What is a Rorate Mass? Here's a nice explanation (pictures at the link):
The Rorate Caeli Mass is a traditional Advent devotion wherein the Mass of the Blessed Virgin Mary for Advent is offered just before dawn. In many instances families and individuals travel an hour or more, rising and arriving very early for this stunningly beautiful Mass. The interplay of light and darkness speak to the meaning of Advent and the coming of the Light of the world.
The Mass takes its title, Rorate Caeli, from the first words of the Introit, which are from Isaiah 45:8:
“Rorate, caeli, desuper, et nubes pluant justum, aperiatur terra, et germinet Salvatorem.”
“Drop down dew, ye heavens, from above, and let the clouds rain the just: let the earth be opened and bud forth a Saviour.”
The Rorate Mass is lit only by candlelight. Because it is a votive Mass in Mary’s honor, white vestments are worn instead of Advent violet. In the dimly lit setting, priests and faithful prepare to honor the Light of the world, Who is soon to be born, and offer praise to God for the gift of Our Lady. As the Mass proceeds and sunrise approaches, the church becomes progressively brighter, illumined by the sun as our Faith is illumined by Christ.
We didn't need to have Mass at a special time; Mass on first Friday, during the school year, is always at 7 am, so I figured that would work. It was certainly before dawn. I told people ahead of time, of course, and I kept a few lights on in church before Mass. It would have been even nicer to have everyone enter church without lights, but that's a bit impractical.
We did use the proper chants, in English, which you can find here; our music director sang them beautifully, despite a nagging cold. I'm told the altar was lovely, light only with candles; it was striking to see everyone's faces, lit only by candlelight. I'm sorry I didn't think to ask someone to take a photo.
While this was a votive Mass for our Lady, I elected to use the readings of the day; they fit very well.
I pondered using incense, and maybe we'll do that next year; as well as trying it at the high altar (i.e., ad orientem).
Were you there? What did you think?