August Moon at Ascending Node – and Oh Yeah, A Total Solar Eclipse!

   Monday August 21st the new Moon will be crossing the plane of the ecliptic moving north relative to the ecliptic. This is known as the ascending node, one of two intersections the Moon’s orbital path has with the ecliptic. The ecliptic is actually the Earth’s orbit and the Moon’s orbit is inclined about 6o from the ecliptic. So there are two node intersections, the ascending and descending nodes.

   On August 21st the new Moon will be crossing the plane of the ecliptic at 10:34 UT (5:34 am CDT) within the constellation Leo the Lion. 8 hours later, at 18:30 UT (1:30 pm CDT), the Moon will reach new phase. This close timing between the new Moon phase and a node crossing means only one thing – eclipse!!

   My eclipse viewing area will be at an Elementary School in the North Kansas City School District. From that location totality will be approximately 80 seconds. This short video showing totality for 80 seconds, was clipped and edited from a video shot during the November 2012 total solar eclipse viewed from Australia.

   Read a bit more about this eclipse from a previous post.

      Does our Moon actually go around the Earth as many graphics show? From our perspective on the Earth the Moon appears to circle around the Earth. However, in reality, the Moon orbits the Sun together with the Earth*

   *Click here to read my 2006 Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)

   Read this very informative article about the Earth-Moon system and their orbital motions, written by Joe Hanson. “Do We Orbit the Moon?”

   
   
   

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.

Sun Enters Leo

10aug-view_from-earth
   Thursday August 10th the Sun in its apparent eastward motion along the ecliptic, moves out of the constellation Cancer the Crab and into the constellation of Leo the Lion. 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.
   
   
   

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.

Mars, Phone Home!

mars-solar-conjunction-above   Thursday July 27th the planet Mars will be at solar conjunction, on the opposite side of the Sun from the Earth. Mars will reappear on the west side of the Sun as a morning planet next month and gradually will become more visible in the morning skies.
    So while Mars is out of sight for observers it is also out of ‘radio sight’ for all of the spacecraft at Mars – either on the surface or in orbit. Between July 22nd to August 1st mission controllers will stop sending messages to the spacecraft at Mars, however the orbiters will continue their science observations and collecting data. The rovers on Mars on the other hand will not rove until after the radio silence period, but will still be able to carry on with some investigations.

   Click here to read more about how NASA prepares for the radio silence.

   
   
   
   

   
   
   

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.

July Moon at Ascending Node

   Tuesday July 25th the waxing crescent Moon will be crossing the plane of the ecliptic moving north relative to the ecliptic. This is known as the ascending node, one of two intersections the Moon’s orbital path has with the ecliptic. The ecliptic is actually the Earth’s orbit and the Moon’s orbit is inclined about 6o from the ecliptic. So there are two node intersections, the ascending and descending nodes.

click on graphic to see it larger
   On July 25th the 2.5-day old waxing crescent Moon will be with the constellation Leo the Lion, and the Moon will be located about than 8o from the heart of the Lion, the star Regulus. Very close to Regulus i s the innermost planet Mercury. This should make for a great view with binoculars or through the eyepiece of a telescope.

   Does our Moon actually go around the Earth as many graphics show? From our perspective on the Earth the Moon appears to circle around the Earth. However, in reality, the Moon orbits the Sun together with the Earth*

*Click here to read my 2006 Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)

Read this very informative article about the Earth-Moon system and their orbital motions, written by Joe Hanson. “Do We Orbit the Moon?”

   
   
   

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.

Sun Not In Leo


   According to the pseudoscience of astrology, Saturday July 22nd the sun will be entering the constellation of Leo the Lion. In fact the Sun is still within the boundaries of the constellation Cancer the Crab, having just entered that region two days ago.
   The difference between the two locations of the Sun, the correct astronomical vs. the incorrect astrological, is due to the effects of precession, or more specifically, the precession of the Earth’s axis. The Earth wobbles on its axis like a spinning top does as the top slows down. So, in approximately 26,000 years the Earth will have spun, or wobbled one time. This is a repetitive cycle and over the course of one precession cycle the poles of the Earth trace out a circle against the background stars over their respective pole. any star on or nearest to this precession circle is the pole star. Currently the north pole of the Earth points toward Polaris and within this century, due to precession, will point the closest it will be, and then over time the Earth’s north pole will shift away.
   Another effect of precession has been to cause the celestial grid system to shift moving the original signs of the zodiac by at least one constellation to the west. In other words the Sun is more to the east which in effect means that whatever your zodiacal sign may be according to astrology, you are really the constellation to the west, or before it according to Astronomy.
   Click here to read a little more about precession from a previous blog.
   The Science of Astronomy has its roots in astrology with the origins of astrology beginning several millennia ago possibly by the Babylonians. Regardless of its origins the basis for at least Sun astrology, the popularized version printed in newspapers, is the position of the Sun relative to stars in the background. However we now know that due to the effects of precession the Sun’s position is no longer as it was during the beginnings of astrology.
    The slideshow below shows the sun’s position within Cancer on July 22nd 2016 AD, and then shifts to show the sun in Leo 4,000 years ago on 22 July 2016 BC. Precession has shifted the sun’s position one constellation to the west.

This slideshow requires JavaScript.

   
   
   

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.

Sun Enters Cancer

19july-view-from-earth   Thursday July 20th the Sun in its apparent eastward motion along the ecliptic, moves out of the constellation Gemini the Twins and into the constellation of Cancer the Crab. 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.
   
   
   

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.

Earth at 2017 Aphelion

Earth at Perihelion   Monday July 3rd, as the Earth continues its annual trek around the Sun, the Earth reaches a point in its orbit that is called aphelion. Aphelion is the greatest distance that separates the Earth from the Sun, and we are the furthest from the Sun for the year at this point in the orbit. So, at 20 UT (3 pm CDT) on Monday July 3rd the Earth is 1.01668 AU (94,506,310 miles; 152,093,163 km) from the Sun.
   Approximately one-half year or one-half revolution earlier, on January 4th, the Earth was at perihelion, its minimum distance from the Sun for this year (0.98331 AU (91,404,375 miles; 147,101,082 km). This difference, about 3%, in distances is due to the shape of the Earth’s orbit being elliptical rather than circular. However the Earth has a mildly elliptically shaped orbit that is closer to being slightly out-of-round than the incorrect, very elliptical orbit that is often shown – like the illustration used here.
sun2014-ani   In Astronomy the shape of a planet’s orbit is called eccentricity, with 0 being a circle and 1 a straight line. Any value between 0 and 1 represents an ellipse. The shape of the Earth’s orbit is so close to being circular that the apparent size of the Sun does not appear to change as this animated graphic shows. The difference between perihelion and aphelion is about 3%.

   
   
   
   Eccentricity for each planet is listed below for comparison.

Planet	   Eccentricity	
Mercury	   0.2056
Venus	   0.0068
Earth	   0.0167
Mars	   0.0934
Jupiter	   0.0484
Saturn	   0.0542
Uranus	   0.0472
Neptune	   0.0086
Pluto	   0.2488

   To read more about the Earth’s orbit and get some teaching ideas click here to download a PDF copy of my January 2011 Scope on the Skies column Solar Explorations.

   
   
   

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.