"An Astrologer's Day" has a deceptively simple plot, although the full significance of the story becomes evident only after a second or even third reading. Part of the difficulty arises from the fact that the author deliberately avoids markers that would benefit the reader: there is no clear indication where the story occurs or when it does, although it is possible to make an educated guess about both. The story begins almost in medias res (in the middle) and concludes on what appears to be an ambiguous note. But, in fact, the story is a tightly knit one in which all parts fit together

."An Astrologer's Day" begins with a general description of an astrologer, who is one of many street vendors, except for the fact that he has a distinct aura of holiness and power. He is working in a busy, unnamed city, and the author establishes that, in reality, he is a charlatan with no special powers other than the keen ability to judge character. The astrologer is about to return to his home at the end of the day when he is stopped by an unusually aggressive customer. The customer insists that the astrologer tell him the truth about his life, and that if he does not, he should return his (the customer's) money, along with extra, as payment for having lied. The astrologer, realizing that he will most likely be exposed, tries to get out of the deal, but the customer is adamant.

The story takes an unexpected turn, when, unbeknownst to the customer, the astrologer recognizes him and tells him about something that happened in the past. Calling the customer by name, the astrologer recounts how the customer had once been stabbed and left for dead, but had been saved by a bystander. The astrologer tells the customer that he must stop looking for the man who stabbed him so long ago, because to do so would be dangerous, and anyway, the perpetrator is dead. The customer, not recognizing the astrologer, is impressed that he should know about his past.

When the astrologer goes home, his wife asks about his day. He tells her that he has been relieved of a great load; he had once thought that he had killed someone, but had today discovered that the victim was well and very much alive. The wife is mystified, but the astrologer goes to bed for an untroubled night of sleep.
The Uses of Irony
Can we always tell the difference between good and evil? Are
good people always good and evil people always bad? In "An
Astrologer's Day," R. K. Narayan provides no answers to these
questions. In the world he creates here, almost nothing is what it
seems to be, and one unexpected event follows another--for both
readers and characters. R. K. Narayan's tale of an astrologer and his
victim is a comic but thought-provoking story in which irony--the
contrast between expectation and reality--is used for several
purposes: to make us doubt the astrologer, to build suspense, and to
develop theme.
From the first sentence, Narayan uses irony to make us doubt
the astrologer's character. His "professional" equipment (the shells,
the cloth with mysterious writing, and so on) is only for show.
Ordinary listening skills, not the stars, help him astonish his "simple
clients" with "shrewd guesswork." Because the narrator tells us that
the astrologer doesn't know the future, calling his work "an honest
man's labor is irony with a sharp bite. The narrator's comments
expose the astrologer as a fake who has discovered a convenient way
to make a living.
The author uses irony to build suspense during the
fortunetelling scene. When Nayak challenges the astrologer to answer
some specific questions about his future, we expect the astrologer to
fail, since he is, according to the narrator, a fraud. Instead, the
astrologer produces a surprising amount of accurate information
about Nayak, including his name. He knows that Nayak is from the
north, and he knows that long ago Nayak was stabbed, thrown into a
well, and left for dead. The astrologer even knows that Nayak's
assailant "died four months ago." Nayak is now convinced, of course,
that the astrologer is genuine, and at the end of the episode, we areleft wondering if the astrologer is the fake that the narrator made him
out to be.
The strongest irony in this story, however, runs through the
entire plot and helps develop the story's theme. It is dishonest to take
money for fake prophecies, but the astrologer's customers are
"astonished" and "pleased" by what he tells them. Although the
astrologer has tried to escape his past, he ends up, in a way, bringing
it back to himself; he's become an astrologer to get away from his
crime-stabbing Nayak and leaving him for dead-but his victim is
attracted to him because he is an astrologer. His astrologer's
guise--"forehead resplendent with sacred ash and vermilion,"
"saffron-colored turban," and "dark whiskers"--prevent Nayak from
recognizing him. Once the astrologer recognizes Nayak, however, he
uses the truth to deceive him. It is the astrologer who once committed
a violent crime, but we can infer from Nayak's behavior and the
astrologer's confession to his wife that Nayak was--and still is--a
violent man. Every situation in this story takes an unexpected twist.
Nothing turns out as we, or the characters, expect.
The irony is so strong in "An Astrologer's Day" that good, evil,
crime, and punishment areri t clear-cut. First, an astrologer who
satisfies his customers with the things he says is revealed as a fake.
Then, the fraud suddenly seems to have supernatural knowledge.
Finally, all our expectations and judgments are turned inside out and
upside down by the astrologer's revelations to his wife at the end of
the story. In R. K. Narayan's world, irony seems to be the rule rather
than the exception.

It talks about how the astrologer comes across a guy called Guru Nayak whom he had tried to kill when he was young..
the main theme of this story is : Role of fate in mans life
Another theme is revenge and punishment for which Guru Nayak comes in search of the astrologer to find him and take his revenge ..maybe by killing the astrologer.

1. “His forehead was resplendent with sacred ash and vermillion, and his eyes sparkled with a sharp abnormal gleam which was really an outcome of a continual searching look for customers, but which is simple clients took to be a prophetic light and felt comforted.”

i) Whose appearance is being described here? What more do we learn about him and his profession?

----The extract describes the astrologer’s appearance in a succinct yet very clear manner.
His appearance is striking. His forehead being painted with holy ash and vermillion dazzled in a conspicuous manner while the strange gleam in his eyes seemed to be a visionary one to his clients although that is actually the result of his perpetually searching for customers. It is self-evident that he is a soothsayer.

ii) What else does the writer tell us about his eyes in the lines that follow?

----The charisma of his eyes is intensified as the pair of eyes is flanked by the bright forehead on one side and the dark whiskers streaming down his cheeks on the other. Narayan humourously says here that even a fool would look charismatic with such singularly impressive features.

iii) The writer takes pains to describe the impressive appearance ‘he’ has. What are the highlights of that description?

----The astrologer has not only the traditional paste of holy ash and vermillion applied on his forehead but also wears a bright gleam in his eyes. The position of his eyes between the dazzling forehead and the streaming beard announce his trade to his clients loud and clear. The saffron-turban which he wears adds a telling effect to his overall appearance.

iv) Where did he ply his trade? How did the setting help in attracting his customers?

-----He pursued his trade under a tamarind tree standing beside a pathway running through the Town Hall Park.
The setting was an ideal one because a large crowd went up and down the pathway from morning till night and a good number of them were the astrologer’s prospective customers. Moreover, the man had interesting peddlers as his neighbours, some of whose customers would get drawn to him to know their future.

v) Who were the other traders and vendors who did their business around him?

-----A man sold medicines near him. Another peddled junk goods and stolen hardware at throw-away prices. A magician would be showing sleight of hands while another would create enough interest among the passing crowd by auctioning cheap clothes. And then there was the hawker who drew a good crowd around him because of his excellent salesmanship. He would sell the same fried groundnuts every day but would canvass his fare in different fancy names like Bombay Ice Cream, Delhi Almond, and so on and so forth on different days.