Mercury at Superior Conjunction

mercury at superior conjunction   Tuesday March 7th the innermost planet Mercury reaches superior conjunction – on the opposite side of the Sun from the Earth. For those that are curious, Mercury at superior conjunction is approximately 1.363 AU (126,698,765 miles; 203,901,898 km) from the Earth – the combined distance of the Earth to Sun distance plus the radius of Mercury’s orbit.
   Mercury is not visible while in conjunction with the Sun but within the next week or so Mercury will reappear on the east side of the Sun and start becoming visible over the western horizon at sunset.

   
   
   

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 Near Pluto

(posting this ahead of time – on the road back to Quito and no Internet for a couple of days)

   Sunday morning January 29th the innermost planet Mercury will be about 1o from the the former outermost planet and now a Dwarf Planet, Pluto. Mercury with an apparent magnitude of -0.18 far outshines the 14.19 apparent magnitude of Pluto.
These two graphics show the sky as viewed from Quito Ecuador at 0o latitude, and my home latitude of approximately 40o North.

   
   
   

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 Western Elongation

19jan-mercury-east-elongation
   On Thursday January 19th Mercury, the innermost planet, will reach its orbital position known as greatest western elongation at 24.1o. At that moment Mercury, the Sun, and the Earth, would be arranged in something close to approximating a right angle as this graphic shows. Even though it sounds confusing at western elongation for either Mercury or Venus the inner planet will be to the right of the Sun as we view them, meaning that at western elongation an inner planet rises in the east before the Sun rises. And at eastern elongation with the inner planet on the left side of the Sun the inner planet follows the Sun across the sky setting after the Sun sets.
orbital-positions
   From our perspective the orbits of Mercury and Venus appear to move from one side of the Sun to the other – out to the left (east) from the Sun to eastern elongation, then reverse and move westward (inferior conjunction) between the Earth and the Sun to western elongation. From there the inner planet moves eastward going behind the Sun (superior conjunction) and eventually reappearing on the eastern side of the Sun for an eastern elongation. Repeat over and over – do not stop!
   Mercury is visible in the morning skies before sunrise as these graphics show.


   
   
   
   
   

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   Wednesday December 28th 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 after its recent ascending node on December 20th.

   
   
   

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 East Elongation

orbital-positions    On Sunday December 11th Mercury, the innermost planet, will reach its orbital position known as greatest eastern elongation. At that moment Mercury, the Sun, and the Earth, would be arranged in something close to approximating a right angle as this graphic shows.
   From our perspective the orbits of Mercury and Venus appear to move from one side of the Sun to the other – out to the left (east) from the Sun to eastern elongation, then reverse and move westward (inferior conjunction) between the Earth and the Sun to western elongation.
click on animated graphic to see it larger    From there the inner planet moves eastward going behind the Sun (superior conjunction) and eventually reappearing on the eastern side of the Sun for an eastern elongation. Repeat over and over – do not stop!
   This animated graphic shows Mercury at its eastern elongation and its orbital path. The horizon is removed in one graphic so Mercury’s orbit around the Sun could be visualized better.

   
   
   
   

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.

A Planet Buffet

   Friday night December 9th offers up a planet buffet featuring eight planets above the horizon and one under your feet. As this graphic shows one of the outermost of the 8 planets, Uranus, is above the eastern horizon as are two Dwarf Planets, Ceres and Eris, and the waxing gibbous Moon. Further west over the southern horizon is the outermost of the 8 planets, Neptune, and over the southwest horizon are Mars, Venus, Pluto, and Mercury. And under your feet? Look down to see the Earth – can’t miss it!
   Ceres is the closest Dwarf Planet to us as it is within the main asteroid belt between Jupiter and Mars. The other Dwarf Planet is Eris which at 96 AU is located much further than Ceres (2.2 AU) and Uranus (19.4 AU) and Neptune (30 AU).

   
   
   

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 Near Venus

   Friday evening December 2nd the thin 3.5-day old waxing crescent Moon will be about 7-8o from the inner planet Venus. Several other planets are also visible above the horizon. At the time the graphic is set for, 5:30 pm CST, the planet Saturn has just set, Mercury is within about 30 minutes from setting, and Mars shines within the constellation of Capricornus the Sea Goat.
   Not visible to the naked eye, but part of the picture, is the outermost of the 8 planets, Neptune.

   
   
   

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.