Sun Not in Aries But it is The March 2017 Equinox

   Monday March 20th is an equinox day. This means that for those in the northern hemisphere winter is ending and spring has ‘sprung’ (starts). For our counterparts south of the equator summer is ending and fall is beginning. From a geographical perspective we would describe the Sun as being over the Earth’s equator, and as this graphic shows there would be an equal amount of daylight and night on our planet as a result.
    At mid-day on the equator the sun is directly overhead and from that latitude you have no shadow, just a ‘blob-like’ shadow at your feet as this picture of my feet taken at mid-day in Quito Ecuador shows.

    Regardless of your hemispheric preference get outside and cast a shadow!

  Northern hemisphere spring officially (well at least astronomically) begins at 10:29 UT on the 20th (05:29 am CDT) when the Sun reaches the celestial coordinates of 0 hours and 0 degrees as it moves northward along the ecliptic crossing the celestial equator. At this location the Sun is within the constellation of Pisces the Fishes and not just entering Aries the Ram as the pseudoscience of astrology would have you believe.

    To learn more about the celestial coordinates click here to read a previous post about seasons and the equinox.

   Click here to see the online world sunlight map used to make the day/night graphic at the top of the page.

sun-earth   Click here to go to the NASA Sun-Earth Days web site.

   Here is a short series of hourly pictures taken during the day on the September equinox on the equator in Quito Ecuador at Collegio Menor San Francisco de Quito, a private school that I visited and did the SunShIP project with (Sun Shadow Investigation Project).

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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.

Sun Not in Pisces

The view from Earth - 18 February.

The view from Earth – 18 February.

  According to the pseudoscience of astrology the Sun enters the constellation of Pisces the Fishes on Saturday February 18th. In fact the actual position of the Sun is still within the boundary of the constellation of Aquarius the Water Bearer, as this graphic shows. The Sun had just entered Aquarius 2 days ago.

   Read a little more about how astrology has the Sun incorrectly placed in a previous blog, and in another blog discussing the effects of precession.
   
   
   
Caution: Objects viewed with an optical aid are further than they appear.
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Imbolog 2017

   Watch That WoodChuck!
groundhog newspaper   On February 2, we watch for the groundhog to emerge for reasons that originate from ancient Celtic tradition. Groundhog Day was known as lmbolog, or sheep’s milk, a time for nurturing young sheep and planting spring crops. The belief arose that if lmbolog were to be sunny and clear, then winter’s effects would endure, foreshadowing a long winter. How­ever, if skies were overcast, then the warmer days of spring would arrive early. To farmers then and today, an early spring means early spring plant­ing and a subsequent early harvest. Often fires were lit to commemorate the event as fires were a sign of warmth and light, both of which increased as days lengthened.
not a meteorologist   German immigrant farmers are credited with bringing Groundhog Day with them to the United States as they settled in Pennsylvania. To them, February 2 was called Candlemas Day, because of the practice of lighting candles on this day in celebration of early planting. The Germans believed that the badger was able to predict the weather on the basis of whether or not its shadow appeared. If the badger, or groundhog, saw its shadow on Candlemas, it would be scared and return to its burrow for another six weeks to sleep through the long winter. However, if the skies were cloudy then no shadows would appear, and an early and warm spring would be expected. The importance of this day to German immigrants, and its impact on their farming gave rise to the couplet:
         A farmer would rather see his wife upon a bier,
         than that Candlemas Day should be sunny and clear.

