The Dogmatikon of Tone 1 sung after "Now and ever and unto ages of ages. Amen." at the Lamplighting Stichera before "Tranquil Light."
The Dogmatikon always has at its focus the Theotokos.
It is sung at every Great Vespers (Saturday Night) for a Sunday of Tone 1 regardless of the tone of the Doxastikheron (the Stikheron after "Glory be to the Father...") or on Fridays of the Great Fast at Vespers or Presanctified according to the tone of the Doxastikheron.
It can be found in the MASI Vespers on pp. 46-47
lyrics
Let us sing a hymn of praise to the Virgin Mary, glory of the whole world! She was herself formed by human seed, yet she became the Mother of the Master, the Gate of heaven, the them of the angels' hymn and the beauty of the faithful. She was seen as being heavenly and the Tabernacle of the Godhead. She indeed tore down the was of enmity between God and man, and brought peace in its place. She opened the kingdom of heaven. Let us therefore cling fast to her for she is the anchor of faith, and let us receive as our stronghold the Lord who was born of her. Be of good cheer, then, and have confidence, O people of God, for He will fight our enemies for us; He is all-powerful!