Sunday, August 4, 2013

Moon with Morning Planets

  The old Moon (two days before New Moon) provided an attractive target in the east this morning but it wasn't alone.  It was accompanied by not one....not two..... but three planets 

   Above the Moon and easiest to see is the king of planets, Jupiter.  Just to the Moon's upper left is faint Mars, which like Jupiter is just starting to appear in the morning sky as the Earth is set to overtake them in their race around the Sun.  Mars is currently only 27 degrees from being on the exact opposite side Sun.  The third planet in the photo is the elusive Mercury.  It appears to the lower left of the Moon.  While the Earth is undefeated in its racing career versus Jupiter and Mars, it does not come close to beating Mercury which zips around the Sun completing one orbit every 88 days.

Planet positions indicated

Cropped photo shows planets more clearly

Cropped photo with answers.
  In the photo you'll notice that the whole Moon can be seen with the crescent shape brightly illuminated.  While the Crescent shape is due to the Moon being backlit for the most part as it is only two days from positioning itself between the Earth and Sun,  what is illuminating the rest of its disk?  ......................The Earth.  If you were standing on the dimly lit part of the Moon you would see an almost Full Earth dominating the night sky.  The Full Earth appears 42-100x brighter from the Moon than the Full Moon does from the Earth because the Earth's diameter is more than 3.5x larger than the Moon's (covering more than 12x greater area) but the Earth is also at least 3x more reflective (depending on cloud cover).
   Jupiter and Mars will be rising a little earlier every day until reaching opposition (when the Earth passes between them and the Sun) and they will be visible all night. For Jupiter that occurs on January 5, 2014.  Mars being closer to the Sun than Jupiter has a velocity closer to Earth's speed so it takes Earth longer to to lap it.  Its opposition doesn't occur until April 8, 2014.  Mercury is getting lower each morning and will be on the opposite side of the Sun on August 24.  The Moon may be visible much lower tomorrow morning and will be in line with the Sun on Tuesday and not visible until later in the week when it returns to the evening sky as a thin crescent low near the horizon.


  1. Thanks. I couldn't even see Mars with my eyes but I knew where it was and I figured the camera would catch it.