puxs-phil-lied   Year after year, since 1898, crowds have gathered in Punxsutawney, Pennsylvania, on February 2 to wait for a certain groundhog to emerge from its burrow. Today the belief in this as a predictor of weather is not nearly as consequential as it appears despite all the hoopla created by the news media. Yet, there is some scientific rationale to this ritual, albeit not in the accuracy of the forecast. When the skies are clear, temperatures tend to be cold as the ground radiates heat absorbed during the day back into the atmosphere; and when skies are over­cast temperatures tend to moderate as clouds trap heat nearer the ground.
Midpoints
Groundhog-Standing2   To other cultures in the Northern Hemisphere Candlemas Day was celebrated as the midpoint, or cross­ quarter day, between the winter solstice and the spring equinox. Cross-quarter days occur midway between the astronomical events that mark the beginning of each of the four seasons, the solstices and the equinoxes. The second cross-quarter day of the year, as it is calculated mathematically, occurs on May 6, although it is often associated with May Day, on May 1. The third cross­ quarter day of the year is August 7, the only one of the four without a significant event associated with it. Mid-autumn, the fourth cross-quarter day, occurs on the last day of October, Hallowmas Eve, or as we now know it, Halloween.
   Interestingly this system of equinox, solstice, and cross-quarter days has led to some confusion as to when the seasonal midpoints and endpoints occur. For example, June 21-22 is the official date for the start of summer in the Northern Hemisphere, but it is sometimes referred to as midsummer’s day. This would suggest that summer actually begins on May Day and ends in early August. In a similar manner, December 21, the start of winter for the Northern Hemisphere, is some­times referred to as midwinter’s day. This would imply winter actually begins at the end of October, and concludes (assuming no shadow is seen) on Groundhog Day.
groundhog   So will we have a long winter, or will it be short, and our spring be an early spring? No one can predict this, at least not based on seeing one’s shadow. However, come this February 2, rest assured that crowds will once again gather to watch Punxsutawney Phil emerge from his hole.
   Adapted from “Watch that Woodchuck” Scope on the Skies. Science Scope Magazine. February 1993.

   
   
   

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.

Sun Enters Capricorn and Aquarius

ww   Thursday January 19th at 14 UT the Sun in its apparent eastward motion along the ecliptic enters the boundaries of the constellation Capricorn the Sea Goat. This is the true or actual position of the Sun. However 7 hours later, at 21 UT, according to the pseudoscience of astrology, the Sun,will enter the constellation of Aquarius the Water Bearer.

   
   
   

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.

Earth at Perihelion 2017

Earth at Perihelion   Feel the Heat?
   Wednesday January 4th at 14 UT (8 am CST), as the Earth continues its annual trek around the Sun, the Earth reaches a point in its orbit that is called perihelion. Perihelion is the minimum distance that separates the Earth from the Sun, and we are the closest to the Sun for the year at this point in the orbit. So the Earth, this year, is 0.98330 AU (147,101,082 km; 91,404,374 miles) (compared with last year 2016: 0.98331 AU (147,099,586 km; 91,403,445 miles) from the Sun. Approximately one-half year or one-half revolution later, on July 3rd, the Earth is at aphelion and is 1.01668 AU(94,506,310 miles; 152,093,163 km), its maximum distance from the Sun for 2017. This difference in distances is due to the shape of the Earth’s orbit being elliptical rather than circular. However the Earth has a mildly elliptically shaped orbit that is closer to being slightly out-of-round than the incorrect, very elliptical orbit that is often shown – like the illustration used here.

sun2014-ani   In Astronomy the shape of a planet’s orbit is called eccentricity, with 0 being a circle and 1 a straight line. Any value between 0 and 1 represents an ellipse. The shape of the Earth’s orbit is so close to being circular that the apparent size of the Sun does not appear to change as this animated graphic shows. The difference between perihelion and aphelion is about 3%.

   Eccentricity for each planet is listed below for comparison.

Planet	   Eccentricity	
Mercury	   0.2056
Venus	   0.0068
Earth	   0.0167
Mars	   0.0934
Jupiter	   0.0484
Saturn	   0.0542
Uranus	   0.0472
Neptune	   0.0086
Pluto	   0.2488

   To read more about the Earth’s orbit and get some teaching ideas click here to download a PDF copy of my January 2011 Scope on the Skies column Solar Explorations.
   Here is a good classroom activity about the Earth’s orbit and its effect on the apparent size of the Sun: Why Does the Size of the Sun Appear to Change? A Year of the Sun.

