Name: Dark sky Planner
Rating: 5 (1 reviews)
Author: Tickforge

Dark Sky is an offline app for quickly planning night sky viewing.

It computes astronomical night and moon conditions directly on your watch from your current GPS position, then highlights the darkest moon-free window.

Includes:

4 screens: Tonight, Timeline, Moon, Summary
24h night ring with color meaning
key times: astronomical night start/end, moonrise/moonset, moon illumination
moon altitude graph
in-app date picker for checking other days
fully offline calculations (no phone or internet required)

More details:
https://tickforgeapps.com/apps/dark-sky/