diff --git a/README.md b/README.md
index f8cf2e8..2f546fc 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 # Moon phases
-Make your sky change follow a cycle
+Make your moon follow a realistic cycle
 
 __Important__: This mod requires at least Minetest 5.2.0 for the game's new sky API.
 Make sure you have the latest version installed or [update your game](https://www.minetest.net/downloads/).
@@ -33,6 +33,6 @@ All source code is licensed under GNU LESSER GENERAL PUBLIC LICENSE version 3.
 You can find a copy of that license in the repository.
 
 ## Media
-All included moon textures are resized versions of graphics from *NASA's Scientific Visualization Studio*.
-These images are part of the Public Domain.
+All included moon textures are resized versions of graphics from *NASA's Scientific Visualization Studio* by [Ernie Wright](https://svs.gsfc.nasa.gov/cgi-bin/search.cgi?person=1059).
+These images are part of the Public Domain as CC-BY-SA 3.0.
 You can access the entire (high resolution) album on [their website](https://svs.gsfc.nasa.gov/4769#28564). See [NASA's media guidelines](https://www.nasa.gov/multimedia/guidelines/index.html) for more information on licensing.
diff --git a/depends.txt b/depends.txt
index 5280a97..658ff4e 100644
--- a/depends.txt
+++ b/depends.txt
@@ -1 +1,2 @@
-skylayer?
\ No newline at end of file
+skylayer?
+datastorage?
\ No newline at end of file
diff --git a/init.lua b/init.lua
index 5a57b5b..897e2b2 100644
--- a/init.lua
+++ b/init.lua
@@ -18,9 +18,6 @@ local function get_cycle_config()
 end
 
 local PHASE_LENGTH = get_cycle_config()
-if state.day >= PHASE_LENGTH then
-	state.day = 1
-end
 
 local function set_texture(player, texture)
 	local sl = {}
@@ -46,8 +43,7 @@ local function handle_time_progression()
 	local time = minetest.get_timeofday()
 	if time >= 0.5 and state.change_time then
 		state.day = state.day + 1
-		if state.day == PHASE_LENGTH then
-			state.day = 1
+		if state.day % PHASE_LENGTH == 0 then
 			state.phase = (state.phase % 8) + 1
 			state.change_time = false
 			update_textures()