Ascension Thursday has been transferred to Sunday in many dioceses. (Frequent question asked at Catholic rectories: “What time is Midnight Mass this year.”)
The Anglicans seems to stick to Thursday. Beginning in 1902, the choir at St. John’s at Cambridge began the custom of singing from the top of the tower. Here is the chorister Benedict Flinn explaining the tradition.
And here is the choir singing at noon, Ascension Thursday 2018.