You can be quite demanding to others, too. If you were born in the beginning of January, the sun is in the middle of Capricorn. Then you have great perseverance. If you were born in the middle of January, the sun is at the end of Capricorn. Then you have a tendency to be impatient and take on tasks that may be too much even for you. Occasionally — actually quite regularly — you push yourself too much.
The star constellation Capricorn, represented by a sea-goat, the mythological animal. Illustration from Firmamentum, by Hevelius The sun in the horoscope also represents your father the mother is represented by the moon. That means your Capricorn traits reveal something about the characteristics of your relationship with your father.
If you have the sun in Capricorn, your relation to your father is one of mutually high demands.