When is Ascension Day?

1The former treatise have I made, O Theophilus, of all that Jesus began both to do and teach, 2Until the day in which he was taken up, after that he through the Holy Ghost had given commandments unto the apostles whom he had chosen: 3To whom also he shewed himself alive after his passion by many infallible proofs, being seen of them forty days, and speaking of the things pertaining to the kingdom of God: 4And, being assembled together with them, commanded them that they should not depart from Jerusalem, but wait for the promise of the Father, which, saith he, ye have heard of me. 5For John truly baptized with water; but ye shall be baptized with the Holy Ghost not many days hence. 6When they therefore were come together, they asked of him, saying, Lord, wilt thou at this time restore again the kingdom to Israel? 7And he said unto them, It is not for you to know the times or the seasons, which the Father hath put in his own power. 8But ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and in all Judea, and in Samaria, and unto the uttermost part of the earth. 9And when he had spoken these things, while they beheld, he was taken up; and a cloud received him out of their sight. 10And while they looked stedfastly toward heaven as he went up, behold, two men stood by them in white apparel; 11Which also said, Ye men of Galilee, why stand ye gazing up into heaven? this same Jesus, which is taken up from you into heaven, shall so come in like manner as ye have seen him go into heaven.