Mercury at Inferior Conjunction

orbital-positions   Thursday April 20th 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.

mercury at inferior conjunction   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). In this situation Mercury is north of the ecliptic and 6 days away from its descending node on April 26th.

   
   
   

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.

Venus at Inferior Conjunction

   Saturday March 25th the inner planet Venus reaches its orbital position known as inferior conjunction.
   This is one of four points along an inner planet orbit. At inferior conjunction Venus is between the Earth and the Sun – sort of like our new Moon phase – but not necessarily directly in line. If that were so, inferior conjunction at the same time as Venus in direct line with the Earth and Sun (a node crossing at inferior conjunction) it would be a somewhat rare transit of the Sun by Venus. These happen as a pair of transits about one time each century with the last pair of Venus transits in June 2004 and June 2012. Here are some pictures of the June 2012 Venus Transit. Here is a link to the Vimeo web site to watch a video of the 2012 Venus Transit.
   By the way the next pair of Venus Transits are December 2117, and December 2125.

    At this inferior conjunction Venus is north of the ecliptic heading south toward its descending node and ecliptic crossing next 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.

Mercury at Inferior Conjunction

orbital-positions   Monday September 12th 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.

mercury at inferior conjunction   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). In this situation Mercury is still south of the ecliptic but heading toward its ascending node on September 23rd.

   
   
   

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.

Mercury Begins to Retrograde


   Friday April 29th the innermost planet Mercury starts its retrograde motion as it moves away from its recent eastern elongation toward inferior conjunction, a node crossing, and a transit of the Sun on May 9th.

   
   
   

Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Mercury at Descending Node

feb11-desc-node   Wednesday February 11th the innermost planet Mercury crosses the plane of the ecliptic, Earth’s orbit, moving south in what is called a descending node. The orbit of Mercury is inclined about 7o from the the ecliptic setting up both a descending node as well as an ascending node approximately one-half orbit later.
   The next time Mercury is at descending node it will coincide with Mercury at inferior conjunction. This will set up a transit of the Sun by Mercury.

   
   
   
   

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.

Mercury North of the Ecliptic

mercury-orbit   Monday January 18th the innermost planet Mercury will reach its greatest angle above the ecliptic at 7o North. The plane of the ecliptic, or the Earth’s orbital path around the Sun, is the reference ‘line’ for measuring each planet’s respective orbital path angle from. This is known as inclination and Earth’s has an inclination of 0o while Mercury has an inclination of 7o.
   Mercury was recently at inferior conjunction, between the Earth and Sun (like a new Moon phase) but due to the 7o inclination for Mercury’s orbit it was not directly between the Earth and Sun on the ecliptic. This inclination of Mercury’s orbit, like the Moon’s 6o inclination from the Ecliptic, means that not every new Moon or inferior conjunction of Mercury results in either a solar eclipse or a Mercury transit.
   As Mercury and the Earth continue revolving around the Sun the angular difference between the two orbits will change as Mercury’s orbit criss crosses the ecliptic in its regular pattern of ascending and descending nodes. Keep track of these as on May 9th, at descending node, Mercury will transit, cross the disk of the Sun in a Mercury transit.

   
   
   
   

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.

Mercury at Inferior Conjunction

orbital-positions   Wednesday September 30th 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.

mercury at inferior conjunction   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).

   
   
   
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.