diff --git a/app/src/main/java/com/rtbishop/look4sat/data/repository/PassesRepo.kt b/app/src/main/java/com/rtbishop/look4sat/data/repository/PassesRepo.kt
index 238a2f1f..9e6d8a06 100644
--- a/app/src/main/java/com/rtbishop/look4sat/data/repository/PassesRepo.kt
+++ b/app/src/main/java/com/rtbishop/look4sat/data/repository/PassesRepo.kt
@@ -18,7 +18,6 @@
 package com.rtbishop.look4sat.data.repository
 
 import com.github.amsacode.predict4java.Satellite
-import com.rtbishop.look4sat.data.model.Result
 import com.rtbishop.look4sat.data.model.SatPass
 import com.rtbishop.look4sat.di.DefaultDispatcher
 import com.rtbishop.look4sat.utility.PrefsManager
@@ -36,13 +35,13 @@ class PassesRepo @Inject constructor(
     private val prefsManager: PrefsManager,
     @DefaultDispatcher private val defaultDispatcher: CoroutineDispatcher
 ) {
-    private val _passes = MutableSharedFlow<Result<List<SatPass>>>(replay = 1)
+    private val _passes = MutableSharedFlow<List<SatPass>>(replay = 1)
     private var selectedSatellites = emptyList<Satellite>()
-    val passes: SharedFlow<Result<List<SatPass>>> = _passes
+    val passes: SharedFlow<List<SatPass>> = _passes
 
     suspend fun triggerCalculation(satellites: List<Satellite>, refDate: Date = Date()) {
         if (satellites.isEmpty()) {
-            _passes.emit(Result.Error(Exception()))
+            _passes.emit(emptyList())
         } else {
             val oldCatNums = selectedSatellites.map { it.tle.catnum }
             val newCatNums = satellites.map { it.tle.catnum }
@@ -52,16 +51,13 @@ class PassesRepo @Inject constructor(
 
     suspend fun forceCalculation(satellites: List<Satellite>, refDate: Date = Date()) {
         if (satellites.isEmpty()) {
-            _passes.emit(Result.Error(Exception()))
+            _passes.emit(emptyList())
         } else {
-            _passes.emit(Result.InProgress)
             withContext(defaultDispatcher) {
                 val allPasses = mutableListOf<SatPass>()
                 selectedSatellites = satellites
-                satellites.forEach { satellite ->
-                    allPasses.addAll(getPasses(satellite, refDate))
-                }
-                _passes.emit(Result.Success(filterPasses(allPasses, refDate)))
+                satellites.forEach { satellite -> allPasses.addAll(getPasses(satellite, refDate)) }
+                _passes.emit(filterPasses(allPasses, refDate))
             }
         }
     }
diff --git a/app/src/main/java/com/rtbishop/look4sat/ui/passesScreen/PassesAdapter.kt b/app/src/main/java/com/rtbishop/look4sat/ui/passesScreen/PassesAdapter.kt
index 747aa7e1..86ef53f2 100644
--- a/app/src/main/java/com/rtbishop/look4sat/ui/passesScreen/PassesAdapter.kt
+++ b/app/src/main/java/com/rtbishop/look4sat/ui/passesScreen/PassesAdapter.kt
@@ -42,30 +42,13 @@ class PassesAdapter(private val isUTC: Boolean, private val clickListener: Passe
         }
     }
     private val differ = AsyncListDiffer(this, diffCallback)
-    private var currentPasses = emptyList<SatPass>()
 
     interface PassesClickListener {
         fun navigateToPass(satPass: SatPass)
     }
 
     fun submitList(passes: List<SatPass>) {
-        currentPasses = passes
-        tickDiffer(System.currentTimeMillis())
-    }
-
-    fun tickDiffer(timeNow: Long) {
-        val copiedPasses = currentPasses.map { pass -> pass.copy() }
-        copiedPasses.forEach { pass ->
-            if (!pass.isDeepSpace) {
-                val timeStart = pass.aosDate.time
-                if (timeNow > timeStart) {
-                    val deltaNow = timeNow.minus(timeStart).toFloat()
-                    val deltaTotal = pass.losDate.time.minus(timeStart).toFloat()
-                    pass.progress = ((deltaNow / deltaTotal) * 100).toInt()
-                }
-            }
-        }
-        differ.submitList(copiedPasses.filter { pass -> pass.progress < 100 })
+        differ.submitList(passes)
     }
 
