Final answer:
The Twilight mentioned in the Sonnet refers to the transition between day and night. The Dargah of Sheikh Salim Chishti is located in Fatehpur Sikri.
Step-by-step explanation:
The Twilight mentioned in the Sonnet refers to the time of day when the sun is below the horizon but its rays still illuminate the sky. It is a poetic term used to describe the transition between day and night.
The Dargah of Sheikh Salim Chishti is situated in Fatehpur Sikri, which is a town in India. Fatehpur Sikri was the capital of the Mughal Empire during the reign of Emperor Akbar. The Dargah is a famous shrine dedicated to the Sufi saint Sheikh Salim Chishti.