Is it the first, or the last, constellation

While some call the next constellation in our parade the last constellation of winter, others call it the first one of spring. Since this constellation rises in late January and early February I tend to think of it as a winter constellation. That is the constellation Cancer, the Crab.

Cancer is a zodiacal constellations and can be found between Gemini, the Twins and Leo, the Lion.

It has the form of the letter "Y," or for those of us who grew up in the '60s a peace symbol, or for others the hood ornament on a Mercedes Benz automobile.

Cancer is a very dim constellation with the major stars being only 4th magnitude. From town this constellation will be difficult to find, however, from a dark-sky site it will be easier to locate.

The centerpiece of Cancer is M44, a very nice star cluster more commonly called the Beehive or by others Praesepe, the Manger. It is called a manger because some of the stars of Cancer were associated with donkeys in ancient times and the little fuzzy spot was thought to be the manger where they fed. You can find it near the center of the constellation. Use binoculars, or for a really good look use a telescope.

In former times Cancer marked the spot on the ecliptic (the path the Sun follows around the sky) of the Summer Solstice, or the farthest north the Sun went during the year before starting its journey south again. This point was 23 and one-half degrees north of the celestial equator and was called the Tropic of Cancer. Conversely, the southern point, 23 and one-half degrees south of the celestial equator, is called the Tropic of Capricorn because the Autumnal Solstice was located there. Twenty-three and one-half degrees is the exact tilt of the Earth's axis. The point marking the Summer Solstice now is located in the constellation Gemini.

The movement is due to a process called precession of the equinoxes, where precession simply means movement. As seen from Earth the location of the stars seems to move over a period of time, that movement is also called precession and is due to a wobble in the axis of the Earth. Kind of like a toy top when it is winding down, it will begin to wobble on its axis. The Earth is doing something like that, not that its spin is winding down.

The change in the location of the stars was discovered by Hipparchus in 120 B.C. so it is not something new.

This spin also causes a change in the celestial poles, north and south. Because the axis, extended out into space, will point at a location. The star nearest that location will be the star marking the north and south celestial poles. Currently the North Star is Polaris but there isn't a South Star because there is no star near where the south pole points.

This wobble proscribes a circle on the heavens and in a few thousand years the North Star will be Vega in the constellation Lyra. The wobble takes 25,800 years to complete.

SKY WATCH: You still have some time to catch Mercury in the evening sky after sunset. Look in the west near where the Sun went down, tiny Mercury will be below and to the right of bright Venus. Saturn is visible in the east, look about two hours after sunset. The ringed planet is located just above bright Regulus in Leo. For Morning observers, Jupiter is a fine sight in the southeast located near Antares, the heart of Scorpious. On February 12 the duo will be joined by a waning crescent Moon.

Next time, something completely different.