     override fun getItemCount() = differ.currentList.size
diff --git a/app/src/main/java/com/rtbishop/look4sat/ui/passesScreen/PassesFragment.kt b/app/src/main/java/com/rtbishop/look4sat/ui/passesScreen/PassesFragment.kt
index 621fd488..ffebbe52 100644
--- a/app/src/main/java/com/rtbishop/look4sat/ui/passesScreen/PassesFragment.kt
+++ b/app/src/main/java/com/rtbishop/look4sat/ui/passesScreen/PassesFragment.kt
@@ -39,7 +39,6 @@ import java.util.*
 class PassesFragment : Fragment(R.layout.fragment_passes), PassesAdapter.PassesClickListener {
 
     private val viewModel: PassesViewModel by viewModels()
-    private var passes = listOf<SatPass>()
 
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
         super.onViewCreated(view, savedInstanceState)
@@ -62,9 +61,6 @@ class PassesFragment : Fragment(R.layout.fragment_passes), PassesAdapter.PassesC
         viewModel.passes.observe(viewLifecycleOwner, { passesResult ->
             handleNewPasses(passesResult, passesAdapter, binding)
         })
-        viewModel.getAppTimer().observe(viewLifecycleOwner, { timeNow ->
-            tickMainTimer(timeNow, passesAdapter, binding)
-        })
     }
 
     private fun handleNewPasses(
@@ -74,16 +70,15 @@ class PassesFragment : Fragment(R.layout.fragment_passes), PassesAdapter.PassesC
     ) {
         when (result) {
             is Result.Success -> {
-                passes = result.data
-                passesAdapter.submitList(passes)
+                passesAdapter.submitList(result.data)
                 binding.apply {
                     passesError.visibility = View.INVISIBLE
                     passesProgress.visibility = View.INVISIBLE
                     passesRecycler.visibility = View.VISIBLE
                 }
+                tickMainTimer(result.data, binding)
             }
             is Result.InProgress -> {
-                passes = emptyList()
                 binding.apply {
                     passesTimer.text = 0L.formatForTimer()
                     passesError.visibility = View.INVISIBLE
@@ -92,7 +87,6 @@ class PassesFragment : Fragment(R.layout.fragment_passes), PassesAdapter.PassesC
                 }
             }
             is Result.Error -> {
-                passes = emptyList()
                 binding.apply {
                     passesTimer.text = 0L.formatForTimer()
                     passesProgress.visibility = View.INVISIBLE
@@ -103,12 +97,9 @@ class PassesFragment : Fragment(R.layout.fragment_passes), PassesAdapter.PassesC
         }
     }
 
-    private fun tickMainTimer(
-        timeNow: Long,
-        passesAdapter: PassesAdapter,
-        binding: FragmentPassesBinding
-    ) {
+    private fun tickMainTimer(passes: List<SatPass>, binding: FragmentPassesBinding) {
         if (passes.isNotEmpty()) {
+            val timeNow = System.currentTimeMillis()
             try {
                 val nextPass = passes.first { it.aosDate.time.minus(timeNow) > 0 }
                 val millisBeforeStart = nextPass.aosDate.time.minus(timeNow)
@@ -118,7 +109,6 @@ class PassesFragment : Fragment(R.layout.fragment_passes), PassesAdapter.PassesC
                 val millisBeforeEnd = lastPass.losDate.time.minus(timeNow)
                 binding.passesTimer.text = millisBeforeEnd.formatForTimer()
             }
-            passesAdapter.tickDiffer(timeNow)
         } else {
             binding.passesTimer.text = 0L.formatForTimer()
         }
diff --git a/app/src/main/java/com/rtbishop/look4sat/ui/passesScreen/PassesViewModel.kt b/app/src/main/java/com/rtbishop/look4sat/ui/passesScreen/PassesViewModel.kt
index 21f0d82b..7d15824e 100644
--- a/app/src/main/java/com/rtbishop/look4sat/ui/passesScreen/PassesViewModel.kt
+++ b/app/src/main/java/com/rtbishop/look4sat/ui/passesScreen/PassesViewModel.kt
@@ -17,16 +17,18 @@
  */
 package com.rtbishop.look4sat.ui.passesScreen
 
