Stretching the Sunlight

lion2lamb   The skies of March reflect the transition from winter to spring in the northern hemisphere, and is also the time when some say that “spring comes in like a lion and goes out lamb”. This has to do with the placement of the constellations Leo the Lion and Aries the Ram (not a lamb), as this graphic below is showing.
   This time change coincides with the season change and is seen in the sky with Leo rising in the east while Aries sets in the west. Between these two are the easily recognized stars belonging to Taurus the Bull, Orion the Hunter,and others that are associated with northern hemisphere winter night skies.
springforward   Time also shifts as we gradually transit seasons. The United States as well as other countries will make the shift from Local Standard Time to Daylight Saving Time on Sunday March 8th by setting clocks forward one hour. Hence we “spring forward” one hour.
   This adjustment was first proposed by an Englishman, William Willett, in his pamphlet Waste of Daylight, published in 1907. It took nearly ten years for the idea to catch on before it was passed into law by the United States Congress as the Standard Time Act in 1917. The entire country, U.S.A., was placed under Daylight Saving Time starting on March 30, 1918. This occurred during our involvement in World War I and the act was adopted in part to help the war effort by increasing the number of usable daylight hours and saving energy. At the close of the war, the act was repealed and was not reinstated on a permanent basis until the start of World War II.
   Over the years, the dates for the two time shifts has fluctuated but now due to the Energy Policy Act of 2005 Daylight Saving Time, in the U.S.A., begins on the first Sunday in March and ends with the return to Standard Time on the first Sunday in November.

   It is Saving time, not Savings Time. Savings are what you do with money in a bank.

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.

It’s the Time of the Season

A Martian Year

A Martian Year – at One Earth Month Intervals

   Today is the northern hemisphere spring equinox on the planet Mars as the planet transitions from winter to spring during its 684 Earth day orbit around the Sun. Seasons on Mars are marked by the planet’s heliocentric longitude coordinates using the position of Mars along its orbit around the Sun. Each seasonal start/ending point is 90 degrees apart, but because of its elliptical-shaped orbit each Martian season is of varying lengths. At the Martian spring equinox Mars is at 0 degrees longitude.
   I’m not exactly sure why this particular date is used but by international agreement astronomers have selected 11 April, 1955 as 0 degrees for year 1 of this Martian calendar. What this means is that today, 31 July Earth time, is the start of a ‘new year’, the first day of spring for year 32 using the aforementioned calendar system.

Year 32
0 degrees — Spring Equinox — Jul 31 2013
90 degrees — Summer solstice — Feb 15 2014
180 degrees — Fall Equinox — Aug 17 2014
270 degrees — Winter Solstice — Jan 11 2015
Year 33
0 degrees — Spring Equinox — Jun 18 2015

Learn a little (or a lot) more about Mars at the NASA/JPL Mars Curiosity mission web site.

Here is approximately 3 minutes worth of Mars from the Orbit performance.

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

June Solstice

Sun's Apparent Motion Along the Ecliptic

Sun’s Apparent Motion Along the Ecliptic – from Taurus to Gemini

   Northern hemisphere spring comes to an end and its summer begins at 12:04 am CDT (05:04 UT) on 21 June as the Sun ‘reaches’ the celestial coordinates of 23.5oN and 6 hours right ascension. With respect to the Earth’s surface the Sun is described as over the Tropic of Cancer, 23.5oN of the Earth’s equator. At this same time the Sun is still within the boundaries of the constellation Taurus the Bull – but just barely. Interestingly 9 hours later, (9:00 am CDT – 14 UT), the Sun ‘will move’ into the region of Gemini as it crosses the boundary between Gemini and Taurus.
   We know that it is the Earth’s orbital motion around the Sun giving rise to the sun’s apparent eastward motion amongst the stars in the background. This is how the Sun ‘reaches’ a celestial coordinate, how it ‘crosses’ the boundaries between constellations, or how it is ‘in‘ a constellation.
   With respect to the southern hemisphere this is the end of their summer and start of their fall season so thinking globally my preference has been to use the name of the month to designate the season change. Hence the use of the term June Solstice rather than the limited to northern hemisphere term summer solstice.

   Follow the seasons by observing how vegetation changes during 1 year. The video below was produced by an Earth orbiting satellite operated by the NASA/NOAA Suomi National Polar Orbiting Partnership (NPP). It is a really interesting narrated tour of the Earth from orbit over a variety of geographic features and landscapes.

Just had to include this!!

Just had to include this!!


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

March 2013 Equinox

   Today is an equinox day meaning that for us in the northern hemisphere winter is ending and spring has sprung. 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 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 begins at 6:02 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. 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 above.

   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 more observing information.