August Moon at Perigee

   Our Moon reaches perigee, (closest distance to Earth), for this orbit, on Friday August 2nd. At that time the Moon will be at a distance of 28.175 Earth diameters, 223,319 miles (359,398 km) from the Earth.

   On the day of the perigee Moon the 2-day old thin waxing crescent Moon will be over the western horizon setting about 1 hour after the Sun sets.

   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)

   Read this very informative article about the Earth-Moon system and their orbital motions, written by Joe Hanson. “Do We Orbit the Moon?”

   
   
   

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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Dwarf Planet Ceres at Opposition

   Tuesday May 28th Dwarf Planet Ceres reaches solar opposition – on the opposite side of the Sun as (not) seen from Earth.
   Dwarf Planet Ceres, formerly classified as an asteroid, is the largest member of the inner asteroid belt. Read and learn more about the closest Dwarf Planet to Earth.
   
   
   
   
   

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 Crescent Moon – Venus Conjunction

   Wednesday and Thursday mornings, May 1st and 2nd the 26 to 27-day old thin waning crescent Moon will pass by the inner planet Venus coming the closest on the 27th when the two will be separated by about 3-4o. A day later, Friday, the very thin waning crescent Moon will be near Mercury and the outer planet Uranus, but the Sun will be less than 45 minutes behind them – meaning the sky may be too bright to see the Moon or Mercury.
   Further to the west the outer planets Saturn and Jupiter are visible in the area around Sagittarius and Scorpius. Even a bit further west is the closest Dwarf Planet to the Earth, former asteroid 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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The Moon and a Dwarf Planet

   Monday morning April 22nd, before the Sun rises, look toward the south-southwest for the 17-day old waning gibbous Moon. While the Moon is obviously easy to see at a -12.60 apparent magnitude, the nearby, (2-3o), dwarf planet Ceres with an apparent magnitude of 6.90 is outshined by the Moon and is not visible.
   As this graphic shows all of the naked-eye visible planets except Mars are arranged from west to east above the horizon. While not naked eye visible Neptune, with an apparent magnitude of 7.94, is also shown. This arrangement of planets then offers an opportunity to visualize the plane of the ecliptic, the Earth’s orbit extended onto the sky. The plane of the ecliptic is one of the primary frames of reference for our solar system, and one of the things the other 7 planets have in common is that their respective orbits are all within about 7o from the plane of the ecliptic. Even our Moon stays within about 6o from the ecliptic.
   
   
   

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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March Moon at Apogee

   Our Moon reaches apogee, (greatest distance from Earth), on Monday March 4th. At that time the Moon will more or less be at a distance of 31.86 Earth diameters 252,520 miles (406,391 km) from the Earth.

   Does our Moon actually go around the Earth? 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*

   On the day of the apogee the 27.5-day old very thin waning crescent Moon will be over the southeastern horizon 30-60 minutes before sunrise local time.

*Click here to read my 2006 Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)

Read this very informative article about the Earth-Moon system and their orbital motions, written by Joe Hanson. “Do We Orbit the Moon?”

   
   
   

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 Conjunction with Dwarf Planet Ceres, then the Next Day with Jupiter

   In the hour or so before the Sun rises on the morning of February 26th look for the 21-day old last quarter Moon to be about 3-4o from the Dwarf Planet Ceres. Realize, however, that seeing Ceres is not really possible given that Ceres has an apparent magnitude of between 7th to 8th, while the last Quarter Moon has an apparent magnitude between -11th to -12th.
   In any case, on the morning of the 27th look for the 22-day old waning crescent Moon to be about 1-2o from the outer planet Jupiter.


   
   
   

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 and Jupiter in Motion

   If the morning skies are clear and the temperature is tolerable go out before sunrise local time and look toward the east. The two brightest stellar objects are the planets Venus (brightest) and Jupiter. A few degrees from Jupiter is the reddish star Antares in Scorpius the Scorpion. Dwarf Planet Ceres is also in this part of the sky but it is too dim to be seen with the unaided eye. As the graphic shows this is also near the Milky Way but seeing that would require much darker skies than many of us live under.

   Both planets are in motion as they orbit the Sun following their respective orbital path. As an inner planet and much closer to the Sun Venus moves more quickly than Jupiter so as days pass Venus will noticeable move more so than Jupiter. Venus was at its western elongation last month and now Venus is in the part of its orbit where it is moving eastward toward the Sun. As Venus moves in that direction Venus will catch up to and then pass Jupiter, coming the closest on January 23rd.
   The animated graphic is set for 1-day intervals from January 15th to January 31st.
   For comparison Venus moves 1.6o each day while Jupiter moves 0.083o each day. The Earth is also in motion and moves about 1.0o each day. So as the Earth moves the sky appears to move toward the west and as this happens Saturn comes into view toward the end of January. The waning crescent Moon shows up also at the end of the 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.


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