diff --git a/.github/workflows/build-and-test.yml b/.github/workflows/build-and-test.yml
index 653d068..d55b89f 100644
--- a/.github/workflows/build-and-test.yml
+++ b/.github/workflows/build-and-test.yml
@@ -41,3 +41,24 @@ jobs:
           CIBW_SKIP: pp*
           CIBW_TEST_COMMAND: python -m unittest discover ephem
           CIBW_TEST_REQUIRES: tzdata
+
+  twine_check:
+    name: Run twine check
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        name: Install Python
+        with:
+          python-version: '3.12'
+
+      - name: Install dependencies
+        run: python -m pip install build twine
+
+      - name: Build sdist and wheel
+        run: python -m build
+
+      - name: Run twine check
+        run: ls dist/* | xargs twine check
diff --git a/.github/workflows/github-deploy.yml b/.github/workflows/github-deploy.yml
index 5c8d0b1..f6fa787 100644
--- a/.github/workflows/github-deploy.yml
+++ b/.github/workflows/github-deploy.yml
@@ -130,10 +130,13 @@ jobs:
       - uses: actions/setup-python@v5
         name: Install Python
         with:
-          python-version: '3.8'
+          python-version: '3.12'
+
+      - name: Install dependencies
+        run: python -m pip install build
 
       - name: Build sdist
-        run: python setup.py sdist
+        run: python -m build --sdist
 
       - uses: actions/upload-artifact@v4
         with:
@@ -151,6 +154,9 @@ jobs:
           path: dist
           merge-multiple: true
 
+      - name: List files to upload
+        run: ls -1 dist/
+
       - uses: pypa/gh-action-pypi-publish@release/v1
         with:
           skip-existing: true
diff --git a/setup.py b/setup.py
index 0d44e25..186bc28 100644
--- a/setup.py
+++ b/setup.py
@@ -51,7 +51,7 @@
       version = __version__,
       description = 'Compute positions of the planets and stars',
       long_description = README,
-      #long_description_content_type = 'text/x-rst',
+      long_description_content_type = 'text/x-rst',
       license = 'MIT',
       author = 'Brandon Rhodes',
       author_email = 'brandon@rhodesmill.org',