Moon close to Scorpious' head-stars

Event Date: January 8th

Time: 6:00 PM

Brief

  It is interesting when the Moon occults stars-- particularly if they are 1st magnitude and/or bright enough to see with the eye alone before or after occultation.  With a crescent Moon, these occultations are even better because the Moon doesn't wash out dimmer stars.  Also, it is fun to see the Moon pass between two stars.  Whether it be through binoculars or just the eyes, these pass-bys remind us of the precession of the nodes, for the Moon and its orbit.  As shown below, we see a zoom-out and 30º zoom-in of the Moon, after passing between Dschubba and Graffias: two stars of Scorpious' head.  The creature is now rising in the east about two hours before Sunrise.  The first image shows the Moon's orbit and the stick figure of Scorpious' head and body, being above the horizon, and the second image the second emphasizes its head-stars.

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

  We have talked about the nodes' precession several times this year, and how such leads to a limited number of star-passbys.  That [number] depends on where the Moon is in its orbit and whether close or far from the nodes.  As shown in image one, the ascending node-marker is not far west of the Moon's position.  Since the node is moving from east to west, it means that for the upcoming months, the ecliptic latitude of the Moon at that [celestial] longitude will increase.  Later in the year, it will occult Graffias, as seen in various parts of the world. Those that see the occultation being those that have the Moon and star above the horizon and easily visible.  Since the *Moon's sidreal period puts it near/at that part of the sky at a different hour each month, there are times when we could see a (near) occultation, and other times when time zones on the other side of the world--from where we are viewing--see it instead.  Either way, enjoy the pass-bys when you don't see the occultation, as they make good binocular and telescopic viewings as well!

*as opposed to the 29 1/2 day synodic month