January Moon at Ascending Node

15jan-ascending-node   Sunday January 15th the waning gibbous 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 January 15th the 16-day old waning gibbous Moon will come within about 1o from the star Regulus in Leo the Lion.

   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.

Mars and Uranus at Heliocentric Conjunction

   Greetings from San Carlos de Bariloche, Argentina. For the next 3 weeks I will be posting with the perspective of viewing the sky from between around 42o-48o south latitude, and then from the equator while in Quito Ecuador.

   On the evening of January 13th both planets, Mars (23o) and Uranus (23o), will be at about the same heliocentric longitude or at heliocentric conjunction. While they may share nearly identical heliocentric longitude coordinates they do not have the same right ascension with Uranus about 2 hours of R.A. west from Mars. Both Mars and Uranus are visible over the southwestern horizon a couple of hours after sunset, although it may prove to be difficult to see Uranus with an apparent magnitude of nearly 6.0.

   
   
   

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.

Jupiter at Quadrature ——— Venus at Elongation

   Thursday January 12th the gas giant planet Jupiter reaches the point along its orbit around the Sun where Jupiter would be described as being at western quadrature. It is at a 90o angle relative to the Earth and the Sun.
   Also on this day the inner planet Venus reaches a point in its orbit known as eastern elongation. This puts Venus at somewhere around a 90o angle relative to the Earth and the Sun when viewed looking down from above the solar system but Venus is on the other side of the Sun from where Uranus is currently located.
   In terms of elongation Venus is 47.2o to the east of the Sun. In terms of viewing angle you are the point of a triangle with Venus at the left base corner and the Sun at the right base corner. The angle between the Sun and Venus is the elongation angle, and at 47.2o Venus sets around 3 hours after sunset as its seting motion or speed is (15o per hour based on Earth rotation rate.
   Where is Jupiter currently? Jupiter rises around midnight local time and is located high above the southern horizon at sunrise local time near the blue-white star Spica in Virgo the Harvest Maiden.
   And Venus? Can’t miss this planet as it is the brighest stellar object 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.

January Moon at Perigee

10jan-perigee_moon   The Moon reaches perigee, (minimum distance from Earth), this month on Tuesday January 10th. At that time the Moon will more or less be at a distance of 28.4 Earth diameters (363,238 km or 225,705 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*

   On the day of the perigee Moon 13-day old nearly full Moon rises just before sunset local time and is located near the feet of the Gemini Twins.

   
   
   *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.

Uranus at East Quadrature

   Tuesday January 10th the position of the planet Uranus with respect to the Earth and the Sun places this ringed planet at what is called eastern quadrature. Uranus is at a 90 degree angle from the Earth as the banner graphic at the top of this page shows. Think first quarter Moon as that is a fair comparison of the relative positions. At this position Uranus follows the Sun across the sky from east to west as the Earth is rotating, meaning that Uranus rises after the Sun and sets after the Sun.

   Can’t find Uranus? The 7th planet from the Sun is currently within the constellation of Pisces the Fishes. Finding Uranus is somewhat of a challenge given that it has an average apparent magnitude of 6, putting it at the naked-eye limit of visibility. However the planet is visible with binoculars as a faint pale-bluish star and its location may be found by using the corners of the Square of Pegasus as ‘pointer stars’. With some planning and a good finder chart like those from the Sky Live web site an observer could make an observation perhaps once a week and follow the motion of the Uranus amongst some of the stars of Pisces.

   This is a short piece from a video I made as part of a live musical performance called “Orbit” that I was part of in May 2011. This is a piece from the much longer tour of the solar system performance and video and shows Uranus and some of its moons as viewed from the Voyager 2 spacecraft.

   
   
   

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.

Moon Gets Nosed by the Bull

   Sunday January 8th the 11 day old waxing gibbous Moon will be a few degrees from the nose of Taurus the Bull, and the stars making up the open star cluster the Hyades.
8jan-bino  Through 7×50 binoculars the stars of the open star cluster the Hyades and the Moon will make for an interesting sight.

   
   
   
   
   
   
   

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.

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.