2018, January 31: Chicago’s View of the Lunar Eclipse


Lunar Eclipse (image Credit: NASA)

A lunar eclipse occurs on the morning of January 31 during the second full moon of the month and the new year.  All the events of the lunar eclipse are visible from Asia, Australia, the Pacific Ocean Basin and western North America.

In the Chicago area, the moon sets in the western sky during the maximum phase.

Here are the events of the eclipse for Chicago area observers:

January 31, 4:51 a.m. CST — The moon is low in the western sky (altitude 23 degrees), just about two hours before it sets.  At this time, the moon enters the outer section of the lunar shadow — the penumbra.  For most observers not much change occurs in the moon’s brightness.

5:28 a.m. CST (Moon’s altitude, 16 degrees) — The moon appears lower in the western sky as the earth is rotating.  Morning twilight begins at this time.

5:48 a.m. CST (Moon’s altitude, 12 degrees) — The moon’s descent toward the horizon continues.  At this time the moon begins to move into the darker umbra and the partial eclipse begins.

6:01 a.m. CST (Moon’s altitude, 10 degrees) — The partial eclipse continues and the sky brightens.  Nautical twilight occurs at this time.  The sky is bright enough to distinguish the horizon — the line the separates the sky from the ground.

6:35 a.m. CST (Moon’s altitude, 4 degrees) — The moon’s descent continues as it is now only about 30 minutes before moonset.  Sometimes the moon and sun seem orange when they rise,  This is from the atmosphere erasing the yellow and blue light from  sunlight — atmospheric extinction. (This can also diminish the brightness of celestial objects.)  The moon appears orange during a lunar eclipse when red and orange light are bent through our atmosphere  While the moon is not in total eclipse, yet, the moon appears orange from the eclipse as well as the atmospheric extinction.  At this time Civil Twilight occurs; the sky is bright.  Street lights begin turning off.  It’s easy to distinguish details in terrestrial features.

6:51 a.m. CST (Moon’s altitude, 2 degrees) — The moon is very low in the western sky.  The moon is now completely inside the earth’s shadow — total eclipse.

7:04 a.m. CST — Sunrise

7:06 a.m. CST — Moonset

While all the stages of the eclipse are not visible from the Chicago area, the events leading up to the total eclipse are easily visible.

The articles that follow provide details about the planets visible without optical assistance (binoculars or telescope):

 

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