diff --git a/CHANGELOG.md b/CHANGELOG.md
index 709606c..6f26b9a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## Next version
 
+### ✨ Improved
+
+* Cast NaNs in header to nulls.
+
 ### 🏷️ Changed
 
 * Disable download of IERS tables. Updated `astropy-iers-data`.
diff --git a/poetry.lock b/poetry.lock
index f800182..5edc5e8 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -2293,56 +2293,50 @@ requests = "*"
 
 [[package]]
 name = "sphinxcontrib-applehelp"
-version = "1.0.7"
+version = "1.0.8"
 description = "sphinxcontrib-applehelp is a Sphinx extension which outputs Apple help books"
 optional = false
 python-versions = ">=3.9"
 files = [
-    {file = "sphinxcontrib_applehelp-1.0.7-py3-none-any.whl", hash = "sha256:094c4d56209d1734e7d252f6e0b3ccc090bd52ee56807a5d9315b19c122ab15d"},
-    {file = "sphinxcontrib_applehelp-1.0.7.tar.gz", hash = "sha256:39fdc8d762d33b01a7d8f026a3b7d71563ea3b72787d5f00ad8465bd9d6dfbfa"},
+    {file = "sphinxcontrib_applehelp-1.0.8-py3-none-any.whl", hash = "sha256:cb61eb0ec1b61f349e5cc36b2028e9e7ca765be05e49641c97241274753067b4"},
+    {file = "sphinxcontrib_applehelp-1.0.8.tar.gz", hash = "sha256:c40a4f96f3776c4393d933412053962fac2b84f4c99a7982ba42e09576a70619"},
 ]
 
-[package.dependencies]
-Sphinx = ">=5"
-
 [package.extras]
 lint = ["docutils-stubs", "flake8", "mypy"]
+standalone = ["Sphinx (>=5)"]
 test = ["pytest"]
 
 [[package]]
 name = "sphinxcontrib-devhelp"
-version = "1.0.5"
+version = "1.0.6"
 description = "sphinxcontrib-devhelp is a sphinx extension which outputs Devhelp documents"
 optional = false
 python-versions = ">=3.9"
 files = [
-    {file = "sphinxcontrib_devhelp-1.0.5-py3-none-any.whl", hash = "sha256:fe8009aed765188f08fcaadbb3ea0d90ce8ae2d76710b7e29ea7d047177dae2f"},
-    {file = "sphinxcontrib_devhelp-1.0.5.tar.gz", hash = "sha256:63b41e0d38207ca40ebbeabcf4d8e51f76c03e78cd61abe118cf4435c73d4212"},
+    {file = "sphinxcontrib_devhelp-1.0.6-py3-none-any.whl", hash = "sha256:6485d09629944511c893fa11355bda18b742b83a2b181f9a009f7e500595c90f"},
+    {file = "sphinxcontrib_devhelp-1.0.6.tar.gz", hash = "sha256:9893fd3f90506bc4b97bdb977ceb8fbd823989f4316b28c3841ec128544372d3"},
 ]
 
-[package.dependencies]
-Sphinx = ">=5"
-
 [package.extras]
 lint = ["docutils-stubs", "flake8", "mypy"]
+standalone = ["Sphinx (>=5)"]
 test = ["pytest"]
 
 [[package]]
 name = "sphinxcontrib-htmlhelp"
-version = "2.0.4"
+version = "2.0.5"
 description = "sphinxcontrib-htmlhelp is a sphinx extension which renders HTML help files"
 optional = false
 python-versions = ">=3.9"
 files = [
-    {file = "sphinxcontrib_htmlhelp-2.0.4-py3-none-any.whl", hash = "sha256:8001661c077a73c29beaf4a79968d0726103c5605e27db92b9ebed8bab1359e9"},
-    {file = "sphinxcontrib_htmlhelp-2.0.4.tar.gz", hash = "sha256:6c26a118a05b76000738429b724a0568dbde5b72391a688577da08f11891092a"},
+    {file = "sphinxcontrib_htmlhelp-2.0.5-py3-none-any.whl", hash = "sha256:393f04f112b4d2f53d93448d4bce35842f62b307ccdc549ec1585e950bc35e04"},
+    {file = "sphinxcontrib_htmlhelp-2.0.5.tar.gz", hash = "sha256:0dc87637d5de53dd5eec3a6a01753b1ccf99494bd756aafecd74b4fa9e729015"},
 ]
 
