To the mages. The temperature isn't rising above 80 degrees F. or thereabouts. I was on the verge of preparing to go out to catch the bus to go downtown for Holy Mass and then I realised that it being Friday means that there is no 0800 Mass today, tsk. But it is the great feast of Our Lord's Transfiguration (Introibo, CE and here, Wiki).
The feast of the Martyrs Saints Pope Sixtus II, Felicissimus, and Agapitus is commemorated today (Wiki here). Saint Lawrence's feast is upcoming on the 10th; he is one of this group of deacons, evidently, with Felicissimus and Agapitus, but acquired a much more significant cultus.
Charpentier's motet O bone Jesu since there seems to be nothing in the catalogue specifically for the feast of the Transfiguration.
From the expert folks at Neumz, on the Communion, Visiónem quam vidístis.
The Communion antiphon for this day is taken from the Gospel of Matthew, chapter 17, verse 9. A few days after the announcement of his Passion, Christ manifests his divinity to Peter, James and John. Jesus, in the radiance of his divine light, receives the testimony of Moses and Elijah. The melody, clearly asserted in quam vidistis, reflects the imposing character of this vision. The following phrase, nemini dixeritis (“don't tell anyone”), starts with a melodic oscillation around the mode’s tenor, la, and then begins a gradual descent on the Re final. This descent into the grave invites the disciples-- the very ones who will witness the agony of Christ-- to keep this manifestation in the privacy of their hearts. Saint Gregory gives us a pertinent explanation: “In the transfiguration, it was above all a question of removing from the hearts of the disciples the scandal of the cross.”
(It seems not possible to embed the Benedictines of Jouques' version of the antiphon here.)
It is also the feast of Pope Saint Hormisdas (6th century), of Saint Goderannus (11th century), and of Saint Anna (14th century).
V. Et álibi aliórum plurimórum sanctórum Mártyrum et Confessórum, atque sanctárum Vírginum. R. Deo grátias.