The Solstice

Each year the sun passes the summer solstice and the winter solstice.  These points define the first days of summer and winter respectively. 

Part 1 - Give the astronomical coordinates (Right Ascension & Declination) of these two points (very easy). 

Summer Solstice  RA = 6 h   Dec = +23½             Winter Solstice   RA = 18 h  Dec = -23½

Part 2 - Will these values change if you take into account precession?   That is, if you wait, say, 6000 years will your answer be different?  Explain.

These coordinates will NOT change over time.  What will change (due to precession) will be which constellation the winter & summer solstices will appear in.  Right now, the summer solstice appears in the constellation Gemini but in the distant past, it appeared in the constellation Cancer.  As the earth wobbles on its axis, the Vernal Equinox migrates slowly westward along the ecliptic but it will still act as the origin ( RA = 0  Dec = 0).   The solstices simply move westward at the same pace.  Therefore, the coordinates of the summer solstice will always be RA = 6 h   Dec = +23½    (OK, that is still a bit of a lie ... and if you say why I will be really impressed.  You see, there are slight changes to the tilt of our axis ... so the declination will be close to +23½ but it does vary a bit.  I don't expect you to know that.)

Due to precession, the entire grid system shifts in time against the background stars but the vernal equinox will always be the origin (0,0)

Part 3 - The word solstice comes from the phrase "sun stands still".   With the correct reference this phrase makes perfect sense.  That is, what about the sun is not changing around the solstices?  Explain in your own words.

First think about a pendulum swinging back and forth.  At what point in the swing does it seem to stop?  At both ends of the swing, of course.  The sun does the same thing as it goes through its yearly north-south trek.   If you look carefully at your sky chart you will notice that the sun makes very little north/south (up/down) changes in the sky around the time of the solstice.  Astronomers would watch the sun migrate progressively higher in the sky (at noon) around late March.  Likewise, in late September the sun appears lower and lower in the sky each day (at noon).  This is not the case during the solstice.  It is almost like the sun stands still during these times.  That is, the sun remains very high in the sky for a very long time (at noon) around June 20th.

I will also accept any answer that explains that the days near the solstice are all very similar in the following respects:  time of sunrise/sunset, daily path of sun across the sky, duration of sunlight.  You see, as you approach a solstice these aspects of the day change very little.  In fact, there is about a two week period (one week on either side of the solstice itself) where all the days stay (pretty much) the same.  This effect, however, is dependant on your latitude.  The further you are from the equator, the more dramatic the observation

For example: In Milwaukee near the solstice the duration of daily sunlight varies by about one minute over a two week span.  However, closer to the equinox, the length of a daylight changes about 3 minutes from one day to the next.

Part 4 - The four cardinal points all have astronomical symbols:  For example, the Vernal Equinox looks like this:

It is suppose to resemble a rams head since it once was called the "first point of Aries" ... for the ram (that is a bit of a hint).  Your job is to provide me with the astronomical symbol for each solstice and a logical explanation why this would be so.  Hint:  If this helps, the symbol for the Autumnal Equinox looks like the:

You needed to think about which Zodiac constellation these cardinal points were in the distant past rather than where they appear now (due to precession).  That is, the vernal equinox was once in Aries (but is now in Pisces).

The symbol for the Autumnal Equinox is also the symbol for Libra.  If you realized that, you may have noticed that Aries and Libra are opposite of each other in the Zodiac.  It stands to reason that the symbol for each Solstice are 3 Zodiac constellations away from each Equinox (there are a total of 12 constellations in the Zodiac).   Therefore, the symbols for the summer solstice should be Cancer and the symbol for the winter solstice is Capricorn.

      Cancer = Summer Solstice                                                      Capricorn = Winter Solstice