Jesus Christ was crucified on Friday, April 3, in 33 A.D., according to two Oxford University professors.

The claim was contained in an article in the Journal of the American Scientific Affiliation, a periodical for evangelical Christians who are scientists.

Colin J. Humphreys and W. Graeme Waddington said they based their conclusions on astronomical calculations and biblical interpretation.

Humphreys, a professor of metallurgy, and Waddington, a physicist, cite writings from Cyril of Alexandria and Pontius Pilate that indicate the moon turned a blood-red color during the Crucifixion. The scholars say such a color change would take place only during a lunar eclipse.

Using astronomical calculations, the authors say the only lunar eclipse visible from Jerusalem during the period of A.D. 26 to 36 -- which is generally accepted as the period during which Christ's Crucifixion occurred -- was one on Friday, April 3, A.D. 33.

Although Christians today generally believe that Jesus was 33 years old at the time of his crucifixion, there is disagreement as to the year of his birth. The Crucifixion has been variously dated at March 25, A.D. 29, and April 23, A.D. 34, a calculation arrived at by Sir Isaac Newton.

Professors Humphreys and Waddington say the date is more than just trivia. They believe it to be directly relevant to the length of Jesus' ministry and to the date and nature of the Last Supper.

They have tried to demonstrate that the Cruxifixion took place a day before Passover, when the Passover lamb would have been slaughtered by Jewish custom. This would agree with the New Testament comparison of Jesus with the lamb, and would rule out the belief that the Last Supper was a Passover meal.