Inner Planets on the Move

   This past month, November, the inner planets Mercury and Venus were very visible in the early morning skies before sunrise. Both of the planets were at or near their respective western elongation. Venus was there during August and Mercury reached its western elongation on November 10th.
   What I wanted to capture was the daily change in the position of Venus as it passed the star Spica in Virgo the Harvest Maiden. Venus moves about 1.6o each day so its eastward motion should be obvious after a day or so. It was – it is!. Mercury, if you are wondering, moves about 4o each day.
   Both inner planets were somewhere around their maximum separation from the Sun – as we see it the inner planet is to the right side of the Sun, or toward the west.
   The series of pictures were taken from two locations near my house. One is from an empty lot near U.S. Highway 50 looking east. The other pictures are from somewhere along the street I live on! The first picture was taken at Legacy Park and includes the ISS orbiting over my location.


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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A Snake, Bird, and a Cup

Click on this graphic to see it animated

Click on this graphic to see it animated

   Above the southern horizon during the northern hemisphere mid-winter pre-dawn hours is an interesting grouping of four constellations of which three are centuries old classical constellations linked together in mythologies, while the fourth constellation, Sextans the sextant, is a ‘modern’ constellation.
   As perhaps the longest constellation the stars of Hydra the Watersnake, known in mythology as the many-headed snake that Hercules battled, meanders across the sky from east to west.
   According to mythology the constellation’s great length represents the long time it took for Hercules to defeat Hydra. Hydra had nine heads, and as Hercules found out, simply cutting off each of its heads was not sufficient to slay the snake. For as soon as one head was cut off, two more would grow back in its place. So, in order to defeat Hydra, Hercules had to burn each decapitated stump. The Sun’s progression in the skies down the length of the constellation Hydra represents Hercules’ progress in killing the snake.
   During northern hemisphere summer, the Sun is in Cancer the Crab as Hydra’s head rises in the East. Both Leo and Virgo stretch end to end, parallel to the snake’s body. So as the Earth revolves around the Sun, the Sun appears to move from Cancer eastward into Leo, and then into Virgo. Throughout this period, the Sun’s light drowns out more and more of the stars in Hydra and the ‘fire’ from the Sun sears the stumps as Hercules continues to successfully cut off additional heads.
corvus-crater   Riding on the back of Hydra are two inconspicuous constellations, Corvus the Crow and Crater the Cup . These two constellations have been associated with the god Apollo. Crater has been known as Apollo’s goblet, and Corvus has been known as the bird of Apollo that sometimes performed special deeds for him.
Click here to go to the Qué tal in the Current Skies web site for more observing information.

Follow the Arc

The ‘Evening Arc’

   There is an ‘old’ Astronomical saying, a sort of memory aid, for finding at least two constellations by way of their alpha, or brightest star in their respective constellation. In Bootes the Herdsman there is the orange-reddish star Arcturus, and in Virgo the Harvest Maiden the bluish-white star Spica. The saying – “follow the arc to Arcturus, then speed to Spica” is how you connect these two stars with the curve, or arc, in the handle of the Big Dipper. Simply look toward the north to find the 7 stars making up the Big Dipper, look for the curved handle and follow the arc or curve toward Arcturus and then continue on to Spica. This is typically done during the Northern Hemisphere spring and summer season when Bootes and Virgo are in the evening skies. However you can start this observation at sunset by looking northwest for the Big Dipper and then toward the southwest for the star Arcturus. Do this early enough as Arcturus sets about an hour after sunset and in the next couple of weeks Arcturus will become too close to the Sun and will not be visible again until later during the winter as a morning visible star.

The ‘Morning arc’

   And you could continue this observation the following morning as this part of the sky rises before the Sun and you trace out the arc passing through Arcturus and ending at Spica. As the ‘Morning Arc’ graphic shows the planet Venus is close to Spica.
   Keep an eye on this part of the sky as later this month the planets Saturn and Mercury start becoming visible before sunrise. On the 26th Venus will be very close to Saturn. As the graphic shows the two planets will be close enough for both to fit within the field of view of binoculars.

Click here to go to the Qué tal in the Current Skies web site for more observing information.