According to the conventional association between birthdays and birth signs, the Sun spends around 30 days traversing each of the 12 zodiacal constellations. There is, in fact, a great deal of variance. Every year, the Sun spends the longest time in Virgo (more than 40 days), but just approximately a week in Scorpius. The shortest period in a constellation is three days in Sagittarius and Pisces.
In addition to these variations from constellation to constellation, there are also variations within each constellation. For example, the Sun has spent only about 28 days in Aries since it was born (March 15-April 18). But it will still be in Aries when it dies--if it doesn't move out of Aries first. And even though March had only 28 days, April had 31 because February had always 0 days last year when they added them to the calendar. So every sign covers up for any missing days by adding an extra day at the end of the month.
Another way to look at it is that Aries covers up for any lost days by adding an entire month to its span. So if the Sun was in Aries for 28 days, it would cover 92% of the sky. If it were in Aries for 29 days, it would cover 100%. As you can see, there's very little difference between these two examples!
But don't worry about those few missing days at the beginning or end of the year.
The sun travels for around 53 seconds every day and spends about 30 days in each sign. Every 28 days, the Moon passes through all twelve signs. Each sign takes around 2 1/2 days to complete. Therefore, the Moon has passed through all 12 signs at least once but may pass through them again.
Every year in late November, the Sun passes through it for about a week. Although the Sun only spends a few days every year in Scorpius, it is a fairly large constellation. The northern point of the scorpion's claws constellation is a short patch of sky (see the chart to the right), which the sun crosses quickly. During this time, observers near high latitude will see a small increase in daylight each day.
The constellation Scorpius is visible from much of the world. It forms a neat rectangle with its feet in the southern hemisphere and its head in the north. It is best seen before midnight when it is rising above the eastern horizon and after midnight when it is setting below the western horizon. The star Antares is located at the heart of the scorpion's claw.
Scorpius is one of the constellations that make up the zodiac. It shares a border with Ophiuchus to form a rough triangle with Sagittarius. Both these constellations are part of what used to be called "the Far North". They are visible in the night sky during the winter months when the Sun is found between the Earth and the Moon. In summer, they disappear over the horizon.
Scorpius is one of the oldest constellations. It was already an established system of stars when Hipparchus mapped the Milky Way around 150 B.C. Since then, many more stars have been discovered inside this constellation, especially using telescopes.
Factoid 2: The Earth rounds the Sun once every 365.24 days. As a result, stars move westward at a rate of little about one degree every day. Every 24 hours, a star will be 3 minutes 56 seconds (3:56) to the west. Every day, the Sun appears to travel eastward against the stars for around 3:56 minutes. This is called "parallax" and is why we can see stars even though they're far away.
The exact figure depends on how far away the star is from us. But since stars are pretty small compared to the distance between them, this number is almost exactly the same for all stars. It's usually given in terms of an angle - the closer it is, the more degrees there are. So if you want to know how many degreesStar A moves each day, just divide 3600 by the distance from us to Star A in miles. For example, the nearest star, Alpha Centauri, is 4.37 light years away from us. That means that it moves through space about 42 degrees each day.
Our galaxy is about 100,000 light years across. So even the closest star to us moves about 1/10 of a degree each day. Which is very tiny!
Stars aren't fixed points in the sky, they float around our Galaxy like boats on water. Our Galaxy is only one among hundreds of billions in the Universe. So even the closest star to us is actually quite far away.
Every day, since the sun takes four minutes longer than the constellations to rotate about us, it moves one degree east along the ecliptic. The sun is thus said to rise at one sunrise and set at another. It actually rises a little before and sets a little after these times, but since it takes the earth 24 hours to complete its rotation, this movement across the sky is equivalent to moving one degree west every hour.
The sun is faint, so observing it directly is difficult. Instead, astronomers watch for its effects on other objects. Light waves travel at a constant speed, so by measuring how long it takes for light to reach us from something else, we can calculate how far away that thing is. The farther away an object is, the more slowly it will be moving when you compare its distance now with its distance then; the closer it is, the faster it will be moving.
For example, if you were watching an airplane flying over your house and timed how long it took for it to get from north to south, you could estimate how high it was flying by comparing the distances it had gone by the time you looked again.