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.

April Apogee Moon

April Apogee Moon   Our Moon reaches apogee, (greatest distance from Earth), on Monday April 8 th. At that time the Moon will more or less be at a distance of 31.68 Earth diameters (404,144 km or 251,123 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 apogee the 22-day old last quarter Moon will be over the eastern horizon at around sunrise local time and within about 11o from the ringed planet Saturn, and about 8-o from Mars.

*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.

A Week of Moon Conjunctions


   Over the next 7 days (mornings) the Moon, as it wanes toward last quarter, will pass closely by several planets and brights stars in some close and some not so close conjunctions.
   Perhaps the best morning will be on April 7th when the near last quarter Moon will be 1-2o from Saturn and about 4o from Mars.
All three will easily fit within the field of view of 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.

Mars and Saturn Conjunction


   Monday morning April 2nd the planets Mars and Saturn will be separated by about 1-2o as they both rise in the east. Both planets are near the Milky Way and within the boundaries of the constellation Sagittarius the Archer.

   
   
   

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.

Mercury at Inferior Conjunction

orbital-positions   Sunday April 1nd the innermost planet Mercury reaches inferior conjunction. At inferior conjunction Mercury will move between the Earth and the Sun – much like the position of the Moon at new phase. The graphic to the right shows the planet positions relative to the Earth and Sun for both inner planets and outer planets.

   While at this inferior conjunction Mercury will not be directly in line with the Earth and the Sun – on the ecliptic. Mercury has an orbital inclination of 7o with respect to the ecliptic. So like our Moon, Mercury during each complete orbit, will cross the plane of the ecliptic moving north (ascending node) and also moving south (descending node). For this inferior conjunction Mercury will be north of the ecliptic.

   
   
   

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.

Saturn at Western Quadrature

saturn-west-quadrature   Thursay March 29th, the position of the planet Saturn with respect to the Earth and the Sun places this ringed planet at what is called western quadrature. Saturn is at a 90 degree angle from us as this graphic shows. Think third quarter Moon as that is a fair comparison of the relative positions. At this position Saturn leads the Sun across the sky from east to west as the Earth is rotating, meaning that Saturn rises before the Sun and also sets before the Sun.

Saturn currently is within the constellation of Sagittarius the Archer as this graphic shows. From the northern hemisphere, looking toward the southern horizon, you can find Saturn to the east, left, from the reddish star Antares. Between Saturn and Antares is Mars, about 2-3o from Saturn. To the right from Antares is the planet Jupiter.

Learn a little (or a lot) about Saturn by visiting the Cassini at Saturn mission web site.
Click here to go to the Cassini Mission web site.

   This is a short 5 minute video I made as part of a live musical performance called “Orbit”. This is a piece from the much longer tour of the solar system performance and video and shows Saturn and some of its moons as viewed from the Cassini spacecraft that month.

   
   
   


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.

March Moon at Ascending Node

   Tuesday March 27th the waxing gibbous Moon will be crossing the plane of the ecliptic moving north relative to the ecliptic. This is known as the ascending node, one of two intersections the Moon’s orbital path has with the ecliptic. The ecliptic is actually the Earth’s orbit and the Moon’s orbit is inclined about 6o from the ecliptic. So there are two node intersections, the ascending and descending nodes.


   On Tuesday evening March 27th the 10.5-day old waxing gibbous Moon will be within the boundaries of Leo the Lion and about 7o west (right) from the ‘Heart’ of the Lion, the star Regulus.

   Does our Moon actually go around the Earth as many graphics show? 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*

*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 return to bobs-spaces.