Nadir (IMUM COELI) and Zenith (MIDHEAVEN) are important aspects to understand about natives psychology and persona.
Nadir is 4th house of horoscope i.e; where sun is at midnight and Zenith is 10th house of horoscope where sun is at mid-day.
Nadir is at the lowest point below from the observer or native and Zenith is at the highest point above from native. Lowest point while birth of child is 4th house and Highest point from it is 10th house. Planets and their relation with these position are of great impotance in Astrology.
In vedic jyotish Sage Parashara have said: 4th house is soul and 10th house is most powerful kendra of all (quadrant).
Nadir being the deepest point (4th house) signifies the deep insights of our mind, even of which we are not aware about. 4th house is our sub concious mind. Our thoughts and actions without intention are seen from here.
Like a revengeful person is wrong spiritually but could be correct in his own way. This is because we are always unaware about our actual being, we feel our existence from our thoughts. Our thoughts tells us we exits but in reality we dont realize our existence of energy, which makes us dependent on our thoughts completely with an illusion that they are ultimate truth of existence. Thoughts which are making us feel our existence come from Nadir, to attain and realize complete knowledge about our real existence this point Nadir must be free from all types of sorrows and emotions (i.e; detachment from all).
Sages have told about seven types of emotions, what emotion are being carried by our Soul from past experiences and memories are to be observed from 4th house of horoscope and planet Moon. These are the thoughts which doesnt arises from what we do, see, speak or hear, it arises from stored sub concious memories.
Zenith being the highest point (10th house) signifies what we know about the self, this is the knowledge of our own being. Like I can do this, I know this, I own, its the ‘I’ factor within us. In reality complete universe reside within us, but from that whatever energy, skill, talent, ability or perfection we innovated within about ‘I’ is to be seen from Zenith. This is our reflection to outside world, its our persona. Its about what people will percieve and think about us.
10th house of horoscope is whatever you do, its your reflection to outside, how do people percieve your reflection is your persona. Importantly perpection about us is dependent on our reflection and not on people percieving, In reality we are unware about it and we believe they are percieving it like that but actually we are reflecting it like that.
Sages have told 10th house for karma (profession and livelihood). Jupiter, Mercuy, Sun, Mars and Saturn are significator for this house.
What is in insights of 4th house is reflected out by 10th house of horoscope.