Dance of the Planets Continues

   In a previous post I described how the two inner planets, Mercury and Venus, and an outer planet, Mars, will be visible over the eastern horizon in the hour or so before the Sun rises. Given their respective orbital speeds the three planets will interact with one another in a series of conjunctions that at times will include the star Regulus in Leo the Lion.
   Once again facing east along 50 Highway at around 6 am CDT with early morning traffic just starting to increase. Still dealing with haze and low clouds, some of which are remnants of Hurricane Irma.

   
   
   

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.

Neptune at Opposition – 2017

   Tuesday September 5th the outer planet Neptune reaches a position in its orbit around the Sun when it is on the opposite side of the Earth from the Sun. This coincidentally is known as opposition, and it is an orbital position which only the planets further from the Sun than the Earth may reach.
   At opposition an object orbiting the Sun beyond Earth’s orbit rises and sets in a fashion similar to our Moon when it is at full phase, in that the object at opposition rises at sunset and sets at sunrise.


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 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.

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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.

Jupiter at Eastern Quadrature

1apr-jupiter-east-quad   On Thursday July 6th the position of the planet Jupiter with respect to the Earth and the Sun places the solar system’s largest planet at an orbital position called eastern quadrature. Jupiter is at a 90 degree angle from the Earth as this graphic shows. Think first quarter Moon as that is a fair comparison of the relative positions. At this position Jupiter follows the Sun across the sky from east to west as the Earth is rotating, meaning that Jupiter rises after the Sun and consequently sets after the Sun.

   Where is Jupiter now? This graphic shows the sky at 10 pm CDT to include Jupiter high above the southwestern horizon and east from Leo the Lion and its bright star Regulus. Saturn is further east within a few degrees from the waxing gibbous Moon.

   This is a short 6-7 minute video I made as part of a live musical performance called “Orbit” that was performed at the Gottleib Planetarium in Kansas City Missouri in May 2011. This is a piece from the much longer tour of the solar system performance and video and shows Jupiter, Saturn and some of their moons as viewed from the Cassini spacecraft.

   
   
   

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

July Moon at Apogee

   Our Moon reaches apogee, (greatest distance from Earth), on Thursday July 6th. At that time the Moon will more or less be at a distance of 31.82 Earth diameters (405,934 km or 252,235 miles) from the Earth.
   Does our Moon actually go around the Earth as this graphic shows? 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?”

   On the day of the apogee Moon the 13-day old nearly full Moon, but still in the waxing gibbous phase, rises around local time for sunset and is about 2o from Saturn and around 14-15o degrees from the reddish star Antares in Scorpius the Scorpion.

   
   
   

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.

June Moon at Ascending Node

   Thursday June 27th 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.

   On June 27th the 4-day old waxing crescent Moon will be with the constellation Leo the Lion, and the Moon will be located less than 1o from the heart of the Lion, the star Regulus. This should make for a great view with binoculars or through the eyepiece of a telescope.
   Just above the western horizon, possibly lost in the Sun’s glare, are two more planets – Mars and Mercury about 1o apart.

   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.

Mercury at Superior Conjunction

mercury at superior conjunction
   Wednesday June 21st 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 1.324 AU (123,073,489 miles; 198,067,580 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.