Question: Bombay Time is set at 4 hours and 51 minutes ahead of the mean solar time at what observatory?
Sentence (from "Greenwich Mean Time"): Today GMT is considered equivalent to UTC for UK civil purposes (but this is not formalised) and for navigation is considered equivalent to UT1 (the modern form of mean solar time at 0° longitude); these two meanings can differ by up to 0.9 s. Consequently, the term GMT should not be used for precise purposes.
Relevant evidence: No