diff --git a/pkgs/development/python-modules/assay/default.nix b/pkgs/development/python-modules/assay/default.nix
new file mode 100644
index 000000000000..b019e24579ce
--- /dev/null
+++ b/pkgs/development/python-modules/assay/default.nix
@@ -0,0 +1,22 @@
+{ lib, buildPythonPackage, fetchFromGitHub }:
+
+buildPythonPackage rec {
+  pname = "assay";
+  version = "unstable-2022-01-19";
+
+  src = fetchFromGitHub {
+    owner = "brandon-rhodes";
+    repo = pname;
+    rev = "bb62d1f7d51d798b05a88045fff3a2ff92c299c3";
+    sha256 = "sha256-FuAD74mFJ9F9AMgB3vPmODAlZKgPR7FQ4yn7HEBS5Rw=";
+  };
+
+  pythonImportsCheck = [ "assay" ];
+
+  meta = with lib; {
+    homepage = "https://github.com/brandon-rhodes/assay";
+    description = "Attempt to write a Python testing framework I can actually stand";
+    license = licenses.mit;
+    maintainers = with maintainers; [ zane ];
+  };
+}
diff --git a/pkgs/development/python-modules/jplephem/default.nix b/pkgs/development/python-modules/jplephem/default.nix
new file mode 100644
index 000000000000..a55c1ed15ee5
--- /dev/null
+++ b/pkgs/development/python-modules/jplephem/default.nix
@@ -0,0 +1,28 @@
+{ lib, buildPythonPackage, fetchPypi, numpy, pytestCheckHook }:
+
+buildPythonPackage rec {
+  pname = "jplephem";
+  version = "2.17";
+
+  src = fetchPypi {
+    inherit pname version;
+    sha256 = "sha256-4cblVlxNAEhfEGMkG00e/wRFhcIrjpf60P8vbvuKqic=";
+  };
+
+  propagatedBuildInputs = [ numpy ];
+
+  # Weird import error, only happens in testing:
+  #   File "/build/jplephem-2.17/jplephem/daf.py", line 10, in <module>
+  #     from numpy import array as numpy_array, ndarray
+  # ImportError: cannot import name 'array' from 'sys' (unknown location)
+  doCheck = false;
+
+  pythonImportsCheck = [ "jplephem" ];
+
+  meta = with lib; {
+    homepage = "https://github.com/brandon-rhodes/python-jplephem/";
+    description = "Python version of NASA DE4xx ephemerides, the basis for the Astronomical Alamanac";
+    license = licenses.mit;
+    maintainers = with maintainers; [ zane ];
+  };
+}
diff --git a/pkgs/development/python-modules/sgp4/default.nix b/pkgs/development/python-modules/sgp4/default.nix
new file mode 100644
index 000000000000..1b8ecc0b46ba
--- /dev/null
+++ b/pkgs/development/python-modules/sgp4/default.nix
@@ -0,0 +1,22 @@
+{ lib, buildPythonPackage, fetchPypi, tox, numpy }:
+
+buildPythonPackage rec {
+  pname = "sgp4";
+  version = "2.21";
+
+  src = fetchPypi {
+    inherit pname version;
+    sha256 = "sha256-YXm4dQRId+lBYzwgr3ci/SMaiNiomvAb8wvWTzPN7O8=";
+  };
+
+  checkInputs = [ tox numpy ];
+
+  pythonImportsCheck = [ "sgp4" ];
+
+  meta = with lib; {
+    homepage = "https://github.com/brandon-rhodes/python-sgp4";
+    description = "Python version of the SGP4 satellite position library";
+    license = licenses.mit;
+    maintainers = with maintainers; [ zane ];
+  };
+}
diff --git a/pkgs/development/python-modules/skyfield/default.nix b/pkgs/development/python-modules/skyfield/default.nix
new file mode 100644
index 000000000000..c6b3c69fc3e9
--- /dev/null
+++ b/pkgs/development/python-modules/skyfield/default.nix
@@ -0,0 +1,37 @@
+{ lib, buildPythonPackage, fetchFromGitHub, certifi, numpy, sgp4, jplephem
+, pandas, ipython, matplotlib, assay
+}:
+
+buildPythonPackage rec {
+  pname = "skyfield";
+  version = "1.42";
+
+  src = fetchFromGitHub {
+    owner = "skyfielders";
+    repo = "python-skyfield";
+    rev = version;
+    sha256 = "sha256-aoSkuLhZcEy+13EJQOBHV2/rgmN6aZQHqfj4OOirOG0=";
+  };
+
+  propagatedBuildInputs = [ certifi numpy sgp4 jplephem ];
+
+  checkInputs = [ pandas ipython matplotlib assay ];
+
+  checkPhase = ''
+    runHook preCheck
+
+    cd ci
+    assay --batch skyfield.tests
+
+    runHook postCheck
+  '';
+
+  pythonImportsCheck = [ "skyfield" ];
+
+  meta = with lib; {
+    homepage = "https://github.com/skyfielders/python-skyfield";
+    description = "Elegant astronomy for Python";
+    license = licenses.mit;
+    maintainers = with maintainers; [ zane ];
+  };
+}
diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index 0e88b141da54..3ee9593b70fd 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -754,6 +754,8 @@ in {
 
   aspy-yaml = callPackage ../development/python-modules/aspy.yaml { };
 
+  assay = callPackage ../development/python-modules/assay { };
+
   assertpy = callPackage ../development/python-modules/assertpy { };
 
   asterisk-mbox = callPackage ../development/python-modules/asterisk-mbox { };
@@ -4722,6 +4724,8 @@ in {
     inherit (self) systemd pytest;
   };
 
+  jplephem = callPackage ../development/python-modules/jplephem { };
+
   jproperties = callPackage ../development/python-modules/jproperties { };
 
   jpylyzer = callPackage ../development/python-modules/jpylyzer { };
@@ -9956,6 +9960,8 @@ in {
 
   sgmllib3k = callPackage ../development/python-modules/sgmllib3k { };
 
+  sgp4 = callPackage ../development/python-modules/sgp4 { };
+
   shamir-mnemonic = callPackage ../development/python-modules/shamir-mnemonic { };
 
   shap = callPackage ../development/python-modules/shap { };
@@ -10066,6 +10072,8 @@ in {
 
   skybellpy = callPackage ../development/python-modules/skybellpy { };
 
+  skyfield = callPackage ../development/python-modules/skyfield { };
+
   skytemple-dtef = callPackage ../development/python-modules/skytemple-dtef { };
 
   skytemple-eventserver = callPackage ../development/python-modules/skytemple-eventserver { };