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.

   
   
   

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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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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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Waning Gibbous Moon and the Twins

   Thursday evening December 3rd the 20-day old waning gibbous Moon will be in the arms of the Gemini Twins. Look for the Moon, Pollux and Castor as they rise a couple of hours after sunset local time.

   
   
   

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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Mars at Ascending Node

click on graphic to see it larger   Two or three times each month I post information about the location of our Moon as it crosses the ecliptic, the Earth’s orbital path around the Sun. These are known as nodes and there is an ascending node and a descending node representing the location where the Moon crosses the ecliptic moving north or south.

   The ecliptic is used as the reference for all solar orbiting objects and with regard to the planets each of them is tilted or inclined from the ecliptic. So each planet, like our Moon, has an ascending and descending node.

   On Wednesday December 2nd the planet Mars crosses the ecliptic moving north, it’s ascending node.

   Click here to learn a little more about the ecliptic. This was a previous post from December 2019, but it still illustrates the ecliptic and the planets respective orbits relative to the ecliptic.

   This table shows the inclination of planets relative to the ecliptic as well as the Sun’s equator extended outward.

   
   
   
   
   
   
   

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 Ascending Node

   Tuesday December 1st the 17-day old waning gibbous Moon will be crossing the plane of the ecliptic moving north. 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 the day of the node crossing the 17-day old waning gibbous Moon will be over the eastern horizon around sunset local time. Mars is higher over the southeastern horizon while Jupiter and Saturn are low over the western horizon.

   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 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 return to bobs-spaces.


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November Moon at Apogee – And the Ecliptic

click on graphic to see it larger   Our Moon reaches apogee, (furthest from Earth), for this orbit, on Thursday November 26th. For this apogee the 12-day old waxing gibbous Moon will be at a distance of 31.82 Earth diameters, 252,211 miles (405,894 km) from the Earth.

   On the date of the apogee the 12-day old waxing gibbous Moon will be about 12o to the east from the planet Mars. The Moon will also be about 11o west from the outer planet Uranus. Currently Uranus has an apparent magnitude of around 5.7 meaning that it could be seen with the unaided in dark enough skies, or with telescopes and even binoculars – as long as the Moon is not in that part of the sky.

   Along the Ecliptic
   You may notice the arrangement of the planets spread across the horizon as shown in the graphic. Many objects in our solar system orbit the Sun in a path that is somewhat parallel with the Earth’s orbit, the ecliptic. All of the orbits are tilted or inclined away from the ecliptic however the 8 classical planets all have orbits that are inclined less than 7o from the ecliptic. Dwarf planets, asteroids, comets, for example, have orbital inclinations greater than 7o.
   The ecliptic also defines the Sun’s apparent path against the background of stars throughout the year. The planets are also in motion as they orbit the Sun as the video below illustrates.
   Take a short cruise along the ecliptic with the Sun!


   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)
   
   
   
   

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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Waxing Gibbous Moon – Mars Conjunction


   Wednesday evening November 25th the 11-day old waxing gibbous Moon will be about 3-4o from the planet Mars.

   
   
   

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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