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
-import androidx.lifecycle.asLiveData
-import androidx.lifecycle.liveData
 import androidx.lifecycle.viewModelScope
+import com.rtbishop.look4sat.data.model.Result
+import com.rtbishop.look4sat.data.model.SatPass
 import com.rtbishop.look4sat.data.repository.PassesRepo
 import com.rtbishop.look4sat.data.repository.SatelliteRepo
 import com.rtbishop.look4sat.utility.PrefsManager
 import dagger.hilt.android.lifecycle.HiltViewModel
-import kotlinx.coroutines.delay
-import kotlinx.coroutines.launch
+import kotlinx.coroutines.*
+import kotlinx.coroutines.flow.collect
 import javax.inject.Inject
 
 @HiltViewModel
@@ -36,28 +38,52 @@ class PassesViewModel @Inject constructor(
     private val passesRepo: PassesRepo
 ) : ViewModel() {
 
-    val passes = passesRepo.passes.asLiveData(viewModelScope.coroutineContext)
+    private val _passes = MutableLiveData<Result<List<SatPass>>>(Result.InProgress)
+    private var passesProcessing: Job? = null
+    val passes: LiveData<Result<List<SatPass>>> = _passes
 
     init {
         viewModelScope.launch {
+            _passes.postValue(Result.InProgress)
             passesRepo.triggerCalculation(satelliteRepo.getSelectedSatellites())
         }
+        viewModelScope.launch {
+            passesRepo.passes.collect { passes ->
+                passesProcessing?.cancelAndJoin()
+                passesProcessing = viewModelScope.launch { tickPasses(passes) }
+            }
+        }
     }
 
     fun forceCalculation() {
         viewModelScope.launch {
+            _passes.postValue(Result.InProgress)
+            passesProcessing?.cancelAndJoin()
             passesRepo.forceCalculation(satelliteRepo.getSelectedSatellites())
         }
     }
 
-    fun getAppTimer() = liveData {
-        while (true) {
-            emit(System.currentTimeMillis())
-            delay(1000)
-        }
-    }
-
     fun shouldUseUTC(): Boolean {
         return prefsManager.shouldUseUTC()
     }
+
+    private suspend fun tickPasses(passes: List<SatPass>) = withContext(Dispatchers.Default) {
+        var currentPasses = passes
+        while (isActive) {
+            val timeNow = System.currentTimeMillis()
+            currentPasses.forEach { pass ->
+                if (!pass.isDeepSpace) {
+                    val timeStart = pass.aosDate.time
+                    if (timeNow > timeStart) {
+                        val deltaNow = timeNow.minus(timeStart).toFloat()
+                        val deltaTotal = pass.losDate.time.minus(timeStart).toFloat()
+                        pass.progress = ((deltaNow / deltaTotal) * 100).toInt()
+                    }
+                }
+            }
+            currentPasses = currentPasses.filter { it.progress < 100 }
+            _passes.postValue(Result.Success(currentPasses.map { it.copy() }))
+            delay(1000)
+        }
+    }
 }
diff --git a/app/src/main/java/com/rtbishop/look4sat/ui/polarScreen/PolarViewModel.kt b/app/src/main/java/com/rtbishop/look4sat/ui/polarScreen/PolarViewModel.kt
index 83ce0831..44e9dfbb 100644
--- a/app/src/main/java/com/rtbishop/look4sat/ui/polarScreen/PolarViewModel.kt
+++ b/app/src/main/java/com/rtbishop/look4sat/ui/polarScreen/PolarViewModel.kt
@@ -18,7 +18,6 @@
 package com.rtbishop.look4sat.ui.polarScreen
 
 import androidx.lifecycle.*
-import com.rtbishop.look4sat.data.model.Result
 import com.rtbishop.look4sat.data.repository.PassesRepo
 import com.rtbishop.look4sat.data.repository.SatelliteRepo
 import com.rtbishop.look4sat.utility.PrefsManager
@@ -48,10 +47,8 @@ class PolarViewModel @Inject constructor(
 
     fun getPass(catNum: Int, aosTime: Long) = liveData {
         passesRepo.passes.collect { passes ->
-            if (passes is Result.Success) {
-                val pass = passes.data.find { it.catNum == catNum && it.aosDate.time == aosTime }
-                pass?.let { emit(it) }
-            }
+            val pass = passes.find { it.catNum == catNum && it.aosDate.time == aosTime }
+            pass?.let { emit(it) }
         }
     }