The Ascension of Our Lord, which occurred 40 days after Jesus Christ rose from the dead on Easter, is the final act of our redemption that Christ began on Good Friday. On this day, the risen Christ, in the sight of His apostles, ascended bodily into Heaven (Mark 16:19, Luke 24:51, and Acts 1:2). Christ was raised up by His own powers. Tradition designates Mount Olivet near Bethany as the place where Christ left the earth. The feast falls on Thursday. It is one of the Ecumenical feasts ranking with the feasts of the Passion, of Easter and of Pentecost among the most solemn in the calendar, has a vigil, and, since the fifteenth century, an octave which is set apart for a novena of preparation for Pentecost. This is a Holy Day of Obligation.
"Today our Lord Jesus Christ ascended into heaven; let our hearts ascend with him. Listen to the words of the Apostle: If you have risen with Christ, set your hearts on the things that are above where Christ is, seated at the right hand of God; seek the things that are above, not the things that are on earth. For just as he remained with us even after his ascension, so we too are already in heaven with him, even though what is promised us has not yet been fulfilled in our bodies." – St. Augustine