Nightwatch

Nightwatch is a menu-bar app for planning astrophotography. It combines weather and sky forecasts for your location, finds the nights with a clear and dark window, and ranks the targets you have chosen by when they are best placed. It also offers a desktop widget, alerts before a good window opens, and opt-in modes for aurora alerts and bright nights when darkness never arrives. The same app is on the App Store for Mac, iPhone and iPad, where the README says it is one free purchase; the disk image is the other way to get the Mac version.

It requires macOS 14 or later on Apple silicon. The README says the disk image is signed and notarized. The first time you open it, macOS asks whether to open an app downloaded from the internet; choose Open. Nightwatch asks for your location only when you press the button that uses it. Weather data comes from Open-Meteo and MET Norway, and the NOTICE file in the repository lists those attributions and the other data sources.