diff --git a/aastex/_aastex.py b/aastex/_aastex.py
index be07d45..9dd9add 100644
--- a/aastex/_aastex.py
+++ b/aastex/_aastex.py
@@ -140,11 +140,39 @@ def affiliations(self) -> list[Affiliation]:
 
 @dataclasses.dataclass
 class Acronym(pylatex.base_classes.LatexObject):
+    r"""
+    An acronym which is expanded on first use and abbreviated thereafter.
+
+    Defining an acronym also defines LaTeX commands for using it:
+    ``\NASA`` expands it on first use and abbreviates it afterwards, and
+    ``\NASACapital`` does the same with the first letter capitalized, for a
+    sentence which begins with the acronym.
+    The capitalized form matters for an instrument whose name reads as
+    ``"the Multi-slit Solar Explorer"``, since a sentence should open with
+    "The" rather than "the".
+    ``\NASAs`` and ``\NASACapitals`` are the plural forms, and ``\NASAShort``
+    is the abbreviation whether or not it has been used before.
+    """
+
     acronym: str
+    """The abbreviated form of this acronym."""
+
     name_full: str
+    """
+    The expanded form of this acronym.
+
+    Include a leading article, as in ``"the Multi-slit Solar Explorer"``,
+    for a name which needs one.
+    """
+
     name_short: None | str = None
+    """The abbreviation to display, if it differs from :attr:`acronym`."""
+
     plural: bool = False
+    """Whether to define the plural forms of this acronym."""
+
     short: bool = False
+    """Whether to define a command which always gives the abbreviation."""
 
     def __post_init__(self):
         self.packages.append(pylatex.Package("acronym"))
@@ -187,6 +215,21 @@ def dumps(self):
                     pylatex.NoEscape(rf"\acs{{{self.acronym}}}"),
                 ],
             ).dumps()
+        command += pylatex.Command(
+            command="newcommand",
+            arguments=[
+                pylatex.NoEscape(rf"\{self.acronym}Capital"),
+                pylatex.NoEscape(rf"\Ac{{{self.acronym}}}"),
+            ],
+        ).dumps()
+        if self.plural:
+            command += pylatex.Command(
+                command="newcommand",
+                arguments=[
+                    pylatex.NoEscape(rf"\{self.acronym}Capitals"),
+                    pylatex.NoEscape(rf"\Acp{{{self.acronym}}}"),
+                ],
+            ).dumps()
         return command
 
 
diff --git a/aastex/_tests/test_aastex.py b/aastex/_tests/test_aastex.py
index 93d4b04..f1ba785 100644
--- a/aastex/_tests/test_aastex.py
+++ b/aastex/_tests/test_aastex.py
@@ -144,6 +144,52 @@ def test_short(self, a: aastex.Acronym):
     def test_dumps(self, a: aastex.Title):
         assert isinstance(a.dumps(), str)
 
+    def test_capital(self, a: aastex.Acronym):
+        """A capitalized command is defined for a sentence starting with the acronym."""
+        dumps = a.dumps()
+        assert rf"\{a.acronym}Capital" in dumps
+        assert rf"\Ac{{{a.acronym}}}" in dumps
+        if a.plural:
+            assert rf"\{a.acronym}Capitals" in dumps
+            assert rf"\Acp{{{a.acronym}}}" in dumps
+
+
+@pytest.mark.skipif(
+    shutil.which("latexmk") is None,
+    reason="requires a LaTeX installation",
+)
+def test_acronym_capital_compiles(tmp_path: pathlib.Path):
+    """
+    The capitalized command raises the article of a name which carries one.
+
+    An instrument named "the Multi-slit Solar Explorer" should open a sentence
+    with "The", which is what the underlying `acronym` package provides.
+    """
+    doc = aastex.Document(document_options="twocolumn", linenumbers=False)
+    doc.preamble.append(aastex.Acronym("MUSE", "the Multi-slit Solar Explorer"))
+    doc.append(aastex.Title("Acronyms"))
+    doc += [
+        aastex.Author(
+            name="Jane Doe",
+            affiliation=aastex.Affiliation("Fancy University"),
+        )
+    ]
+    section = aastex.Section("Introduction")
+    section.append(pylatex.NoEscape(r"\MUSECapital\ observes the Sun. \MUSE\ again."))
+    doc.append(section)
+
+    path = tmp_path / "acronyms"
+    doc.generate_pdf(path, clean_tex=False)
+
+    text = subprocess.run(
+        args=["pdftotext", str(path.with_suffix(".pdf")), "-"],
+        capture_output=True,
+        text=True,
+    ).stdout
+
+    assert "The Multi-slit Solar Explorer (MUSE)" in text
+    assert "MUSE again" in text
+
 
 @pytest.mark.parametrize(
     argnames="a",