A Sky Full of Planets

   Friday August 3rd all of the planets, except for Mercury, and some of the Dwarf Planets will be over the horizon during the hours before sunrise and the hours before sunset. The dwarf planets Pluto (14.2), Haumea (17.2), Makemake (16.7), and Eris(18.5) with low apparent magnitudes are too distant to be visible other than with larger aperture telescopes. However Dwarf Planet Ceres, at 8th magnitude could be visible with smaller telescopes and certainly with long exposure time imaging.

   
   
   

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.


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Pluto Ducks Behind the Sun

7jan
   Saturday January 7th the Dwarf Planet Pluto reaches a point in its orbit where it is on the opposite side of the Sun as viewed from Earth. This is known as solar conjunction.

   
   
   

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.

Our Moon Near Dwarf Planet Pluto


   Wednesday morning May 25th the 18.5-day old waning gibbous Moon will be about 3o from Dwarf Planet Pluto. Given that the Moon has an apparent magnitude of -18.5 not much else will be visible in the surrounding area of the sky, despite what my graphic shows.

   However a 2nd magnitude star, Albaldah (in Sagittarius), is about 0.5o from Pluto. If you can see that star then you are in effect looking at Pluto also, as this simulated 25mm eyepiece view is showing.

   
   
   
   
   

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

Mercury at Aphelion

mercury at aphelion   Sunday February 21st the innermost planet Mercury reaches aphelion, its furthest distance from the Sun, 0.4667 AU, (69,817,326 km; 43,382,475 miles). Interestingly, I suppose, is that the next time Mercury reaches aphelion will be May 19th, 10 days after the Mercury transit of the Sun.

   All planets orbit the Sun with an orbital shape that is not circular but rather elliptical. How much away from being a circle is called eccentricity of an orbit. With 0 representing a circle and 1 a straight line Mercury, with an eccentricity of 0.2056, has the greatest eccentricity of the other 7 planets. The dwarf planet Pluto, for comparison, has an eccentricity of 0.2488.

   
   
   
   

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.

Pluto Shifts Out Of Reverse

   Thursday September 24th the second largest of the known Dwarf Planets, Pluto, ends its apparent retrograde motion and resumes its regular direct or eastward motion in its 248 year (Earth years) long revolution around the Sun. Retrograde motion is an apparent westward, or backward motion relative to the regular eastward orbital motion nearly all solar system Sun orbiting objects follow. Any of these objects further from the Sun than the Earth seem to slow down, stop, and then reverse their direction for a period of time lasting from several days to a few weeks. The apparent reverse in direction, retrograde motion, happens as the faster moving Earth passes by the more distant object.
inner-planets   While retrograde motion is generally thought of in terms of outer planets the two inner planets, Mercury and Venus, also have retrograde motion but not as a result of the Earth’s orbital motion. From eastern elongation through inferior conjunction to western elongation these two inner planets move westward. And then from western elongation through superior conjunction to eastern elongation they move 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.

Moon – Pluto Conjunction

click on graphic to see it full size   Wednesday July 29th the waxing gibbous Moon will be within a few degrees from the Dwarf Planet Pluto.
   Where is Pluto and is Pluto visible to the naked eye? Pluto currently is above the teapot-shaped asterism for Sagittarius the Archer. It is located near a 3rd magnitude star, Xi2 Sagittarii, however Pluto has an apparent magnitude of 14.0 making it too dim to be seen in other than a large telescope or with a sequence of pictures of the same part of sky over a period of several days or weeks. From that sequence of pictures the motion of Pluto against the stars in the background becomes noticeable.

Click here to learn more about the New Horizons mission and take part in the mission with some of the interactives created by NASA.

   
   
   
   

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.

Far Out!

On Tuesday July 14th the New Horizon spacecraft makes it one and only flyby of Pluto coming the closest at 6:49 am CDT (11:49 UT) with a distance of 12,500 kilometers (7,750 miles). As it passes through the Pluto system that includes the dwarf planet Pluto, and 5 known moons the spacecraft will be traveling at approximately 14 km/second (31,000 miles per hour.)

NASA’s New Horizons web site
Pluto at Opposition
What’s Your Pluto Time?

Watch this short song/video written and performed by Dani Robinson, a student in my Astronomy class, this past year.

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.