diff --git a/02-coords.html b/02-coords.html
index 16a16a9d..597946ab 100644
--- a/02-coords.html
+++ b/02-coords.html
@@ -469,7 +469,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb13">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -586,7 +586,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb19">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -766,7 +766,7 @@ <h3 class="callout-title">Exercise (10 minutes)<a class="anchor" aria-label="anc
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb29">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
diff --git a/03-transform.html b/03-transform.html
index 250d5380..cf2d193f 100644
--- a/03-transform.html
+++ b/03-transform.html
@@ -361,7 +361,7 @@ <h3 class="callout-title">Starting from this episode<a class="anchor" aria-label
   <h3 class="accordion-header" id="headingSpoiler1">
 <div class="note-square"><i aria-hidden="true" class="callout-icon" data-feather="eye"></i></div>Read me</h3>
 </button>
-<div id="collapseSpoiler1" class="accordion-collapse collapse" aria-labelledby="headingSpoiler1" data-bs-parent="#accordionSpoiler1">
+<div id="collapseSpoiler1" class="accordion-collapse collapse" data-bs-parent="#accordionSpoiler1" aria-labelledby="headingSpoiler1">
 <div class="accordion-body">
 <p>In the previous episode, we ran a query on the Gaia server,
 downloaded data for roughly 140,000 stars, and saved the data in a FITS
@@ -635,7 +635,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb23">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
diff --git a/06-join.html b/06-join.html
index 4c6f4c49..6b7b0f30 100644
--- a/06-join.html
+++ b/06-join.html
@@ -367,7 +367,7 @@ <h3 class="callout-title">Starting from this episode<a class="anchor" aria-label
   <h3 class="accordion-header" id="headingSpoiler1">
 <div class="note-square"><i aria-hidden="true" class="callout-icon" data-feather="eye"></i></div>Read me</h3>
 </button>
-<div id="collapseSpoiler1" class="accordion-collapse collapse" aria-labelledby="headingSpoiler1" data-bs-parent="#accordionSpoiler1">
+<div id="collapseSpoiler1" class="accordion-collapse collapse" data-bs-parent="#accordionSpoiler1" aria-labelledby="headingSpoiler1">
 <div class="accordion-body">
 <p>In the previous episode, we define a rectangle around stars in GD-1
 in spatial coordinates and in proper motion which we transformed into
@@ -1011,7 +1011,7 @@ <h3 class="callout-title">Exercise (15 minutes)<a class="anchor" aria-label="anc
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb45">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -1178,7 +1178,7 @@ <h3 class="callout-title">Exercise (15 minutes)<a class="anchor" aria-label="anc
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb54">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
diff --git a/07-photo.html b/07-photo.html
index 7503deb2..b49ad066 100644
--- a/07-photo.html
+++ b/07-photo.html
@@ -447,11 +447,12 @@ <h3 class="accordion-header" id="headingSpoiler2">
 headlights as they approach). Dust will remove light from the star’s
 path to our telescopes, which makes the star seem like it has less
 energy than it otherwise would have, which makes it do two things on
-this diagram: 1) look fainter (lower y-axis value) and 2) look cooler
-(higher x-axis value). The stars spread throughout the diagram are all
-stars bright enough to be detected in our Milky Way between GD-1 and us
-but made fainter and redder (spread to the lower-right) by their spread
-in distance from us and the amount dust in the line of sight.</p>
+this diagram: 1) look fainter (lower on the y-axis; larger magnitude
+value) and 2) look cooler (higher x-axis value). The stars spread
+throughout the diagram are all stars bright enough to be detected in our
+Milky Way between GD-1 and us but made fainter and redder (spread to the
+lower-right) by their spread in distance from us and the amount dust in
+the line of sight.</p>
 <p>GD-1: The pile up of stars in the lower-left quadrant of this diagram
 are interesting because it suggests something is at the same distance
 with the same amount of dust in the way. When we use our knowledge of
diff --git a/08-plot.html b/08-plot.html
index a82e1351..65ed3f87 100644
--- a/08-plot.html
+++ b/08-plot.html
@@ -361,7 +361,7 @@ <h3 class="callout-title">Starting from this episode<a class="anchor" aria-label
   <h3 class="accordion-header" id="headingSpoiler1">
 <div class="note-square"><i aria-hidden="true" class="callout-icon" data-feather="eye"></i></div>Read me</h3>
 </button>
-<div id="collapseSpoiler1" class="accordion-collapse collapse" aria-labelledby="headingSpoiler1" data-bs-parent="#accordionSpoiler1">
+<div id="collapseSpoiler1" class="accordion-collapse collapse" data-bs-parent="#accordionSpoiler1" aria-labelledby="headingSpoiler1">
 <div class="accordion-body">
 <p>In the previous episode, we selected stars in GD-1 based on proper
 motion and downloaded the spatial, proper motion, and photometry
@@ -455,7 +455,7 @@ <h3 class="callout-title">Exercise (10 minutes)<a class="anchor" aria-label="anc
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p>No figure is perfect, and everyone can be a critic. Here are some
 topics that could come up in this discussion:</p>
@@ -530,7 +530,7 @@ <h3 class="callout-title">Exercise (20 minutes)<a class="anchor" aria-label="anc
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb4">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -656,7 +656,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb7">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -713,7 +713,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb11">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -834,7 +834,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution5" aria-expanded="false" aria-controls="collapseSolution5">
   <h4 class="accordion-header" id="headingSolution5">Show me the solution</h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb17">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -953,7 +953,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution6" aria-expanded="false" aria-controls="collapseSolution6">
