November Moon at Apogee

   Our Moon reaches apogee, (greatest distance from Earth), for this orbit, on Thursday November 7th. At that time the Moon will be at a distance of 31.75 Earth diameters 251,693 miles (405,060 km) from the Earth.

   On the day of the apogee Moon the 11-day old waning gibbous Moon rises during mid-afternoon and sets later the following morning.

   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)

   
   
   

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Visualize the Ecliptic

Above the Terrestrial Planets this Month

   Once in a while the planets are arranged such that they are spread across the sky. The planets are not lined up in a straight line outward from the Sun but rather are arranged along the ecliptic. The ecliptic is the Earth’s orbital path around the Sun and the respective orbit of each planet is inclined from the ecliptic. And this is one of those times when it is easier to visualize the ecliptic. (see graphics below) Click here to read a previous posting about the ecliptic and planet inclination.

   As the animated graphic is showing the terrestrial planets are not arranged in a straight line. This graphic shows the solar system out to Neptune and from this perspective the planets are obviously not in a straight line.


   
   
   

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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Uranus at Opposition – 2019

view-from-uranus
   Monday October 28th the outer planet Uranus 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 the outer planet rises and sets in a fashion similar to our Moon when it is at full phase, in that the outer planet at opposition rises at sunset and sets at sunrise.

   On the date of the opposition Uranus will be over the eastern horizon after sunset and currently with an apparent magnitude of between 5 an 6 Uranus may be visible with binoculars and certainly with a telescope.

   
   
   

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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When the Moon Hits Your Eye

Thursday evening October 17th look for the 19-day old waning gibbous Moon to be rising with the stars of the open star cluster the Hyades. The Moon will be about 3-4o from the reddish star Aldebaran. Aldebaran represents the ‘angry eye’ of Taurus the Bull, and is at the end of the v-shaped asterism, the Hyades.

   
   
   

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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Along the Ecliptic

   Every once in a while the planets arrange themselves along the horizon and when that happens visualizing the ecliptic is somewhat obvious. For the next week or so all of the naked-eye visible planets except Mars, plus Neptune and Dwarf Planet Ceres, will be above the horizon at sunset local time. If you wait about an hour the Moon and the planet Uranus will rise above the eastern horizon as Mercury and Venus have set in the west.
   The ecliptic is actually the Earth’s orbit and it is used as a reference ‘line’, properly known as the plane of the ecliptic, for all of the Sun orbiting objects. Since few if any Sun orbiting objects have orbits that are on the same plane as the Earth but rather these objects are tilted or inclined either above or below the plane of the ecliptic. This is know as inclination. (Table Source: https://en.wikipedia.org/wiki/Orbital_inclination)

   
   
   

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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Waning Crescent Moon Passes Uranus

   Thursday and Friday mornings before the Sun rises look toward the eastern horizon for the 24-day old waning crescent Moon to be within about 8-9o to the west from the outer ringed planet Uranus on Thursday the 27th, and about 7-8o from Uranus but now to the east on Friday the 28th.


   Uranus has an apparent magnitude 5.84 which technically makes it naked-eye visible (in dark skies) however nearby is the thin waning crescent Moon outshining Uranus with a -11.00 apparent magnitude. Worth mentioning but not naked eye visible is the outermost of the 8 planets, Neptune, with a 7.90 apparent magnitude.

   
   
   

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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June Moon at Apogee

   Our Moon reaches apogee, (greatest distance from Earth), for this orbit, on Sunday June 23rd. At that time the Moon will be at a distance of 31.71 Earth diameters 251,374 miles (404,548 km) from the Earth.

   The 20-day old waning gibbous Moon rises around midnight local time and sets later that same day.

   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?”

   
   
   

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.


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