Uranus No Longer Backing Up

   Well that’s a relief!

July 22nd to December 22nd :  Uranus at 30-day intervals

July 22nd to December 22nd : Uranus at 30-day intervals


   Monday December 22nd the outer planet Uranus ends its retrograde motion and resumes its eastward, or direct motion. Uranus begun this current retrograde motion last July 22nd. Retrograde motion is an apparent motion to the west that any outer planet relative to the Earth appears to do whenever the faster moving Earth passes by. Sort of like passing a car on the highway. You know both vehicles are moving in the same direction but from your perspective it could appear that the other car is moving backward as you go by. Regardless, retrograde motion for the outer planets happens at regular intervals as the Earth pass each one. It is always more than a year and always a little further to the east when the retrograde motion begins each time. This is because the outer planet is also moving eastward.

   
   
   

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.

A Comet, the Moon, and Mars

       And no, this is not the first line in a joke sentence ending with “walk into a bar!”
       Seriously Comet Finlay (16/P), a regular visitor to the inner solar system has been reported to have significantly brightened from 11th magnitude to between 8th and 9th magnitude. According to reports the comet is typically at around 11th magnitude as it approaches perihelion, December 27th. So at 8th or 9th magnitude this puts the comet at a brightness within the reach of large aperture binoculars – at least 10×50 or larger. 25 mm with 8" DobsonianAnd certainly within the reach of telescopes.
       On the 24th the comet will be passing very close to Mars as we view them from Earth. This is a line of sight effect not one where the comet literally and physically comes close to Mars. This should be a fine pairing of celestial objects, especially when viewed through the eyepiece of a telescope as shown in this simulated view using a 25 mm eyepiece with an 8″ Dobsonian telescope.
    finlay-ani   Prior to the 24th you can follow the comet in real time on an interactive star map at the The Sky Live web site. This is a really useful web site for tracking more than just comets. The display may be set to a Planetarium, star chart, or a Live Position mode. With the Planetarium setting you can adjust the date and time and view the comet’s motion relative to the constellation and stars in the background.
    Click on graphic to see it full size.

    Click on graphic to see it full size.

       On December 24th, shortly after sunset local time, look for the thin waxing crescent Moon to be just off to the right from Mars and the comet.

       
       
       

    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.

Sun Not in Capricornus aka the December Solstice

  According to the pseudoscience of astrology the Sun enters the constellation of Capricornus the Sea Goat on Sunday December 21st, when in fact the actual position of the Sun is still within the boundaries of the constellation of Sagittarius the Archer.

Click on graphic to see it full size.

Click on graphic to see it full size.

   In reality on Sunday December 21st at 23:03 UT, 5:03 pm CST, the Sun will have reached the celestial coordinates of 23.5o degrees south; 18 hours right ascension. With regard to the Earth’s surface this places the Sun over the Tropic of Capricorn, which is also 23.5o south. We know that this signals the start of northern hemisphere winter and the southern hemisphere summer seasons. We also know that it is the Earth’s tilt on its axis that is the cause for seasons on Earth rather than the distance between the Earth and the Sun.
   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.

   
   
   

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.

Waning Crescent Moon Near Saturn

Click on graphic to see it full size.

Click on graphic to see it full size.


   Friday December 19th the thin waning crescent Moon is within a few degrees from the planet Saturn. The two rise around 5 a.m. local time and will make a nice contrast when viewed through binoculars.

   
   
   

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.

Sun Enters Sagittarius

16dec-view-from-earth   Thursday December 16th at 13 UT (7 am CST) the Sun in its apparent eastward motion along the ecliptic, moves out of the constellation Scorpius the Scorpion and into the constellation of Sagittarius the Archer. 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.
   
   
   

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.

Triangulate to Mars

Click on graphic to see it full size.

Click on graphic to see it full size.


   Wednesday evening, December 17th, the planet Mars sits low above the southwestern horizon at sunset. Mars is not particularly bright and it may be difficult to pick out amongst the stars in that part of the sky. However the three bright stars that make the asterism known as the Summer Triangle are over the western horizon forming a right triangle. Imagine a line extending east from the lower side of the triangle, from Vega to Altair, and you will point at Mars as this animated graphic shows.

   
   
   

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.

Moon At Ascending Node

16dec--ascending-node
On Tuesday December 16th our Moon will be crossing the plane of the ecliptic moving north. This is known as the ascending node, one of two intersections the Moon’s orbital path (dark green line) has with the ecliptic.

Click on graphic to see it full size.

Click on graphic to see it full size.

Look for the 24-day old waning crescent Moon to rise a few hours before sunrise near the bright bluish-white star Spica.


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.