Feast of the Ascension term "Holy Thursday" to mean Ascension Day is rare, and the term is more generally applied by most Christian denominations to Maundy Thursday in Holy Week. In Western Christianity, the earliest possible date is April 30 (as in 1818 and 2285), the latest possible date is June 3 (as in 1943 and 2038). In Roman Catholicism, the Ascension of the Lord is a Holy Day of Obligation and in the Anglican Communion, Holy Thursday is a Principal Feast. The three days before Ascension Thursday are sometimes referred to as the Rogation days, and the previous Sunday — the Sixth Sunday
Armelin's calendar Armelin's calendar Armelin's calendar was developed around 1887 by French astronomer Gustave Armelin, who developed a twelve-month calendar in which the year of 364 days was divided into four equal quarters of 91 days. Armelin's calendar proposal was discussed chiefly under the auspices of the Société astronomique de France in 1887 and recently in the French Academy of Sciences. The advantages of this simple system are evident. The months are nearly equal in length, and all have the same number of business days. Any given day of any month falls on the same day of the week each year. A