   
   
   

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.

Sun Not in Capricornus but it is the 2016 December Solstice

sag-cap-ani    According to the pseudoscience of astrology the Sun enters the constellation of Capricornus the Sea Goat on Wednesday December 21st at 10:44 UT (04:44 am CST, when in fact the actual position of the Sun is still within the boundaries of the constellation of Sagittarius the Archer.
    In reality the Sun will have reached the celestial coordinates of 23.5o degrees south declination; 18 hours right ascension. With regard to the Earth’s surface this places the Sun over the Tropic of Capricorn, which is at 23.5o south latitude. We also know that it is the Earth’s tilt on its axis that is the cause for seasons on Earth rather than the distance between the Earth and the Sun. And of course we know that this signals the start of northern hemisphere winter and the southern hemisphere summer seasons.
earth-in-gemini    And for those ‘insanely curious’ like me, while the Sun is at 23.5o South declination and ‘in’ Sagittarius the Earth is opposite at 23.5o North declination and at the feet of the Gemini Twins.

   The animated graphic below sets the stage, so to speak, to illustrate the Sun’s actual location with respect to the zodiac constellations in the background. This is as opposed to the location of the Sun according to the pseudoscience of Astrology. The scene is set for 12:15 CST, or mid-day when the Sun is at an azimuth of 180o, or south, and is mid-way between rising and setting. Starting with the Sun at mid-day the scene changes as first the daytime sky is turned off, followed by the horizon being turned off.
   This leaves a sky view like during a total solar eclipse except that the Sun is not blocked out by the new Moon. And like during that solar eclipse the zodiac constellations in the background become visible. Then the following are added starting first with Sagittarius, then Capricorn, and then the ecliptic and celestial equator are added to show the relationship between the two constellations and what makes them plus another 11 constellations the astronomical zodiac of 13 constellations. The animation ends with the addition of the constellation boundary lines and labels for the rest of the constellations in this setting.
It is the ecliptic, the apparent path of the Sun which, if it crosses the boundary of a constellation, makes that constellation one of the zodiac. And during December the Sun’s apparent path takes it across the constellation of Sagittarius rather than Capricorn.

   Read a little more about how astrology has the Sun incorrectly placed in a previous blog, and in another blog discussing the effects of precession.
   
   
   

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.

2016: Sun Enters Ophiuchus

ophiuchus   Tuesday, November 29th the Sun in its apparent eastward motion along the ecliptic, moves out of the constellation Scorpius the Scorpion and into the constellation of Ophiuchus the Healer. This is the true or actual position of the Sun as opposed to the pseudoscience of astrology which usually has the astrological Sun one constellation ahead or east from the Astronomical Sun’s position.

ophiuchus-scorpion   Ophiuchus is the 13th constellation of the zodiac (Astronomical) but does not appear in the astrological zodiac nor in the astrology column found in many newspapers. A constellation of either zodiac is defined the same way using the ecliptic path. If the ecliptic passes through a constellation boundary then that constellation is a zodiac constellation. In the graphics I use the ecliptic path clearly crosses across the boundary for the constellation Ophiuchus the Healer.

   Ophiuchus is described in a mythology story as a healer. In one story following a mortal fight between Orion and Scorpius the Scorpion Ophiuchus kills the scorpion by stepping on it; extracts the venom from the scorpion; and then uses it to bring Orion back to life.
cadeuces   In Ophiuchus’s hands he is holding a long snake, the 2-part constellation of Serpens – Serpens Cauda (tail of the snake) and Serpens Caput (head of the snake). There are many stories about Ophiuchus and the snake including one where this is the origin of the symbol for medicine, the caduceus. However the caduceus is used primarily in the United States as the symbol for medicine, and is depicted as 2 snakes wrapped around a staff with wings. rodIf there is a connection with a medical symbol then it should be with the Rod of Asclepius, a staff with one snake.
   
   
   

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.