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.

Juno at Jupiter-Update

   The Juno Spacecraft is now fully engaged in making its planned orbits around the outer planet Jupiter. Since arriving and orbital insertion the spacecraft has made 6 orbits around Jupiter sending back amazing images and advancing our knowledge of the planet and its role in the solar system.
   Showing my age but I can remember how excited I was during the Voyager 1 and 2 flybys of the outer planets Jupiter, Saturn, Uranus, and Neptune during the 1980s. It was 40 years ago, Voyager 1 September 5th1977 – Voyager 2 August 20th 1977, when the spacecraft were launched. While both were targeted for a Jupiter and Saturn flyby Voyager 2 eventually had its mission rearranged so that it would fly past all four of the outer giant planets in a mission called the ‘Grand Slam’ or ‘Grand Tour’. The images from those flybys were just as exciting as the images we see from the current Juno mission albeit improved after 40 years of imaging technology advances.
   So Where are the two Voyagers now? Click here to find out.
   Click here to go to the NASA Video web site to see a short video (15 minutes) about the Voyager mission to the outer planets. This is part of a video series I often used in my Planetarium and classroom during the 1990s – so please realize that the graphics and animations, as well as some descriptions and some explanations are not necessarily as ‘advanced’ as things are now. However two of my heroes, Dr. Edward Stone, and Dr. Andrew Ingersoll, are featured making comments about some of the Science and discoveries.
   Below is a well done video compilation of images taken by the Juno Spacecraft. Click here to go to the Vimeo web site for the original video.

   
   
   

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.

July Moon at Descending Node

   Wednesday July 12th the 18-day old 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 18-day old waning gibbous Moon will be over the south-southeast horizon an hour or so after sunset local time. 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.

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.

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.

Neptune at Solar Conjunction

view-from-earth_neptune-solar-conjunction   Thursday March 2nd the outer planet Neptune reaches a point in its orbit where it passes behind the Sun as we view this from Earth. Neptune, and the other outer planets, dwarf planets, or small solar system bodies, all eventually reach this position on the opposite side of the Sun known as solar conjunction.

   
   
   
   
   
Caution: Objects viewed with an optical aid are further than they appear.
Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Moon Moons Uranus

   Thursday January 5th the just past first quarter Moon, a waxing gibbous Moon, is close to the outer planet Uranus, and also two of the Dwarf Planets. But close only in the sense that the three are in the same direction, or line of sight. Uranus as the next-to-last outermost of the 8 planets is 19.8 Au and has an apparent magnitude of 5.8. Ceres and Eris, while both are Dwarf Planets, are at very nearly the opposite ends of the solar system. Ceres is within the asteroid belts at a distance of 2.5 AU and has an apparent magnitude of 7.64. Eris, on the other hand is 96 AU from the Earth and has an apparent magnitude of 18.6.

   
   
   

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.