I’ve uploaded DaylightXL 1.3 to Apple. This will hopefully fix the crashes some people have experienced when trying to change the type of twilight used. If not, please let me know, preferably enclosing crash logs.
The new version also offers to draw estimates of twilight on the main map display.
It should appear in the AppStore next week.

TweetMapper
TWorldView is now TweetMapper. The AppStore should update within 24 hours.