Jupiter Has 2 More

   Outer planet Jupiter has probably more moons than have been counted so far. The greater majority of these satellites of Jupiter orbit in retrograde relative to the rotation direction of the planet. Satellites of any planet that orbit their ‘parent’ planet in retrograde are called irregular satellites to distinguish them from satellites that formed with the planet, and consequently would orbit in the same direction as the planet’s rotation.
   Two recently discovered satellites, bringing the known or at least suspected number to 69, are described via their respective URL with a very official looking but somewhat confusing at first glance bulletin. The links are to the MPEC (Minor Planet Electronic Circular) at the Minor Planet Center.
   Both of these satellites were discovered or co-discovered by Astronomers Scott Sheppard, David Tholen, and Chadwick Trujillo. Given the small size and challenges in imaging these satellites it is amazing that they were discovered. Read more about the discoveries at Sky & Telescope‘s web site.

    MPEC 2017-L47 : S/2017 J 1 click here
    MPEC 2017-L08 : S/2016 J 1 click here

       Take a tour around Jupiter and its many satellites. The sizes of the Galilean satellites, Io, Europa, Ganymede, and Callisto have been made larger than they would actually be given the size Jupiter used in the 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.

Don’t Panic, It’s Only A Towel!


   Thursday May 25th, or any day that is May 25th we celebrate, in our own way, (yes we do) the Book,
Hitchhiker’s Guide to the Galaxy
, by Douglas Adams. What is the significance of the towel? Click on the graphic to enlarge it to a readable size to find out.
   So be a hoopy frood and click on this link to visit the Towel Day web site.

   Overheard on Jeopardy: “42.”
And the answer is: “What is the meaning of life?”
   
   
   

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.

Congress Downsizes the Solar System

   The US Congress today, in an effort to rectify the current sequestration budget cuts has made a dramatic announcement. In an effort to reduce the NASA budget, a resolution was passed today to downsize the solar system. According to an unnamed congressional staffer, House Republicans felt there has been “too much redundancy in the solar system” and that streamlining the 4.5 billion year old planetary system is long overdue. Such action would give NASA fewer places to go and this would allow the agency to carry out its space exploration goals within the funding profile that the House proposed earlier this summer.

   “Look, we have four terrestrial planets” said Congressman Rip U. Apart (R, OK), “and only one of them really works! So why not get rid of at least two of the others and clean up the neighborhood?” Most subcommittee members felt that while downsizing was definitely in the cards, eliminating both Mercury and Venus, or even Mars, was going too far. “We have too many international commitments to Mars.” said another politician. “So I think we should keep Mars and dump Venus and Mercury. It’s too hot to live on Venus, and liberal Democrats keep using it as an example of what climate change can do. So from a political and practical point of view, Venus has got to go.”

   Definitely at risk is the planet Mercury which lacks support because of its small size and poor visibility from Earth. “Who needs it?” asked Congressman Newt Onian (R, N.C.). “Have you ever seen it? I haven’t. So what good is it? We just don’t need useless planets. And speaking of useless planets, what about the asteroids? If you’ve seen one, you’ve seen them all. So I say we ought to get rid of the little boogers once and for all.”

   However, the downsizing recommendations do not stop with the terrestrial planets. The resolution also calls for a reduction in the number of gas giants which contain most of the planetary mass in the solar system. Most subcommittee members favor retaining Jupiter and Saturn, and eliminating Uranus and Neptune. “Jupiter employs the most molecules, and Saturn has those pretty little rings everyone likes.” said Rep. Con Mann (R, Fla.). “On the other hand, Uranus is a bore and its rings are dirty. And Neptune, for God’s sake, is just too far away.”

   The subcommittee was unanimous in its views towards Pluto which they deemed a moral misfit. “Now here’s a planet we can definitely do without.” continued Fornow. “Several years ago it was farthest from the sun (1979-1999), and now it’s not. It’s just too confusing. And now they tell me it’s really a Dwarf Planet. What the heck is going on here?”

   The resolution must now be presented to the entire House, where it is expected to pass easily since only a minority of Representatives have constituents on the affected planets. NASA Administrators have vowed to resist any further reductions to the solar system, saying that “NASA has expended considerable effort to make solar system exploration cheaper, faster, and better. Much of this work would be wasted if the solar system were downsized.”

   Critics say, however, that reducing the number of planets will not produce the expected savings to taxpayers. Textbooks, they note, would have to be revised to reflect the new arrangement, and facilities would need to be constructed to remove the planets themselves.

   April Fools!!

   
   
   

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.

