A celebration of the Ascension is a great opportunity to remember the theological basis for shared ministry: the gift of the Holy Spirit as emphasised in the readings for the day: “See I am sending upon you what my Father promised… power from on high”; “the riches of his glorious heritage among the saints (i.e. the believers)”; “the Church, which is his body, the fullness of him who fills all in all” “You will receive power when the Holy Spirit has come upon you”. All of this points to the theological idea that the focus moves from the earthly Jesus to the Body of Christ, but both have the same life-giving function in the world, with gifts for ministry given diversely to all the baptised.
A focus for the service could be celebrating the signs of Ascended Christ visible in the gifts and fruit of the Holy Spirit at work in the church and beyond. This is probably more useful than trying to figure out some literal picture of the Ascension!