Moon At Descending Node

21june-desc_node-ani   Saturday 21 June our Moon will be crossing the plane of the ecliptic moving south. This is known as the descending node, one of two intersections the Moon’s orbital path has with the ecliptic.

Click on graphic to see it full size.

Click on graphic to see it full size.

   At around sunrise or earlier Saturday morning look toward the east to see the thin 24-day old waning crescent Moon near the stars of the constellation Aries the Ram. This group of three stars fits nicely within the field of view of most binoculars. Further to the left or north are the stars making up the constellation Perseus the Hero. Of particular interest is the star Algol, an eclipsing binary star system. This star is actually a group of three stars with the second brightest of the trio orbiting in a nearly 3-day orbital period around the brightest star of the trio. When it passes in front of the brightest star the overall magnitude of the brightest star dims from 2nd to 3rd magnitude in about a 10 hour period.
   During the longer winter nights it is possible, if the timing is right, to see the entire magnitude change if one occurs after sunset. If this is early enough then there may be the chance to catch the opposite side of the stellar eclipse before the Sun rises the next morning. On the other if you live north of the Arctic Circle you have all night. Literally!!
   Down toward the northeastern horizon Venus shines brightly with the stars of the Pleiades just to the left from Venus.

Caution: Objects viewed with an optical aid are further than they appear.
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

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