Happy to say that I am making good progress with this project. I am titling the book

Conversations with Āryabhaṭa: about Indian Calendars (and Astronomy) 

I hope to complete the writing of the book in the next 3 to 4 months. The book should run to around 80,000 words. It will have a lot of figures, so it may go to between 300 and 400 pages.

Will keep you informed on progress.

Please go to this link in my author website for an page on the contents of the book.