Luna Display's Mac-to-Mac Display Feature Now Works Over Ethernet and Thunderbolt Wednesday May 5, 2021 1:14 pm PDT by Juli Clover Astropad's Luna Display accessory that's able to turn an old iPad or Mac into a secondary display for a primary Mac was today updated with a new feature that's designed to allow Mac-to-Mac mode to work over Ethernet and Thunderbolt. play The Luna Display is an alternative to Apple's Sidecar, allowing an iPad to be used as a display for a Mac. Unlike Sidecar, it works with other Macs, so you can use one Mac as a display for another Mac, something that's always been useful with machines like the iMac.