Basically a lens flare is a bright light trying to make a rainbow inside of your lens. Aiming in the direction of the moon is what was doing that to you. How badly a lens may flare is dependent mostly on the quality of your lens and F-stop used.
For the record as future readers visit, I have to correct myself in that the bright "star" is Jupiter, not Venus. Pleiades and Orion are very identifiable and I cross-referenced to Stellarium for the Jan 8 night sky.
