How an Octagon Skylight can be made to look like a Round Skylight
A better way to have a round looking skylight (on the interior) is to have an octagon skylight built that fits on an octagon shape curb. After the skylight is installed you can have the interior carpenters install drywall or plywood on the interior of the curb, “rounding” off the corners. After the finish is completed, all you can see is a round curb and a round domed skylight.
This is a better skylight than a round one for several reasons.
One is cost
two is less problems with the performance of the skylight frame
three it is easier to build an octagon curb than paying for a self-flashing round curb mount.