Hello,
We have just released our first mobile app - APT Darkness Clock (APT DC) which allow to calculate the Deep Sky Darkness (DSD) time for selected night.
For link and QR code take a look here:
https://www.ideiki.com/astro/MobileApps.aspx
Or navigate directly here:
https://play.google.com/store/apps/d...utions.aptcalc
Hope you will find the app useful