diff --git a/docs/source/install_for_dev.rst b/docs/source/install_for_dev.rst
index e00c97d..772d2cf 100644
--- a/docs/source/install_for_dev.rst
+++ b/docs/source/install_for_dev.rst
@@ -48,7 +48,7 @@ Then, in the Powershell terminal:
 
 	cd C:\Users\xxx\Documents\guitastro\install
 	pip install pip-tools --user
-	python -m piptools compile requirements.in	--user
+	python -m piptools compile requirements.in --user
 	python -m pip install -r requirements.txt --user
 
 3. Import guitastro from everywhere
diff --git a/src/guitastro/ephemeris.py b/src/guitastro/ephemeris.py
index 6adad99..4f3f7e8 100644
--- a/src/guitastro/ephemeris.py
+++ b/src/guitastro/ephemeris.py
@@ -1075,7 +1075,8 @@ class Ephemeris(EphemerisException, GuitastroTools):
 
                 * horizon: An object of the class Horizon of Guitastro that defines the horizon line.
                 * preference: A string "bestelev" or "immediate" to compute the visibility
-                * duskelev: A float, the elevation of the Sun defining the start and end of the night.
+                * duskelev: A float, the elevation of the Sun defining the start of the night.
+                * dawnelev: A float, the elevation of the Sun defining the end of the night.
                 * wavelength_nm: A float, the observation wavelength (in nanometers)
                 * humidity: A float, the relative humidiy (between 0 and 1)
                 * distmin_sun: A float to define the minimum angular distance from the Sun (degrees)
@@ -1145,10 +1146,17 @@ class Ephemeris(EphemerisException, GuitastroTools):
             preference = kwargs['preference'].lower()
         else:
             preference="bestelev"
-        if 'duskelev' in kwargs.keys():
+        duskelev= -7
+        dawnelev = duskelev
+        if 'duskelev' in kwargs.keys() and 'dawnelev' not in kwargs.keys():
             duskelev = kwargs['duskelev']
-        else:
-            duskelev = -7
+            dawnelev = duskelev
+        elif 'duskelev' not in kwargs.keys() and 'dawnelev' in kwargs.keys():
+            dawnelev = kwargs['dawnelev']
+            duskelev = dawnelev
+        elif 'duskelev' in kwargs.keys() and 'dawnelev' in kwargs.keys():
+            duskelev = kwargs['duskelev']
+            dawnelev = kwargs['dawnelev']
         if 'humidity' in kwargs.keys():
             rel_humidity = kwargs['humidity']
         else:
@@ -1379,6 +1387,7 @@ class Ephemeris(EphemerisException, GuitastroTools):
         horizons = np.zeros(nsec)
         # --- visibility_flag
         kk = 0
+        nsec_midnight = nsec / 2
         for alt, az in zip(alts, azs):
             k = int(np.floor(az))%360
             altmini = hor_elev[k]
@@ -1386,8 +1395,12 @@ class Ephemeris(EphemerisException, GuitastroTools):
             if alt < altmini:
                 visibility_flags[kk] += 1
             if sunmoon == True:
-                if ephem_sun['alt'][kk] > duskelev:
-                    visibility_flags[kk] += 2
+                if kk < nsec_midnight:
+                    if ephem_sun['alt'][kk] > duskelev:
+                        visibility_flags[kk] += 2
+                else:
+                    if ephem_sun['alt'][kk] > dawnelev:
+                        visibility_flags[kk] += 2
             kk += 1
         visibility_flags = np.where(distsuns > distmin_sun, visibility_flags, visibility_flags+4)
         visibility_flags = np.where(distmoons > distmin_moon, visibility_flags, visibility_flags+8)
--
libgit2 0.21.2