Extend your Mac display to another Mac with Luna Display 4.0

AppleInsider

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.

Extending a single desktop across an iMac and a MacBook Pro. (Photo: Luna Display.)

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%.

davgreg

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

sirozha

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. 

edited October 2019

mike wuerthele

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.

edited October 2019

anome

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.)

sirozha

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. 

edited October 2019

hucom2000

anome said:

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.)

Um.. have you heard of wireless keyboards and mice?

mike wuerthele

sirozha said:

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. 

It's a H.265 stream, not a DVI signal.

screensavers

I just ordered it. It looks very impressive, and I have tons of macs, including a 5K iMac which would make an excellent display for my MacBook Pro.

sirozha

Mike Wuerthele said:

sirozha said:

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. 

It's a H.265 stream, not a DVI signal.

I've just plugged the numbers in the bandwidth calculator, and for the 5K resolution at H.265 with high quality and continuous motion at 60 fps, the required bandwidth is about 300 Mbps. So, I guess it's feasible to do this wirelessly if you have a solid Wi-Fi system that can consistently maintain the throughput of 300 Mpbs. 

edited October 2019

indieshack

So remote desktop does something similar? Does this work with multiple monitors so I could display the other mac on just one of my monitors?

leehamm

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. 

I tested it with an older [2009] iMac as a secondary display, and saw no latency. Today's software upgrade seemed to speed up everything, as I have seen some slow-down with an older [2011] MacBook Air as the primary. I normally use Luna Display with an iPad, so I have a touch screen Mac. It is currently just over $52 for the dongle. Well worth it, imho.

Sidecar can't handle Macs this old!

dewme

As an owner of iPad Pros that do not support SideCar, I really wish that Apple had rolled out a version of SideCar that only supported display functions and dispensed with the support for Apple Pencil. Call it SideCar Lite or whatever, but it seems like any iPad Pro model ever made should be capable of supporting display-only functionality via the lightning connector. Anything better than the WiFi based solutions or lightning based solutions from third parties would be great. I think Apple could do it rather easily, but for focus and prioritization they went only with a high-end solution with all the bells and whistles. 

fastasleep

anome said:

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.)

What? They keyboard and mouse attached/paired with the iMac are gonna control the iMac. This is using your iMac as the second display for your MBP, so you’d need to set it up, then switch your keyboard and mouse to pair with the MBP I guess, if you wanted to do that for some reason.  

fastasleep

dewme said:

As an owner of iPad Pros that do not support SideCar, I really wish that Apple had rolled out a version of SideCar that only supported display functions and dispensed with the support for Apple Pencil. Call it SideCar Lite or whatever, but it seems like any iPad Pro model ever made should be capable of supporting display-only functionality via the lightning connector. Anything better than the WiFi based solutions or lightning based solutions from third parties would be great. I think Apple could do it rather easily, but for focus and prioritization they went only with a high-end solution with all the bells and whistles. 

Soooo... why not use Luna Display or AstroPad or Duet Display?

jdw

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.

I look forward to that review, Mike!

mike wuerthele

jdw said:

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.

I look forward to that review, Mike!

Well, the stumbling block is at present we have no iMac 5K units on hand! But, there are always ways.

sirozha

Mike Wuerthele said:

jdw said:

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.

I look forward to that review, Mike!

Well, the stumbling block is at present we have no iMac 5K units on hand! But, there are always ways.

I can test it. I have a 2018 Macbook Air and a late 2014 iMac 5K. Care to provide a Luna dongle for the test?

mike wuerthele

sirozha said:

Mike Wuerthele said:

jdw said:

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.

I look forward to that review, Mike!

Well, the stumbling block is at present we have no iMac 5K units on hand! But, there are always ways.

I can test it. I have a 2018 Macbook Air and a late 2014 iMac 5K. Care to provide a Luna dongle for the test?

Nope. We've already worked out how to get it done.

docno42

davgreg said:

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

Duet doesn't have near the resolution or speed as Luna, especially if you use a lighting cord between your Mac and iPad.  Wish I had a USB-C cable handy, I'd test my mom's 5K iMac with my MacBook Air.  

docno42

indieshack said:

So remote desktop does something similar? 

Not even close.  There is NO lag or latency with Luna.  Remote Desktop has tons of latency - especially if you are going over wireless connections.