Are there any ways to calculate blue hour times?

[ValeraT1982]

No description provided.

[seaniedan]

I'd say not, since the term is colloquial, it lacks an official definition such as dawn, dusk, or the three stages of twilight.
To save others a click: blue hour refers to the state of natural lighting that usually occurs around the nautical stage of the twilight period (at dawn or dusk).