From 10d0c2f77c3902c8d78030497db6f50538426212 Mon Sep 17 00:00:00 2001
From: LukasK13 <spam.lukas.klass@gmail.com>
Date: Mon, 29 Jun 2020 10:41:26 +0200
Subject: [PATCH] Emissivity parameter added

---
 docs/source/configuration/optical_components.rst       |  8 +++++---
 esbo_etc/classes/optical_component/CosmicBackground.py | 10 ++++++++--
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/docs/source/configuration/optical_components.rst b/docs/source/configuration/optical_components.rst
index ff9dcbb..66790e4 100644
--- a/docs/source/configuration/optical_components.rst
+++ b/docs/source/configuration/optical_components.rst
@@ -41,13 +41,15 @@ This component allows to model generic black body noise sources like the cosmic
 
 .. code-block:: xml
 
-    <optical_component type="CosmicBackground" temp="2.7" temp_unit="K"/>
+    <optical_component type="CosmicBackground" temp="2.7" temp_unit="K" emissivity="1.0"/>
 
 Attributes:
     * | **temp:** float
-      |   The temperature of the black body.
+      | The temperature of the black body.
     * | **temp_unit:** str, *optional* = "K"
-      |   The unit of the black body's temperature. This has to be one of [``K``, ``Celsius``]. The default is ``K``.
+      | The unit of the black body's temperature. This has to be one of [``K``, ``Celsius``]. The default is ``K``.
+    * | **emissivity:** float, *optional*
+      | The emissivity of the cosmic background.
 
 Mirror
 ------
diff --git a/esbo_etc/classes/optical_component/CosmicBackground.py b/esbo_etc/classes/optical_component/CosmicBackground.py
index 36b58df..b36a7e1 100644
--- a/esbo_etc/classes/optical_component/CosmicBackground.py
+++ b/esbo_etc/classes/optical_component/CosmicBackground.py
@@ -12,7 +12,7 @@ class CosmicBackground(AOpticalComponent):
     """
 
     @u.quantity_input(temp=[u.Kelvin, u.Celsius])
-    def __init__(self, parent: IRadiant, temp: u.Quantity = 2.725 * u.K):
+    def __init__(self, parent: IRadiant, temp: u.Quantity = 2.725 * u.K, emissivity: float = 1):
         """
         Initialize a new black body point source
 
@@ -22,6 +22,8 @@ class CosmicBackground(AOpticalComponent):
             The parent element of the optical component from which the electromagnetic radiation is received
         temp : Quantity in Kelvin / Celsius
             Temperature of the black body
+        emissivity : float
+            The spectral emissivity coefficient for the optical surface.
 
         Returns
         -------
@@ -29,7 +31,7 @@ class CosmicBackground(AOpticalComponent):
         # Create black body model with given temperature
         bb = BlackBody(temperature=temp, scale=1 * u.W / (u.m ** 2 * u.nm * u.sr))
         # Initialize super class
-        super().__init__(parent, 1.0, lambda wl: bb(wl))
+        super().__init__(parent, 1.0, lambda wl: bb(wl) * emissivity)
 
     @staticmethod
     def check_config(conf: Entry) -> Union[None, str]:
@@ -49,3 +51,7 @@ class CosmicBackground(AOpticalComponent):
         mes = conf.check_quantity("temp", u.K)
         if mes is not None:
             return mes
+        if hasattr(conf, "emissivity"):
+            mes = conf.check_float("emissivity")
+            if mes is not None:
+                return mes