 91 cm Lick refractor, Barnard saw Io as distinctly round, crowned by dark polar caps separated by a bright band running roughly parallel to Jupiter’s equator.

Nowadays, it’s great to notice that this striking appearance can be captured by amateurs from their backyard. I’m really happy to register real surface details in a disc of only 1,1” diameter.

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	Distinct awarded users	Total awarded images
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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
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	Image of the day	Top pick	Top pick nominations	Total submitted
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Mix of multiple sources
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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.

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The surface of Io READ THE COMMENTS

The surface of Io READ THE COMMENTS

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The surface of Io READ THE COMMENTS

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