Added several tweaks to sunrise/sunset time calculations

app/src/main/java/com/rtbishop/look4sat/MainScreen.kt

@@ -78,6 +78,8 @@ fun MainScreen() {
     val currentKey = backStack.lastOrNull()
     val navigateBack: () -> Unit = { backStack.removeAt(backStack.size - 1) }
     val fadeTransition = fadeIn(animationSpec = tween(350)) togetherWith fadeOut(animationSpec = tween(350))
+//    val slideInTransition = slideInHorizontally(initialOffsetX = { it }) togetherWith scaleOut(targetScale = 0.9f)
+//    val slideOutTransition = scaleIn(initialScale = 0.9f) togetherWith slideOutHorizontally(targetOffsetX = { it })
     val navItems = listOf(Screen.Satellites, Screen.Passes, Screen.Radar(), Screen.Map, Screen.Settings)
 
     val context = LocalContext.current
@@ -125,7 +127,9 @@ fun MainScreen() {
                 popTransitionSpec = { fadeTransition },
                 predictivePopTransitionSpec = { fadeTransition },
                 entryDecorators = listOf(
+                    // Required for saving Compose state per entry
                     rememberSaveableStateHolderNavEntryDecorator(),
+                    // Required for ViewModel scoping per entry
                     rememberViewModelStoreNavEntryDecorator()
                 ),
                 entryProvider = entryProvider {

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/predict/CelestialComputer.kt

@@ -23,6 +23,7 @@ import kotlin.math.PI
 import kotlin.math.abs
 import kotlin.math.acos
 import kotlin.math.asin
+import kotlin.math.atan
 import kotlin.math.atan2
 import kotlin.math.cos
 import kotlin.math.floor
@@ -375,47 +376,75 @@ object CelestialComputer {
 
     /**
      * Find the next sunrise and sunset times from [startMillis] for [observer].
-     * Uses the adaptive iteration from PREDICT v2.2.5's PredictSun().
+     * Uses elevation threshold of -0.8333° to match the standard civil definition:
+     * upper limb on geometric horizon with standard atmospheric refraction (~0.57°)
+     * and solar semidiameter (~0.27°) corrections applied, matching USNO/timeanddate.com.
      */
     fun findSunRiseSet(observer: GeoPos, startMillis: Long): RiseSetTimes {
+        // Standard civil threshold: center elevation when upper limb meets geometric horizon
+        // -0.8333° = standard refraction (~0.5667°) + solar semidiameter (~0.2667°)
+        val threshold = 0.8333
         var daynum = millisToDaynum(startMillis)
         var sunPos = getSunPosition(observer, daynumToMillis(daynum))
 
-        // Find sunrise: iterate until sun elevation crosses zero
+        // Phase 1: if sun is above threshold, fast-forward to well past sunset into night
-        var sunrise = 0.0
+        if (sunPos.elevation > -threshold) {
-        // If sun is already up, move forward until it sets first
+            var guard = 0
-        if (sunPos.elevation > 0) {
+            while (sunPos.elevation > -threshold && guard++ < 500) {
-            while (sunPos.elevation > 0) {
+                daynum += 0.008  // fixed ~11.5 min steps past the setting sun
-                daynum += 0.004 * (sin(DEG2RAD * (sunPos.elevation + 0.5)))
                 sunPos = getSunPosition(observer, daynumToMillis(daynum))
             }
-            daynum += 0.4 // advance past night
+            // Now advance until sun is clearly below minimum (deep night)
-        }
+            guard = 0
-        // Now find next sunrise
+            while (sunPos.elevation > -12.0 && guard++ < 500) {
-        while (sunrise == 0.0) {
+                daynum += 0.02
-            if (abs(sunPos.elevation) < 0.03) {
-                sunrise = daynum
-            } else {
-                daynum -= (0.004 * sunPos.elevation)
                 sunPos = getSunPosition(observer, daynumToMillis(daynum))
             }
         }
 