A Martian ‘2fer’

   Saturday November 5th the planet Mars will be involved in two celestial events, however only one will be easily seen while the other would require a telescope or photo equipment.
   As this graphic shows the waxing crescent Moon will be within about 7o from the planet Mars – just a little too far for both to fit within the field of view of binoculars. That 7o is measured from my geographic location so depending on your location and viewing time Mars could be seen as being as close as around 5o from the Moon.
   Mars is also at heliocentric conjunction with the planet Neptune on November 5th. This is when two planets, other than Earth have the same heliocentric longitude. And on the 5th Mars and Neptune will share the same heliocentric longitude of 341.0o.
   Mars shines at an apparent magnitude of 0.41 while Neptune is considerably dimmer with an apparent magnitude of 7.8.

   
   
   

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.

2016 Mars Autumnal Equinox

   Monday July 4th is the autumnal equinox on the planet Mars as the planet transitions from summer during its 684 Earth day orbit around the Sun.
   Seasons on Mars are marked by the planet’s heliocentric longitude coordinates using the position of Mars along its orbit around the Sun. At the Martian spring equinox Mars is at 0o longitude.
   Each seasonal start/ending point is 90 degrees apart, but because of an elliptical-shaped orbit each Martian season is of varying lengths. Mars is at its greatest distance from the Sun, aphelion, before it reaches the Martian summer solstice when Mars is at 70o longitude. Perihelion, its closest to the Sun, is when Mars is at 250o longitude.
   Eccentricity of Mars and Earth for comparison.
Mars: 0.0934 – Earth: 0.0167

   I’m not exactly sure why this particular date is used but by international agreement astronomers have selected 11 April, 1955 as 0 degrees for year 1 of this Martian calendar. What this means is that Monday July 4th at 16 UT (11 am CDT) Earth time, is the start of autumn for Martian year 33 using the Earth-designed Martian calendar system.

   Mars is currently visible in the evening skies over the southern horizon after sunset local time.

Year 33
0 degrees — Spring Equinox — Jun 18 2015
90 degrees — Summer solstice — Jan 03 2016
180 degrees — Fall Equinox — Jul 04 2016
270 degrees — Winter Solstice — Nov 28 2016
Year 34
0 degrees — Spring Equinox — May 05 2017
90 degrees — Summer solstice — Nov 20 2017
180 degrees — Fall Equinox — May 22 2018
270 degrees — Winter Solstice — Oct 16 2018

Learn a little (or a lot) more about Mars at the NASA/JPL Mars Curiosity mission web site.

Here is approximately 3 minutes worth of Mars from the Orbit performance.

   
   
   

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.

A Tale of Two Junos

Juno #1:
   Tuesday April 26th asteroid 3 Juno will be at opposition, that is, it will be 180o from the Sun with the Earth between the two. At opposition, any Sun orbiting object beyond Earth rises at about local time for sunset and sets at local time for sunrise. At about 9th-10th magnitude the asteroid will be too faint to be seen with binoculars or the naked eye. There is, however, a much brighter asteroid shining at a about 5th magnitude, and a few degrees south from Jupiter. This is asteroid Hygiea, the 4th largest asteroid.
   Asteroid 3 Juno was the third asteroid discovered, hence its numerical prefaced name. It was discovered by German astronomer Karl L. Harding in 1804, and it is the 11th largest asteroid.
   Follow asteroid 3 Juno using the Heavens Above web site.

juno-jupiterJuno #2:
   NASA’s Juno mission to Jupiter is very near the end of its 5 year journey across the solar system. Launched in August of 2011 the solar powered spacecraft is expected to arrive at Jupiter on July 4th of this year. The Juno mission will place the spacecraft into a polar orbit that will consist of 30 orbits around the planet with each orbit lasting 11 days while Jupiter rotates below every 10 hours. After arrival the mission has a planned length of one year ending in October 2017 with the spacecraft de-orbiting and falling into the planet’s atmosphere.

   
   
   

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

NSTA @ Nashville


   I’m in Nashville Tennessee for the next several days at the NSTA national conference. Planets and stars will still be in the skies but not as easy to see from downtown Nashville as it is where I live. On the morning of April 1st the waning waning crescent Moon will be within a few degrees from Dwarf Planet Pluto. Too dim to be seen without a large telescope it is, nonetheless, a neat idea that when you look toward the Moon you are also looking in the direction of Pluto. It’s out there!
   And here is a sequence of graphics showing the pre-sunrise morning sky at 5:30 am EDT for each day during the conference, and one night view on April 1st showing Jupiter. Both Pluto and the Moon are located just above and to the left from the handle of the teapot asterism for Sagittarius the Archer.

   
   
   

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.