April Moon at Perigee


   Our Moon reaches perigee, (closest distance from Earth), for this orbit on Friday April 20th. At that time the Moon will be at a distance of 28.9 Earth diameters (368,714 km or 229,108 miles) from the Earth.

   Does our Moon actually go around the Earth as this graphic shows? From our perspective on the Earth the Moon appears to circle around the Earth. However, in reality, the Moon orbits the Sun together with the Earth*


   On the day of the perigee Moon the 5-day old waxing crescent Moon is above the western horizon. The Moon is about 5o west (to the left) from the open star cluster, M-35.

   *Click here to read my 2006 Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)

   Read this very informative article about the Earth-Moon system and their orbital motions, written by Joe Hanson. “Do We Orbit the Moon?”

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to go to bobs-spaces.

Sun Enters Astronomical Sign of Aries

April 19th   Thursday April 19th the Sun in its apparent eastward motion along the ecliptic, moves out of the constellation Pisces the Fishes and into the constellation of Aries the Ram. This is the true or actual position of the Sun as opposed to the pseudoscience of astrology which usually has the astrological Sun one constellation ahead or east from the Astronomical Sun’s position.
   Read a little more about how astrology has the Sun incorrectly placed in a previous blog, and in another blog discussing the effects of precession.
   
   
   


Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.

Moon and Venus Conjunction


   This week I’m kicking back as ‘they’ say at my brother’s place in Phoenix Arizona. Since my arrival this past weekend the sky has been overcast or very hazy due to strong winds blowing dust and sand. However this evening the skies over Phoenix were clear resulting in this picture of the 2-day young waxing crescent Moon about 5 degrees west from the inner planet Venus as the two set in the west.

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.

April Moon at Descending


   Tuesday April 10th the thin waning crescent 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 (dark green line) has with the ecliptic.
   
   
   


   On the day of the node crossing the 24-day old waning crescent Moon will be over the eastern horizon about an hour before the Sun rises.

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to go to bobs-spaces.

Moon Traverses Taurus


   Wednesday and Thursday evenings March 21st and 22nd the waxing crescent Moon will pass across the constellation of Taurus the Bull. It will first be several degrees from the open star cluster the Pleiades and then the next day the Moon will be within 1-2o from the reddish star Aldebaran and the open star cluster the Hyades. The latter should prove to be a striking sight through binoculars.

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.

Like Ships Passing in the Night

   Over the next week or so the two inner planets will pass by each other coming the closest on the 19th when the two will be less then 4o from each other. With only casual observation one should notice that both planets are moving with respect to each other, but in opposite directions. Mercury is recently past its eastern elongation and is now moving westward, in retrograde, toward the Sun and inferior conjunction. On the other hand, or orbit, Venus is moving eastward out from a recent superior conjunction, opposite side of the Sun, toward its own respective eastern elongation.

   
   
   
   This animated graphic shows Venus and Mercury over a period of several days from March 16th to the 29th of March. The time is set for 7:15 pm CDT and in the first several frames the planets are first shown as they would appear at 7:15 pm, then I added labels, then their respective orbits. To make the animation easier to see I also turned off daylight, and then finally the labels were turned off then back on at the end.
   
   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.

Waxing Crescent Moon in Conjunction with Mercury and Venus


   Sunday evening March 19th the thin 1.5-day young waxing crescent Moon, and the two inner planets, Venus and Mercury, will be over the western horizon about 1 hour after sunset local time. All three will fit within the width of a 7×50 binoculars field of view (about 7o).

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.