The protagonist in "An Astrologer's Day" is an interesting character because he is a survivor. He came to the big city from one of the many small villages in India and had to find some way to exist without having any formal education or marketable skills. We do not know how he obtained his astrological paraphernalia, but it is possible that he found it somewhere and decided to become an "astrologer" on the spur of the moment. His "professional equipment" consists of

...a dozen cowrie shells, a square piece of cloth with obscure mystic charts on it, a notebook, and a bundle of palmyra writing.

The man who had owned the equipment before him may have been better versed in the pseudo-science of astrology, but he may have lacked the present owner's intelligence, glibness, personality, and "moxie." It is obviously very hard for any astrologer to make a living in this city because most people don't have any money to spare for anything but the bare necessities.

The astrologer's day is a long and precarious one. He has a wife and small daughter waiting for him at home. Even when he encounters Guru Nayak and his life is in danger, he resolutely insists on talking about money. Because of his brains and adaptability, he is able to bring home even more coins than usual. He lives from day to day. He doesn't even want to think about what he is going to do tomorrow. He has gotten through one day and that is enough for him.

"Time to sleep," he said, yawning, and stretched himself on the pyol.

The astrologer might be said to represent the millions of men who are migrating to the big cities of India from the villages. His story is just one of the many stories of these people, whose survival in the cities depends on their adaptability to very difficult living conditions.

He had left his village without any previous thought or plan. If he had continued there he would have carried on the work of his forefathers namely, tilling the land, living, marrying, and ripening in his cornfield and ancestral home. But that was not to be.

It is interesting to see how this nameless man has become transformed into a big-city dweller who deals with great numbers of people every day in order to eke out a living for himself and his tiny family. He needs money to survive and support his family, and he has to get that money from other people by providing something in exchange. The great subcontinent of India is changing in many ways because of globalization, expanding population, and other factors. "An Astrologer's Day" represents the macrocosm in a microcosm, which it what makes it such a memorable short story.

What character traits does the astrologer have? 

The astrologer has many positive character traits. He is self-reliant, intelligent, resourceful, courageous, and industrious. He is willing to work as long as ten or  twelve hours a day every day of the week in order to earn a tiny amount of money to support himself, his wife, and his little daughter. He obviously does not have much of an education. He would have been a simple peasant if he hadn't gotten into a quarrel with Guru Nayak back at their village and had been forced to flee to a big city because he thought he had killed the other man with a knife.

He had left his village without any previous thought or plan. If he had continued there he would have carried on the work of his forefathers--namely, tilling the field, marrying and ripening in his cornfield and ancestral home.

Once in the city he had to find a means to exist without a trade and in an overpopulated land where people die of starvation on the streets every night. He may have acquired his so-called "professional equipment" because some other self-styled astrologer couldn't make a living and abandoned them. The astrologer has to be intelligent in order to convince enough people that he can actually tell their fortunes and give them valuable advice. He has learned that most people have similar life problems and can be satisfied with similar advice. When he is confronted by his nemesis Guru Nayak, the astrologer keeps his nerve and actually makes money from the violent man rather than getting killed in revenge.

The reader, like the astrologer's mistrustful client, is startled when the astrologer calls him by name.

"Guru Nayak--"

"You know my name!" the other said, taken aback.

"As I know all other things, Guru Nayak..."

How can this trickster know the client's name? Does he really possess supernatural powers? We do not find out for some time that by the sheerest coincidence the astrologer is being consulted by the man he thought he had killed years ago. He is both alarmed and relieved. At least the man is not dead, and he is not a murderer. But the client is looking for the man who knifed him and intends to kill him if he finds him. 

We have to admire this resourceful astrologer in spite of the fact that he is barely eking out a living from day to day. If he lived in a land that offered better opportunities he might become rich. He can't even afford to have his own illumination in the park but depends on the lights of nearby vendors.  We can only imagine what it must be like if the weather turns bad. If it rains for several days in a row, the astrologer and his family may go hungry. But he has the courage and brains necessary to survive under these harsh conditions, and he has even been sufficiently successful to be able to get married and have a child. R. K. Narayan's story tells a lot about India in describing one day in the life of one man.