May Moon at Ascending Node

   Sunday May 20th 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 Sunday evening May 20th the 5.5-day old waxing crescent Moon will be just within the boundaries of Leo the Lion and about 14o west (right) from the ‘Heart’ of the Lion, the star Regulus.

   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.

Moon Conjunction with Venus


   Last evening, 17 May, the 2.5-day young waxing crescent Moon was in conjunction with the inner planet Venus.
   Canon EOS Rebel T7i: 163 mm; f/9; 0.8 sec.; ISO-400

   
   
   
   Canon EOS Rebel T7i: 135 mm; f/7.1; 0.6 sec.; ISO-400

   
   
   
   
   
   

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.

May Perigee Moon in Conjunction with Venus

   Our Moon reaches perigee, (closest distance from Earth), for this orbit on Thursday May 17th. At that time the Moon will be at a distance of 28.52 Earth diameters (363,800 km or 226,055 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*

   Thursday evening May 17th, shortly after sunset local time (8:26 CDT), look toward the western horizon for a conjunction between a thin 2.5-day young waxing crescent Moon and the inner planet Venus. The two will be about 5.5o apart. The respective apparent magnitudes of Venus (-3.95), and the Moon (-10.22) will make an interesting contrast. Despite the difference in the apparent magnitude of Venus and the Moon, which one appears brighter? Do they appear to be similar in apparent magnitude, or brightness?


   Using binoculars the Moon and Venus will be seen as forming the base of a small triangle with the open star cluster, M-35 (apparent magnitude 5.5) forming the point of the triangle.
   (the size of Venus and Moon are not to correct scale and in this graphic have been enlarged for the image)

   *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.

Sun Enters Taurus

view-from-earth-may   Monday May 14th the Sun in its apparent eastward motion along the ecliptic, moves out of the constellation Aries the Ram and into the constellation of Taurus the Bull. 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 return to bobs-spaces.

Moon in Conjunction with Mercury and Uranus

   Sunday morning May 13th the 27-day old thin waning crescent Moon and the planets Mercury and Uranus will be in a grouping that will fit within a binocular field of view. All three rise about 1 hour before sunrise.
   This may also be an opportunity to see a crescent Moon that is within about 1 1/2 days from its new Moon phase.

   
   
   

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 So Close, but Yet So Far

   Thursday 10 May the outer giant ringed planet Jupiter will be at perihelion, its closest to the sun for this orbit. At perihelion, which coincidentally is 1 day after it was at opposition, Jupiter will be approximately 4.4 AU (658,230,631 km; 409,005,551 miles) from the Sun. With Jupiter this close to its opposition the planet will be rising at around sunset local time and will be visible during the night, and setting at around sunrise local time. Joining Jupiter in the morning skies are the planets Saturn and Mars, as well as the waning crescent 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.

Jupiter at Opposition- 2018

Zooming in on Jupiter at Opposition   Wednesday May 9th at 0 UT, (Tuesday May 8th at 7 pm CDT), the outer giant ringed planet Jupiter reaches the point in its orbit around the Sun that places the Earth in between Jupiter and the Sun. This is known as opposition, and opposition is an orbital position that applies to solar system objects (outer planets, dwarf planets, asteroids, comets, etc.) orbiting the Sun beyond the Earth’s orbit. An object at opposition will have approximately the same heliocentric longitude as the Earth’s heliocentric longitude. So on Tuesday both planets will have a heliocentric longitude of around 228o.
   An opposition of Jupiter occurs approximately every 13 months because both Earth and Jupiter are moving. After one Earth Revolution, an Earth year, the planet Earth will be where it was the previous year at opposition with Jupiter. However Jupiter will not be there because it has moved during the past year as well. It will take the Earth about an extra month or so to catch up with Jupiter. Earth moves 360o each year while Jupiter moves approximately 12o each Earth year.
Sunset Local Time Sunset Local Time.
   When an object is at opposition it rises at approximately the same time as local sunset and that same object at opposition sets at approximately the time of local sunrise. In other words an object at opposition will be up all night from sunrise to sunset.
   Picture our Moon at full phase and how it is directly opposite the Sun, with the Earth in between. The full Moon in effect is at opposition but we call it the full Moon instead. And so both the full Moon and Jupiter at opposition, rise at sunset, set at sunrise, and both will be visible all night.

   
   
Take a brief tour of the Jovian (Jupiter) system. Music by Dark Matter.
Live recording of music written by Richard Johnson. Video by me!

   
   
   

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.