Mars at Eastern Quadrature

orbital-positions   Monday February 1st the position of the planet Mars, with respect to the Earth and the Sun, places this planet at what is called eastern quadrature. At that orbital position Mars, and actually any outer planet, is at a 90 degree angle from the Earth as this graphic shows, and the banner graphic at the top of the page shows. Think first quarter Moon as that is a fair comparison of the relative positions of Earth, Sun, and Mars.

   At this position Mars follows the Sun across the sky from east to west as the Earth is rotating, meaning that Mars rises after the Sun and then sets after the Sun. Mars, with an apparent magnitude of 0.45, is about 5o from the 5.8 magnitude Uranus.

   
   
   

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Leo, the Moon, Mars, Mercury, and a Ram

   No, that is not the opening line to a “walked into a bar…” joke, but rather an example of trying to fit 4 different topics into one title!
Read on.

   Friday evening January 29th the 17-day old waning gibbous Moon will be about 4-5o from the star Regulus. This star is known as the ‘Heart’ of the constellation Leo the Lion.

   Mars is visible further west over the southwest horizon and is a few degrees from the planet Uranus. Both are near the 3-star pattern for the constellation Aries the Ram and its brightest star Hamal with a 2.0 apparent magnitude. The two planets have a sharp contrast in relative apparent magnitude with Hamal and with each other – Mars at 0.40 and Uranus at a 5.80 apparent magnitude. Both planets will fit within the field of view of binoculars with Mars appearing as a small reddish ‘dot’ and Uranus, if seen at all, a much fainter bluish-green and smaller ‘dot’.

   Earlier in the evening, after sunset, look toward the western horizon for the innermost planet Mercury. With an apparent magnitude of 0.45 Mercury is slightly dimmer than Mars and should be easy to spot as it will be the brightest star-like object in that direction.

   
   
   

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The Twins Point the Way

   Wednesday evening January 27th the nearly full Moon, a 14-day old waxing gibbous Moon, will be about 6-7o from the star Pollux, one of the two twin stars of Gemini the Twins. The other ‘twin star’, the other brother, is Castor.

   Off to the west over the southern horizon are the planet Mars and Uranus. Further west is Neptune, and the Dwarf Planets Eris and Ceres. Earlier in the evening, after sunset local time the innermost planet Mercury is over the western horizon.

   
   
   

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Uranus at Eastern Quadrature – 2021

   Tuesday January 26th the position of the planet Uranus with respect to the Earth and the Sun places this ringed planet at what is called eastern quadrature. Uranus is at a 90 degree angle from the Earth. Think first quarter Moon as that is a fair comparison of the relative positions of the Earth, the Sun, and Uranus – or any outer planet. At this position Uranus follows the Sun across the sky from east to west as the Earth is rotating, meaning that Uranus rises after the Sun and sets after the Sun.

   So, where is Uranus? Look over the southern horizon after sunset for the reddish star-like object – the planet Mars. A few degrees above Mars is the star Hamal in the constellation of Aries the Ram. About 4o down to the right from Mars is the outer ringed planet Uranus.

   With a 5.77 apparent magnitude Uranus is just bright enough to be seen with binoculars as perhaps a very small dot. However Uranus is at about the naked-eye limit of visibility (6th magnitude) so it would take extremely dark skies to see it without optical assistance. Compare the apparent magnitude of Uranus with that of Mars at 0.34 and the 2.00 apparent magnitude for the star Hamal.

   
   
   

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January Moon at Ascending Node

   Sunday January 24th the 12-day old waxing 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 12-day old waxing gibbous Moon will be over the southeastern horizon around sunset local time. Mars is higher over the southern horizon while Mercury is low over the western horizon. In between are three outer planets, Uranus, Neptune, and Dwarf Planet Ceres.

   Uranus has an apparent magnitude of 5.8 and could be viewed with binoculars and certainly with larger aperture instruments and camera time exposures.

   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)
   
   
   
   
   
   
   

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Conjunction – Elongation – Conjunction

   Saturday evening watch for the 11-day old waxing gibbous Moon to be in conjunction with and about 3o from the reddish star Aldebaran in the constellation Taurus the Bull.

   Earlier in the evening the innermost planet Mercury was visible over the western horizon shortly after sunset. Mercury, on this date, will be at its Easternmost Elongation for this orbit. At elongation, eastern or western, Mercury, and also Venus, will be as far ‘out’ from the Sun to the right or left as we see the inner planets from Earth. At eastern elongation the inner planets follow the Sun across the sky during the day and appear as evening planets over the western horizon. At western elongation the inner planets ‘lead’ the Sun across the Sky during the day which means they rise ahead of the Sun and are seen as morning planets.

   But Wait – there’s still more!
   Saturn reaches solar conjunction on this date. During solar conjunction for an outer planet that outer planet will either be too close to the Sun to be seen or is on the opposite side of the Sun. When an outer planet reaches solar conjunction it moves from the evening skies to the morning skies.

   
   
   

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January Apogee Moon

   Our Moon reaches apogee, (furthest from Earth), for this orbit, on Thursday January 21st. For this apogee the 9-day old waxing gibbous Moon will be at a distance of 31.70 Earth diameters, 251,282 miles (404,400 km) from the Earth.

   On the date of the apogee, and high above the southwestern horizon, is the 8-day old waxing gibbous Moon. The Moon will be about 7o to the east from the planet Mars, and about 9o from the outer planet Uranus.


   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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Moon-Mars-Uranus Conjunction

   Wednesday evening January 20th the 8-day old first quarter Moon will be about 4o from the outer planet Uranus and about 6o from Mars. Over the next couple of days Mars and Uranus will be separated by about 1-2o as the faster moving Mars passes by Uranus.
   Earlier in the evening outer Planet Neptune and two Dwarf Planets, Eris and Ceres are also above the horizon. However with apparent magnitudes ranging from 8.0 to 19.0 none of these three would be visible without some sort of optical assistance,

   
   
   

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Sun Is in Capricornus not Aquarius


   Tuesday January 19th at 15 UT the Sun in its apparent eastward motion along the ecliptic enters the boundaries of the constellation Capricornus the Sea Goat. This is the actual location of the Sun.
   Interestingly, according to the pseudoscience of astrology, 6 hours later, at 21 UT Tuesday January 19th, the Sun should be entering the constellation of Aquarius the Water Bearer.

   
   
   

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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.

   
   
   

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