Venus – Crescent Moon Conjunction


   Tuesday morning June 20th the 25-day old waning crescent Moon will be about 6o from the inner planet Venus. At -4.6 apparent magnitude Venus contrasts well with the Moon’s -11 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.

Neptune Backs Up

Two days in a row! Like the song goes, “slow down you move too fast” – or proofread!!
   Friday June 16th the outermost of the 8 planets, Neptune, ends its westward retrograde motion around the Sun and will resume direct motion, moving eastward will come to an apparent halt in its eastward or direct motion and appear to start moving backward to the west in what is known as retrograde motion. In this graphic the location of the 21.5-day old waning gibbous Moon is shown to be about 2-3o from Neptune. Neptune has an apparent magnitude of nearly 8.0 making it all but only visible with telescopes – and certainly not on this date with -12th magnitude Moon nearby.

   Retrograde motion is an apparent motion that the outer planets, relative to the Earth, have. It is an apparent motion that looks as if the outer planet stops it normal direct motion to the east and reverses direction to the west. After a period of time the apparent westward motion ends and the planet resumes its normal orbital path to the east. Retrograde motion happens as the faster moving Earth catches up with and then passes by the outer planet. It is during this time that the backward apparent motion happens.

   The two inner planets also have retrograde motion but it is a result of their orbit around the Sun and not the Earth passing them by. For approximately one-half of their orbit they move east, from western elongation through superior conjunction to eastern elongation. Then at eastern elongation the inner planet starts moving westward through inferior conjunction to western elongation.

   Read a little more about retrograde motion in my February 2012 Scope on the Skies column, drawkcab planets, in Science Scope Magazine.

   
   
   

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.

June Moon at Descending Node – Conjunction with Neptune

My Bad! This should have been about Friday the 16th.
2jan-descending-node
   Thursday June 15th the 21.5-day old last waning gibbous Moon will be crossing the plane of the ecliptic moving south. This is known as the descending node, one of two intersections the Moon’s orbital path (dark green line) has with the ecliptic.
   


   On the day of the node crossing the waning gibbous Moon will be over the southeast horizon at around 2 am CDT. The Moon will be in conjunction, and within about 2o from the outermost, (8th), planet Neptune.
   
   
   
   

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.

ISS Followed the Arc

   Last evening, Sunday June 11th the ISS, International Space Station orbited over my part of the world. The ISS appeared about 45o above the west-northwest horizon and followed a path that went below the bowl of the Big Dipper and in a straight line ‘followed the arc to Arcturus’ in the constellation Bootes the Herdsman. At its peak the ISS reached nearly the zenith and at its brightest had to be at least -3.0 in apparent magnitude. After a several minutes the ISS moved out of sunlight and faded from view above the southeastern horizon.
Camera settings were 18mm; ISO 800; F4.0; 2 sec.
   One dependable and accurate source of viewing information for the ISS is at NASA’s ISS Sightings web site. Here you may learn the time and direction the ISS will appear, its duration of visibility, and its time and direction it will stop being visible.

   In a similar manner the Heavens Above web site will also provide viewing information for the ISS but in addition it will display a star map showing the path across the sky. This sample graphic shows the ISS path for June 12th.

   Want to see what the Earth looks like from the ISS? Click on this link to go to the ISS HD Earth Viewing web site for a view from one of several cameras mounted on the ISS as this screen capture shows. There are two additional maps that show the current position and orbital path of the ISS.
   
   
   

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 / Saturn Conjunction and Jupiter Pauses Briefly

   Friday June 9th one of the outer planets, Jupiter, becomes stationary in its retrograde westward orbital motion around the Sun. It will now begin moving in direct motion, its orbital direction around the Sun toward the east – as we view it from the Earth. Jupiter’s retrograde motion is something that occurs to varying amounts as the Earth passes by each outer planet.
   This animated graphic is set to show the motion of Jupiter from early May through the end of June. At the start the graphic shows where Jupiter is relative to the star Spica, and then it zooms in to make the retrograde loop for Jupiter easier to see.
   The Earth passing by an outer planet is a result of the Earth having a faster orbital speed, and as the angles between Earth and an outer planet change there is the appearance of the outer planet slowing down and stopping its regular eastward motion. Then for a time ranging from a week or so to several months the outer planet appears to be moving backward or toward the west. After a time the planet resumes its eastward motion.

   On Friday the 9th the just past full Moon, a 15-day old waning gibbous Moon, will be rising about an hour after local time for sunset. Between 2-3o to the right, or west, from the Moon is the planet Saturn as this graphic shows.

   
   
   

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.

June Moon at Apogee


   Our Moon reaches apogee, (greatest distance from Earth), on Thursday June 8th. At that time the Moon will more or less be at a distance of 31.85 Earth diameters (406,401 km or 252,526 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 14-day old full Moon rises around local time for sunset and is 9-10o 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.

Neptune at Western Quadrature

orbital-positions   On Sunday June 4th the position of the planet Neptune with respect to the Earth and the Sun places this ringed planet at what is called western quadrature. At that orbital position Neptune, and actually any outer planet, is at a 90 degree angle from us as this graphic shows. Think third quarter Moon as that is a fair comparison of the relative positions. At this position Neptune leads the Sun across the sky from east to west as the Earth is rotating, meaning that Neptune rises before the Sun and also sets before the Sun.

click on graphic to see it larger   Neptune currently is within the boundaries of the constellation Aquarius the Water Bearer. At around 7th magnitude Neptune is too dim to see with the naked-eye but easily seen with a telescope or binoculars. In 7×50 binoculars Neptune may be visible near the 4th magnitude Lambda Aquarii, and just below the point of a small triangle arrangement of 6th magnitude stars.

   This is a short video clip from a much longer video that I made as part of a live musical performance called “Orbit” at the Gottleib Planetarium in Kansas City Missouri during May 2011.

   
   
   

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