-        // Find sunset from sunrise
+        // Phase 2: advance until sun starts rising toward threshold (elevation increasing)
+        var guard = 0
+        while (sunPos.elevation < -threshold && guard++ < 500) {
+            daynum += 0.008
+            sunPos = getSunPosition(observer, daynumToMillis(daynum))
+        }
+
+        // Phase 3: converge symmetrically on elevation = -threshold (sunrise)
+        var sunrise = 0.0
+        guard = 0
+        while (sunrise == 0.0 && guard++ < 200) {
+            val delta = sunPos.elevation + threshold
+            if (abs(delta) < 0.01) {
+                sunrise = daynum
+            } else {
+                daynum -= 0.004 * delta
+                sunPos = getSunPosition(observer, daynumToMillis(daynum))
+            }
+        }
+        if (sunrise == 0.0) sunrise = daynum
+
+        // Phase 4: fast-forward through the day until sun drops back below threshold
         daynum = sunrise
         sunPos = getSunPosition(observer, daynumToMillis(daynum))
-        // Move forward through the day
+        guard = 0
-        while (sunPos.elevation > -3) {
+        while (sunPos.elevation > -threshold && guard++ < 500) {
-            daynum += 0.04 * (cos(DEG2RAD * (sunPos.elevation + 0.5)))
+            daynum += 0.008
             sunPos = getSunPosition(observer, daynumToMillis(daynum))
         }
-        // Refine sunset
+
+        // Phase 5: converge symmetrically on elevation = -threshold (sunset)
         var sunset = 0.0
-        while (sunset == 0.0) {
+        guard = 0
-            daynum += 0.004 * (sin(DEG2RAD * (sunPos.elevation + 0.5)))
+        while (sunset == 0.0 && guard++ < 200) {
+            val delta = sunPos.elevation + threshold
+            if (abs(delta) < 0.01) {
+                sunset = daynum
+            } else {
+                daynum += 0.004 * delta
                 sunPos = getSunPosition(observer, daynumToMillis(daynum))
-            if (sunPos.elevation <= 0) sunset = daynum
             }
+        }
+        if (sunset == 0.0) sunset = daynum
 
         return RiseSetTimes(daynumToMillis(sunrise), daynumToMillis(sunset))
     }
@@ -429,37 +458,47 @@ object CelestialComputer {
         var moonPos = getMoonPosition(observer, daynumToMillis(daynum))
 
         // If moon is already up, move forward until it sets
+        var guard = 0
         if (moonPos.elevation > 0) {
-            while (moonPos.elevation > 0) {
+            while (moonPos.elevation > 0 && guard++ < 1000) {
-                daynum += 0.004 * (sin(DEG2RAD * (moonPos.elevation + 0.5)))
+                daynum += 0.004 * sin(DEG2RAD * (moonPos.elevation + 0.5))
                 moonPos = getMoonPosition(observer, daynumToMillis(daynum))
             }
             daynum += 0.4
+            moonPos = getMoonPosition(observer, daynumToMillis(daynum))
         }
         // Find moonrise
         var moonrise = 0.0
-        while (moonrise == 0.0) {
+        guard = 0
+        while (moonrise == 0.0 && guard++ < 1000) {
             if (abs(moonPos.elevation) < 0.03) {
                 moonrise = daynum
             } else {
-                daynum -= (0.004 * moonPos.elevation)
+                daynum -= 0.004 * moonPos.elevation
                 moonPos = getMoonPosition(observer, daynumToMillis(daynum))
             }
         }
+        if (moonrise == 0.0) moonrise = daynum
 
         // Find moonset from moonrise
         daynum = moonrise
         moonPos = getMoonPosition(observer, daynumToMillis(daynum))
-        while (moonPos.elevation > -3) {
+        guard = 0
-            daynum += 0.04 * (cos(DEG2RAD * (moonPos.elevation + 0.5)))
+        while (moonPos.elevation > -1 && guard++ < 1000) {
+            daynum += 0.04 * cos(DEG2RAD * (moonPos.elevation + 0.5))
             moonPos = getMoonPosition(observer, daynumToMillis(daynum))
         }
         var moonset = 0.0
-        while (moonset == 0.0) {
+        guard = 0
-            daynum += 0.004 * (sin(DEG2RAD * (moonPos.elevation + 0.5)))
+        while (moonset == 0.0 && guard++ < 1000) {
+            if (abs(moonPos.elevation) < 0.03) {
+                moonset = daynum
+            } else {
+                daynum += 0.004 * moonPos.elevation
                 moonPos = getMoonPosition(observer, daynumToMillis(daynum))
-            if (moonPos.elevation <= 0) moonset = daynum
             }
+        }
+        if (moonset == 0.0) moonset = daynum
 
         return RiseSetTimes(daynumToMillis(moonrise), daynumToMillis(moonset))
     }
@@ -607,7 +646,8 @@ object CelestialComputer {
         val topZ = cosLat * cosTheta * rx + cosLat * sinTheta * ry + sinLat * rz
 
         // Match north-based convention (0=N, 90=E) used by OrbitalObject.calculateObs
-        var azim = atan2(-topE, topS)
+        // Must use atan(-topE / topS) not atan2(-topE, topS) — they differ in quadrant handling
+        var azim = atan(-topE / topS)
         if (topS > 0.0) azim += PI
         if (azim < 0.0) azim += TWO_PI
         val el = asin(topZ / rMag)

gradle/libs.versions.toml

@@ -25,7 +25,7 @@ compose-navigation3 = "1.1.1"
 
 google-ksp = "2.3.6"
 
-kotlin = "2.3.20"
+kotlin = "2.3.21"
 kotlin-coroutines = "1.10.2"
 kotlin-serialization = "1.11.0"
 

gradle/wrapper/gradle-wrapper.properties

@@ -1,7 +1,7 @@
-#Sun Mar 22 10:09:53 GMT 2026
+#Tue Apr 28 15:46:23 BST 2026
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-9.4.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.5.0-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME