Extend your Mac display to another Mac with Luna Display 4.0

You can now extend or mirror your main Mac's screen onto a second Mac as easily as you can with Sidecar and an iPad with Luna Display 4.0.

Before Sidecar in macOS Catalina, firms including Luna Display provided the same ability to use an iPad as a second display. Now the latest version of Luna Display 4.0 lets you do the same thing, but with either an iPad or a spare Mac.

The company calls it Mac-to-Mac-Mode and says that the aim is to make the most out of multiple Apple devices at once.

"Apple has always marketed its products to be standalone, never intended to be used at the same time." says the firm in a statement. "While you can connect devices through AirDrop, or pick up where you left off in Safari and the Messages app, the idea remains the same: it is all about picking up one product, and setting the other down."

"Where we differ from Apple is that, instead of limiting ourselves to using each product individually, we see the potential that comes from a combination of products that is greater than the sum of its parts," it continues.

Apple's Sidecar requires macOS Catalina to work with an iPad, but is also limited to certain newer Macs. Luna Display 4.0 brings the feature to older models, with the main Mac needing 2015's macOS El Capitan or later.

The secondary Mac, the one used as an extra display, can be running an even older OS, going back to 2012's macOS Mountain Lion.

Luna Display is a combination of a hardware and software product. The hardware aspect is a dongle that you plug into the main Mac, and comes in versions for either USB-C or Mini DisplayPort.

The software element is an app that must be run on both machines. Luna Display works only wirelessly, and the two devices must be on the same Wi-Fi network.

Luna Display costs $69 direct from the developer, and there is a launch discount of 25%.

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22 Comments

davgreg 1050 comments · 9 Years

About 5 years ago

Duet allows you to use the gizmo bar from laptop world on your iPad display.

sirozha 801 comments · 15 Years

davgreg said:

Duet allows you to use the gizmo bar from laptop world on your iPad display.

Duet doesn't support a Mac-to-Mac extended Display. The big question is if this solution supports extending the display to a 5K iMac. If it does, you can get an amazing deal on the late 2014 iMac with a 5K display. How much lag would there be? Someone, please test this solution and report.

Mike Wuerthele 6906 comments · 8 Years

sirozha said:

davgreg said:

Duet allows you to use the gizmo bar from laptop world on your iPad display.

Duet doesn't support a Mac-to-Mac extended Display. The big question is if this solution supports extending the display to a 5K iMac. If it does, you can get an amazing deal on the late 2014 iMac with a 5K display. How much lag would there be? Someone, please test this solution and report.

Developer says the 5K works fine. That is a lot of data to pass, though, and we'll see what we can do about getting it tested.

anome 1545 comments · 16 Years

That is an interesting idea, but what about keyboard and mouse access? If I connect my MacBook Pro to use my iMac (or Mac mini or Mac Pro) as an external monitor, can I use the keyboard and mouse/trackpad connected to the desktop to control the MacBook? In other words, can you use it as a full KVM solution? Because, for me, that would be a killer option. Especially as I've been trying to work out how to rig a KVM switch to a Mac using a Magic Keyboard and Magic Trackpad. (The simplest way seems to be to have them permanently plugged in via Lightning cables, which seems redundant.)

Mike Wuerthele said:

sirozha said:

davgreg said:

Duet allows you to use the gizmo bar from laptop world on your iPad display.

Duet doesn't support a Mac-to-Mac extended Display. The big question is if this solution supports extending the display to a 5K iMac. If it does, you can get an amazing deal on the late 2014 iMac with a 5K display. How much lag would there be? Someone, please test this solution and report.

Developer says the 5K works fine. That is a lot of data to pass, though, and we'll see what we can do about getting it tested.

Frankly, I don't understand how it would work, since even Thunderbolt2 bandwidth is not sufficient for the 5K signal to pass. It may work with the 5K iMac, but I doubt it will work at the 5K resolution. The refresh rate will most like be affected too: I doubt that even 30 fps is possible.