-[package.dependencies]
-Sphinx = ">=5"
-
 [package.extras]
 lint = ["docutils-stubs", "flake8", "mypy"]
+standalone = ["Sphinx (>=5)"]
 test = ["html5lib", "pytest"]
 
 [[package]]
@@ -2361,38 +2355,34 @@ test = ["flake8", "mypy", "pytest"]
 
 [[package]]
 name = "sphinxcontrib-qthelp"
-version = "1.0.6"
+version = "1.0.7"
 description = "sphinxcontrib-qthelp is a sphinx extension which outputs QtHelp documents"
 optional = false
 python-versions = ">=3.9"
 files = [
-    {file = "sphinxcontrib_qthelp-1.0.6-py3-none-any.whl", hash = "sha256:bf76886ee7470b934e363da7a954ea2825650013d367728588732c7350f49ea4"},
-    {file = "sphinxcontrib_qthelp-1.0.6.tar.gz", hash = "sha256:62b9d1a186ab7f5ee3356d906f648cacb7a6bdb94d201ee7adf26db55092982d"},
+    {file = "sphinxcontrib_qthelp-1.0.7-py3-none-any.whl", hash = "sha256:e2ae3b5c492d58fcbd73281fbd27e34b8393ec34a073c792642cd8e529288182"},
+    {file = "sphinxcontrib_qthelp-1.0.7.tar.gz", hash = "sha256:053dedc38823a80a7209a80860b16b722e9e0209e32fea98c90e4e6624588ed6"},
 ]
 
-[package.dependencies]
-Sphinx = ">=5"
-
 [package.extras]
 lint = ["docutils-stubs", "flake8", "mypy"]
+standalone = ["Sphinx (>=5)"]
 test = ["pytest"]
 
 [[package]]
 name = "sphinxcontrib-serializinghtml"
-version = "1.1.9"
+version = "1.1.10"
 description = "sphinxcontrib-serializinghtml is a sphinx extension which outputs \"serialized\" HTML files (json and pickle)"
 optional = false
 python-versions = ">=3.9"
 files = [
-    {file = "sphinxcontrib_serializinghtml-1.1.9-py3-none-any.whl", hash = "sha256:9b36e503703ff04f20e9675771df105e58aa029cfcbc23b8ed716019b7416ae1"},
-    {file = "sphinxcontrib_serializinghtml-1.1.9.tar.gz", hash = "sha256:0c64ff898339e1fac29abd2bf5f11078f3ec413cfe9c046d3120d7ca65530b54"},
+    {file = "sphinxcontrib_serializinghtml-1.1.10-py3-none-any.whl", hash = "sha256:326369b8df80a7d2d8d7f99aa5ac577f51ea51556ed974e7716cfd4fca3f6cb7"},
+    {file = "sphinxcontrib_serializinghtml-1.1.10.tar.gz", hash = "sha256:93f3f5dc458b91b192fe10c397e324f262cf163d79f3282c158e8436a2c4511f"},
 ]
 
-[package.dependencies]
-Sphinx = ">=5"
-
 [package.extras]
 lint = ["docutils-stubs", "flake8", "mypy"]
+standalone = ["Sphinx (>=5)"]
 test = ["pytest"]
 
 [[package]]
diff --git a/pyproject.toml b/pyproject.toml
index 713f9f7..9ff9d0f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "sdss-lvmscp"
-version = "0.8.1a0"
+version = "0.8.1"
 description = "LVM spectrograph control package."
 authors = ["José Sánchez-Gallego <gallegoj@uw.edu>", "Changgon Kim <changgonkim@khu.ac.kr>"]
 maintainers = ["José Sánchez-Gallego <gallegoj@uw.edu>"]