Inner Meets Outers – In A Triple Conjunction

   Sunday morning February 28th the innermost planet, Mercury, and two of the ringed outer planets, Jupiter and Saturn, will be in a triple conjunction as Mercury moves eastward past Saturn and then Jupiter. Mercury will be about 3-4o from Saturn and about 2-3o from Jupiter.
   All three will almost fit within the field of view of binoculars and should make for an interesting contrast in apparent magnitudes however Jupiter (-1.97) far outshines Mercury (0.30) and Saturn (0.71).

   
   
   

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.

Mercury – Saturn – Jupiter Together Again!

   Saturday morning February 20th in the hour or so before the Sun rises look for the innermost planet Mercury to be about 4-5o from Saturn and Jupiter. All three should fit within the field of view of binoculars, but the three planets will be low above the horizon.

   
   
   

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.

Eppur Si Muove


   February 15th is Galileo Day.
   Quoting Galileo, “and yet it still moves”, in reference to the Earth actually orbiting the Sun. So how to acknowledge his achievements and contributions to modern Science? Read on…

   Jupiter’s Moons
   One enjoyable pasttime is to observe the constantly changing four largest moons orbiting Jupiter. Sometimes known as the Galilean Satellites, they are: Io, Europa, Ganymede, and Callisto. Named after Galileo who made many observations of the moons and from these observations and other observations led him to question the Geocentric model of the solar system. These four planet-sized moons are visible as small bright stars on either side of Jupiter and depending on the time and date of viewing their arrangement around Jupiter is never the same as this animated graphic, set to 1-Earth day intervals, is showing.
   Recreate Galileo’s observations of the Galilean satellites through the use of an online simulation, the Java applet, Juplet. Input dates or times to see the position of the four Galilean satellites.
The Juplet will display the planet and the satellite configuration for the date and time on the computer, or you could easily edit the date and time, and after pressing the Enter key see a different configuration. To keep track of these changes the position of each satellite relative to Jupiter could be drawn on a data table similar to Galileo’s data table.

   This video, ‘Orbs of Jupiter’, was one of the videos I made for a live musical performance at the Gottleib Planetarium at Science City in Kansas City MO. The original videos were made for full-dome projection – this one has been flattened. Music was written by Richard Johnson and performed by Rebecca Ashe (Flute) and Cheryl Melfi (Clarinet). Live and pre-recorded Electro-acoustical sampling by Richard Johnson and Daniel Eichenbaum. The soundtrack for the video is from the live performance by Dark Matter.

   
   
   

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.


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Waxing Crescent Moon – Mercury Conjunction

   Did you miss the 27-day old thin waning crescent Moon conjunction with Venus this past Monday morning? I did!
   Well there is an opportunity to see the thin crescent Moon on this side of new phase this Thursday evening January 14th. The 1.7-day young waxing crescent Moon will be over the western horizon in a line-up of sorts with Mercury, Jupiter, and Saturn all angled downward toward the western horizon. From Saturn to the Moon will span about 13o with Mercury, about 3-4o to the west, (down to the right) being the closest of the 3 planets.

   This animated graphic is set for 2-minute intervals starting at 5:30 pm CST.

   
   
   

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.


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Morning and Evening Conjunctions

   Monday morning and evening, January 11th, offer an opportunity for catching a pair of conjunctions. Low over the eastern horizon at sunrise is the 27.7-day old very thin waning crescent Moon about 3-4o from the inner planet Venus.

   This could be a chance to see the Moon when it is about 24-hours from its new phase.

   Low in the western horizon at sunset is the ongoing triple conjunction between Mercury, Jupiter, and Saturn. Monday evening will be the closest Mercury and Jupiter will be as Mercury continues moving eastward away from the two giant planets.

   
   
   
   
   
   
   
   
   

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.


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Grand Conjunction Part 2: A Triple Conjunction!

   Just when you thought it was over, it is not! Yes Jupiter and Saturn are certainly low over the western horizon and both are setting closer to sunset, however…
   The innermost planet Mercury will be passing by Saturn then Jupiter over the next several evenings (January 7th to 12th) in a series of conjunctions as the graphics below are showing.
   Each of the conjunctions brings the three planets all within the field of view of binoculars and should make for an interesting contrast in apparent magnitudes. Jupiter: -1.94; Saturn: 0.60; Mercury: 0.89.

   
   
            Be careful observing because the Sun is close.

   
   
   

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.


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New Year’s Eve 2020

   The evening skies of this year’s New Year’s Eve begins at sunset with two of the giant planets, Jupiter and Saturn, low over the western horizon at sunset, but still within about 1o from each other. Higher over the southern horizon is the planet Mars. And with optical assistance or a camera the other two gas giant planets, Uranus and Neptune, as well as Dwarf Planet Ceres could be seen.

   Later, at around midnight and centered over the southern horizon will be the ‘regular’ Northern Hemisphere winter display of stars. This is a familiar groups of bright stars in a rough circle around the constellation of Orion the Hunter, and sometimes referred to as the “Winter Hexagon” or ‘Winter Circle”.

   As the winter hexagon the member stars are Rigel in Orion the Hunter, Aldebaran in Taurus the Bull, Capella in Auriga the Charioteer, Pollux and Castor in the Gemini Twins, Procyon in Canis Minor, and Sirius in Canis Major.


   
   
   
   We’ve survived another orbit.
   
   
          Happy New Year!
   
   
   
   
   
   
   
   
   

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.


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December Moon at Apogee

   Our Moon reaches apogee, (furthest from Earth), for this orbit, on Thursday December 24th. For this apogee the 10-day old waxing gibbous Moon will be at a distance of 31.75 Earth diameters, 251,662 miles (405,011 km) from the Earth.

click on graphic to see it larger   On the date of the apogee, and high above the southern horizon, is the 10-day old waxing gibbous Moon. The Moon will be about 13o to the east from the planet Mars, and about 2-3o from the outer planet Uranus. Jupiter and Saturn, still close together, are low over the southwestern horizon.


   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 Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)

   
   
   
   

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.


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How Close is Close?

   There has been a lot of discussion about what the Grand Conjunction between Jupiter and Saturn will look like to the unaided eye. The separation will be as close as 1/5th the width of the full Moon, which is hard to visualize. Astronomically, using angular angle measurements of degrees, minutes, and seconds, the separation will be 10.0′ (10 minutes). The full Moon, for comparison, is approximately 0.50o , or one-half of a degree.

   Still hard to visualize? Hold a quarter or a nickel at arms length and look at the edge of the coin. The width of the coin’s edge at arm’s length is approximately the separation between Jupiter and Saturn on the 21st.

   Still trying to visualize the 0.10′ separation? From whenever the old days were, there was a test of visual acuity (eyesight!) that involved being able to see the double star in the bend of the handle of the Big Dipper. There are actually 3 stars there but Mizar and Alcor are the two that are more easily seen. So, if you are able to see Mizar and Alcor then you should be able to see the separation between Jupiter and Saturn.

   
   
   

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.


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Crescent Moon – Jupiter/Saturn Conjunctions


   As we are getting ready for the Grand Conjunction on the 21st the Moon reappears in the evening skies and waxes its way past Jupiter and Saturn on Wednesday the 16th and Thursday the 17th.


   The three set around 1-2 hours after local time for sunset, and all will fit within the field of view of 7×50 binoculars as the graphic is showing.

   
   
   
   
   
   
   
   
   

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.


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