Pricing

Most of Lunar can be used for free forever.

Lunar Pro is a paid upgrade that gives you access to the more advanced features explained below.

For $23 or €20 you'll get a Lunar Pro license and 1 year of free updates. The license never expires and can always be activated on Lunar versions released in the year of free updates.

If any update is released after the year of free updates ends, you may:

• Ignore the update and keep using Lunar Pro on the last version you have installed
• Update for free and use the new version without the Pro features
• Purchase another license with another year of free updates

Lunar is not the kind of app that needs a lot of updates, so in theory you should be able to keep using Lunar forever with just 1 license.

This isn't a subscription. But if any major update is needed in the future (like the M1 transition required), this system allows me to get paid for the huge amount of effort these transitions need.

Synchronise the brightness of your built-in display to all your external monitors.

Supported sources

• MacBook display
• iMac display
• Apple monitors with integrated light sensor
  • LG Ultrafine
  • Pro Display XDR
  • Useful if you use a Mac Mini or a MacBook with the lid closed

Description

If you have "Automatically adjust brightness" enabled in System Preferences, macOS will always adapt the internal display to the ambient light around you using its internal light sensor near the webcam.

Lunar can take advantage of that by continuously polling the MacBook display and sending every brightness change to the external monitors.

Dynamic polling interval

Lunar polls the internal display for brightness changes in the following way:

• Every 2 seconds the display brightness is read and compared to the last value
• If the brightness has changed, Lunar starts a fast polling process where the brightness is read every 100ms
• if no new brightness change has been detected in the last 3 seconds, Lunar switches back to the efficient polling interval of 2 seconds

The 2 seconds interval is user configurable to any value greater or equal to 1 second.

Source displays

Lunar is not limited to syncing the brightness from the MacBook display. You can use any monitor as a source as long as it has a light sensor and supports Apple’s native brightness changing protocol.

Monitors that are known to match this criteria:

• LG Ultrafine
• Pro Display XDR

To use a monitor as a source, click on the gear icon menu (⚙️) on the display page and toggle the Sync Mode Role to Source.

Brightness keys (and TouchBar)

Because Lunar is constantly listening for brightness changes, you may keep adjusting your source display using the brightness keys, TouchBar sliders or Control Center from the menu bar, and your external monitors will get those adjustments as well.

You can also adjust external monitors separately using Ctrl+Brightness Up/Down.

Curve algorithm for Sync Mode

When Lunar detects a brightness change, it doesn't send the brightness value of the internal display as it is. Instead the value is passed through an algorithm that is constantly adapting to your manual adjustments so that the perceived luminosity stays the same across all monitors.

This is needed because some monitors can look brighter than others with the same brightness value. For example the MacBook display has 500 nits of brightness which is very bright compared to other monitors, so 50% brightness on MacBook’s display may look noticeably brighter than 50% on your external monitors (which usually have around 300-400 nits).

The curve algorithm can be manually adjusted using the Curve Factor value on the Configuration page.

Lunar can also learn from your personal light perception and readjust the curve whenever you manually change the brightness of an external monitor so that, over time, the brightness computed by Lunar will get closer and closer to what you need.

Adapt the brightness of your monitors based on the sun position in the sky.

If you use your monitors in a room with lots of natural light, Location mode might be a good choice.

Location sources

Lunar will ask for Location Services permissions when you first launch it, and will fetch your last coordinates to compute the sun position throughout the day.

If Location Services permissions are not granted or if there are no valid coordinates, Lunar will try an IP Geolocation service like ipstack.com

If both methods fail, Location mode will be unavailable as a choice.

Function

The way Location mode works is pretty simple:

• When the sun is at its zenith (highest position in the sky, noon), Lunar will set all the monitors to their Max Brightness
• When the sun is below the horizon (between twilight and dusk), Lunar will set all the monitors to their Min Brightness
• Anything in between is passed through the Curve Algorithm to compute a fitting brightness for each monitor

Curve Algorithm for Location Mode

This is the algorithm that converts the sun position (in degrees relative to horizon) to a brightness value specific to each monitor.

The curve algorithm can be manually adjusted using the Curve Factor value on the Configuration page.

Lunar can also learn from your personal light perception and readjust the curve whenever you manually change the brightness of an external monitor so that, over time, the brightness computed by Lunar will get closer and closer to what you need.

Use an external Ambient Light Sensor to adapt your monitors.

The light sensors integrated in the MacBook and iMac are the best around. But in some cases, an integrated light sensor is not available. Some of these cases include:

• Mac Mini
• MacBook with lid closed (clamshell mode)
• Hackintosh
• Mac Pro

Lunar can read the ambient light using an external sensor that can be either wireless or connected through USB.

The functioning principle is similar to Sync Mode: every 2 seconds the lux value of the ambient light is read from the sensor and passed through the Curve Algorithm to be computed into a fitting brightness for each monitor.

To read about how you can make your own ambient light sensor for Lunar, check this page: DIY Ambient Light Sensor

Curve Algorithm for Sensor Mode

This is the algorithm that converts the ambient light (in lux) to a brightness value specific to each monitor.

The curve algorithm can be manually adjusted using the Curve Factor value on the Configuration page.

Lunar can also learn from your personal light perception and readjust the curve whenever you manually change the brightness of an external monitor so that, over time, the brightness computed by Lunar will get closer and closer to what you need.

The free version of Lunar allows you to control the monitor's brightness, contrast, volume and switch inputs, using either hotkeys, Media Keys, UI or through the command line integrations.

The only difference with Pro here is that brightness and contrast adjustments have a limit of 100 adjustments per day.

An adjustment is counted towards the limit only after you have finished fiddling with the brightness/contrast value.

For example, the following actions will only count as 1 single adjustment:

• Press the Brightness Up key 3 times to get from 5% to 25%
• After 5 seconds you notice that the brightness is a bit too high and press Brightness Down one time to go to 20%
• After another 5 seconds, you hover over the menu bar icon to open the Quick Actions menu and scroll to fine tune the Contrast so that the whites aren't so jarring in your dark room
• Finally, you press the Brightness Up key again as in lower contrast you need a bit more brightness for legible text

When you have done 100 adjustments in a day and the limit is reached, any new adjustment will show this dialog:

The Pro license lifts this limit and you can do as many adjustments as you want.

Light up your face in video calls.

How it works

FaceLight can turn your monitor into a really bright LED panel to light up your face when you're having video calls in a dark room.

The default hotkey for toggling FaceLight is Control+Command+5. You can activate FaceLight from the Lunar menu.

1. Simply move your cursor on the monitor you want to use as the light and press the hotkey to activate FaceLight
2. Lunar will increase the active monitor's brightness and contrast to maximum and place a warm-white overlay on top of your screen
3. Press the hotkey again to deactivate FaceLight and return to the previous brightness