Moon – Mars/Neptune Conjunction

   Friday June 12th and Saturday June 13th before sunrise local time look toward the eastern horizon for the waning gibbous Moon to be near the planets Mars and Neptune. On both mornings the 20-22 day old Moon will be within about 7-9o from the two planets. Depending on your binoculars all three may fit within the field of view. However given the range of apparent magnitudes the reflected sunlight from Neptune (7.88) and possibly from Mars (-0.20) will be overshadowed by the much brighter Moon’s apparent magnitude (-12.0).


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Mars – Saturn Heliocentric Conjunction – 2020

   Monday June 1st two of the outer planets, Mars and Saturn, will be more or less at the same heliocentric longitude of about 280o, and would be in what is called a heliocentric conjunction. Heliocentric (Sun-centered) coordinates uses an overhead view of the solar system with planet location given as degrees of heliocentric longitude. The heliocentric longitude is based on a view from the Sun and is given as the angle between a planet and the vernal equinox. The vernal equinox, 0o, is located within the constellation of Pisces the Fishes, and is the intersection between the ecliptic and the celestial equator.
   As the Earth revolves around the Sun it ‘gives’ the Sun its apparent motion eastward along the ecliptic. When the Sun crosses the celestial equator at this intersection it is moving north. At the crossing northern hemisphere winter becomes spring – the opposite seasonal change for the southern hemisphere.

   Despite having the same heliocentric longitude, when viewed from the surface of the Earth, the two show an east to west difference of about 2 hours of right ascension.

   
   
   

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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Moon Mars Conjunction x2

   Thursday morning May 14th the last quarter Moon will be about 8-9o to the west from the ‘Red Planet’ Mars. The following morning, Friday May 15th the waning crescent Moon will be about 6-7o from Mars but this time on the east side.



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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Saturn at Western Quadrature – 2020

saturn-west-quadrature   Tuesday April 21st, the position of the planet Saturn with respect to the Earth and the Sun places this ringed planet at what is called western quadrature. Saturn 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 Saturn leads the Sun across the sky from east to west as the Earth is rotating, meaning that Saturn rises before the Sun and also sets before the Sun.

Saturn currently is within the constellation of Sagittarius the Archer as this graphic shows. From the northern hemisphere, looking toward the southern horizon, you can find Saturn over the southeastern horizon about midway between Mars to the east, left, and Jupiter to the west, right.

Learn a little (or a lot) about Saturn by visiting the Cassini at Saturn mission web site.
Click here to go to the Cassini Mission web site.

   This is a short 5 minute video I made as part of a live musical performance called “Orbit”. This is a piece from the much longer tour of the solar system performance and video and shows Saturn and some of its moons as viewed from the Cassini spacecraft that month.

   
   
   


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.

An ‘Old’ April Moon at Apogee

   Our Moon reaches apogee, (greatest distance from Earth), for this orbit, on Monday April 20th. At that time the new Moon will be at a distance of 31.86 Earth diameters 252,563 miles (406,641 km) from the Earth.

   On the day of the apogee Moon the 27.2-day old thin waning crescent Moon will be rising about 1 hour before the Sun rises and if spotted could become a personal record for seeing an ‘old’ Moon.

   While out looking for the Moon there are several planets arranged across the southern and southeastern horizon. They are arranged west to east (or east to west) along the ecliptic, the Earth’s orbital path around the Sun, as the two graphics below are showing.

   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” in NSTA’s Science Scope Magazine.

   
   
   
   
   
   
   
   
   

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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Morning Conjunctions

   This morning the 21-day old last quarter Moon was a few degrees from the outer planet Jupiter. As the Moon continues its eastward orbit, waning through the crescent phases, it will pass by Mars and Saturn, then 2 days later the waning crescent Moon will be close to the Dwarf Planet Ceres.



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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Planets on the Move

   Sometimes there are opportunities to observe the visible planets as they move along their respective orbital paths. Right now is one of those times when there are visible planets in both the evening and morning skies. And they are arranged such that you are able to see, not directly, but over a day at a time you are able to observe how planets closer to the Earth or Sun move relative to planets further away.
   The inner planet Venus, by itself in the evening skies, will pass across the stars of the Pleiades as this animated graphic shows. It is set at 1-day intervals and goes from April 2nd-5th.
   In the morning skies you will find three planets, Saturn, Mars, and Jupiter close together over the southeastern horizon before the Sun rises. Keep an eye on Mars as it moves past the slower moving Saturn.
   Shortly before sunrise the innermost planet, Mercury, rises and will also be visible as this graphic set for March 31st 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.


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Venus – Saturn Conjunction

   Wednesday evening November 11th look toward the western horizon for a grouping of 3 planets and one dwarf planet. Very low over the horizon and possibly to low to be seen is the outer planet Jupiter. About 7-8o east from Jupiter is the dwarf planet Ceres, however at nearly 9th magnitude and low above the horizon Ceres will be difficult to see, if at all.
   Several degrees east from Jupiter and Ceres is the brightly shining inner planet Venus and about 1-2o from Venus is the outer planet Saturn. These two planets will make a nice contrast in apparent magnitude (Venus: -3.95 Saturn: 0.57) as they easily will fit within the field of view of binoculars.

   
   
   

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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Thin Moon – 2 Days – 2 Conjunctions

   At around sunset Thursday November 28th look toward the western horizon for the 2.5-day old thin waxing crescent Moon to be close to the inner planet Venus, and an outer planet, Jupiter. The Moon will be about 1-2o from Venus and about 6o from Jupiter.
   Too dim to be seen with the naked eye at 8-9th magnitude and about 3o from the Moon is the Dwarf Planet Ceres.
   The planet Saturn is about 12o to the east from the Moon – which is where the Moon will be on the evening of November 29th. The two will be about 1-2o from one another.

   Both of these conjunctions between the Moon and planets are tight enough such that both groupings will easily fit within the field of view of binoculars.


   
   
   

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

   Our Moon reaches apogee, (greatest distance from Earth), for this orbit, on Thursday November 7th. At that time the Moon will be at a distance of 31.75 Earth diameters 251,693 miles (405,060 km) from the Earth.

   On the day of the apogee Moon the 11-day old waning gibbous Moon rises during mid-afternoon and sets later the following morning.

   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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