So you are interested in learning about the Summer Solstice or Winter Solstice? Stonehenge has a very important tie to the solstices in that it shows both the summer solstice sunrise and the winter solstice sunset.
Solstice comes from the Latin (sol, sun; sistit, stands). For several days before and after each solstice, the sun appears to stand still in the sky—that is, its noontime elevation does not seem to change.
Solstice derives from an ancient Latin word meaning "stop," or "to stand still."
According to Webster's New Collegiate Dictionary, it refers to one of two points when the sun is furthest from the celestial equator. In astronomy, either of the two points on the ecliptic that lie midway between the equinoxes (separated from them by an angular distance of 90 deg.).
At the solstices the sun's apparent position on the celestial sphere reaches its greatest distance above or below the celestial equator, about 23 1/2 deg. of arc. At the time of summer solstice, about June 22, the sun is directly overhead at noon at the Tropic of Cancer.
In the Northern Hemisphere the longest day and shortest night of the year occur on this date, marking the beginning of summer. At winter solstice, about December 22, the sun is overhead at noon at the Tropic of Capricorn; this marks the beginning of winter in the Northern Hemisphere. For several days before and after each solstice the sun appears to stand still in the sky, i.e., its noontime elevation does not seem to change from day to day.
With the warmth of the season caressing the land, the celebration of the Summer Solstice brings forth a truly joyous recognition that we can now enjoy the fruits of our labors in the past season. It is not surprising that this same spirit of pleasure and fun had carried over into our modern-day recognition of this, the longest day of the year.
Falling on June 21st or 22nd, the Summer Solstice is a time of light and of fire. It is a time to reflect upon the growth of the season: the seeds that were planted in the earth and the seeds planted in our souls. It is a time of cleansing and renewal. It is a time of love and growth as well.
The First Harvest - This is the time of the first harvest, which usually consisted of the herbs planted during the Vernal Equinox. Used for food, medicines and ritual, these gifts of the land clearly denote the importance of the harvest and the cycle of growth to the body, mind and soul.
Winter Solstice, or Yule, is held either December 21st or 22nd. It marks the shortest day of the year (in the Northern Hemisphere) and is an important holiday to those who follow the old ways.
To the ancients, it appeared as if the Sun and Moon stopped in their flight across the sky - this is the longest night of the year and was a time of both anticipation and rejoicing at the Sun's rebirth out of the Goddess.
The Sun's representation as the male divinity, or celestial ruler, predates Christianity. As with other rituals and celebrations, the Church felt that by assimilating this holiday into the Christian beliefs, it would help convert those who still followed the Old Way.
The reason for the different seasons at opposite times of the year in the two hemispheres is that while the earth rotates about the sun, it also spins on its axis, which is tilted some 23.5 degrees towards the plane of its rotation. Because of this tilt, the Northern Hemisphere receives less direct sunlight (creating winter) while the Southern Hemisphere receives more direct sunlight (creating summer). As the Earth continues its orbit the hemisphere that is angled closest to the sun changes and the seasons are reversed.
When watching a solstice you need to be very careful you do not hurt your eyes. Obviously the sun is not as bright as if you were looking at an eclipse but no matter what you need to be careful. Your first concern when looking anywhere near the sun should always be eye safety. Serious eye damage can result from even a brief glimpse of our sun. Don't just assume you can go out and purchase glasses for solstice viewing or some other type of solstice eyewear. You may view the Sun directly only through a special filter made for safe solar viewing. There are no specific glasses for solstice viewing but here is a great site about sun viewing safety.