   <h4 class="accordion-header" id="headingSolution6">Show me the solution</h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <p>Without <code>tight_layout</code> the space between the panels is too
 small. In this situation, the titles from the lower plots overlap with
@@ -1020,7 +1020,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution7" aria-expanded="false" aria-controls="collapseSolution7">
   <h4 class="accordion-header" id="headingSolution7">Show me the solution</h4>
 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
+<div id="collapseSolution7" class="accordion-collapse collapse" data-bs-parent="#accordionSolution7" aria-labelledby="headingSolution7">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb24">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -1148,7 +1148,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution8" aria-expanded="false" aria-controls="collapseSolution8">
   <h4 class="accordion-header" id="headingSolution8">Show me the solution</h4>
 </button>
-<div id="collapseSolution8" class="accordion-collapse collapse" aria-labelledby="headingSolution8" data-bs-parent="#accordionSolution8">
+<div id="collapseSolution8" class="accordion-collapse collapse" data-bs-parent="#accordionSolution8" aria-labelledby="headingSolution8">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb32">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -1181,7 +1181,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution9" aria-expanded="false" aria-controls="collapseSolution9">
   <h4 class="accordion-header" id="headingSolution9">Show me the solution</h4>
 </button>
-<div id="collapseSolution9" class="accordion-collapse collapse" aria-labelledby="headingSolution9" data-bs-parent="#accordionSolution9">
+<div id="collapseSolution9" class="accordion-collapse collapse" data-bs-parent="#accordionSolution9" aria-labelledby="headingSolution9">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb33">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
diff --git a/aio.html b/aio.html
index ce1b2a02..3efc62fd 100644
--- a/aio.html
+++ b/aio.html
@@ -1573,7 +1573,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb13">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -1693,7 +1693,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb19">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -1880,7 +1880,7 @@ <h3 class="callout-title">Exercise (10 minutes)<a class="anchor" aria-label="anc
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb29">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -2391,7 +2391,7 @@ <h3 class="callout-title">Starting from this episode<a class="anchor" aria-label
   <h3 class="accordion-header" id="headingSpoiler1">
 <div class="note-square"><i aria-hidden="true" class="callout-icon" data-feather="eye"></i></div>Read me</h3>
 </button>
-<div id="collapseSpoiler1" class="accordion-collapse collapse" aria-labelledby="headingSpoiler1" data-bs-parent="#accordionSpoiler1">
+<div id="collapseSpoiler1" class="accordion-collapse collapse" data-bs-parent="#accordionSpoiler1" aria-labelledby="headingSpoiler1">
 <div class="accordion-body">
 <p>In the previous episode, we ran a query on the Gaia server,
 downloaded data for roughly 140,000 stars, and saved the data in a FITS
@@ -2670,7 +2670,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb23">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -4654,7 +4654,7 @@ <h3 class="callout-title">Starting from this episode<a class="anchor" aria-label
   <h3 class="accordion-header" id="headingSpoiler1">
 <div class="note-square"><i aria-hidden="true" class="callout-icon" data-feather="eye"></i></div>Read me</h3>
 </button>
-<div id="collapseSpoiler1" class="accordion-collapse collapse" aria-labelledby="headingSpoiler1" data-bs-parent="#accordionSpoiler1">
+<div id="collapseSpoiler1" class="accordion-collapse collapse" data-bs-parent="#accordionSpoiler1" aria-labelledby="headingSpoiler1">
 <div class="accordion-body">
 <p>In the previous episode, we define a rectangle around stars in GD-1
 in spatial coordinates and in proper motion which we transformed into
@@ -5319,7 +5319,7 @@ <h3 class="callout-title">Exercise (15 minutes)<a class="anchor" aria-label="anc
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb45">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -5487,7 +5487,7 @@ <h3 class="callout-title">Exercise (15 minutes)<a class="anchor" aria-label="anc
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
   <h4 class="accordion-header" id="headingSolution2">Show me the solution</h4>
 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb54">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -5966,11 +5966,12 @@ <h3 class="accordion-header" id="headingSpoiler2">
 headlights as they approach). Dust will remove light from the star’s
 path to our telescopes, which makes the star seem like it has less
 energy than it otherwise would have, which makes it do two things on
-this diagram: 1) look fainter (lower y-axis value) and 2) look cooler
-(higher x-axis value). The stars spread throughout the diagram are all
-stars bright enough to be detected in our Milky Way between GD-1 and us
-but made fainter and redder (spread to the lower-right) by their spread
-in distance from us and the amount dust in the line of sight.</p>
+this diagram: 1) look fainter (lower on the y-axis; larger magnitude
+value) and 2) look cooler (higher x-axis value). The stars spread
+throughout the diagram are all stars bright enough to be detected in our
+Milky Way between GD-1 and us but made fainter and redder (spread to the
+lower-right) by their spread in distance from us and the amount dust in
+the line of sight.</p>
 <p>GD-1: The pile up of stars in the lower-left quadrant of this diagram
 are interesting because it suggests something is at the same distance
 with the same amount of dust in the way. When we use our knowledge of
@@ -6686,7 +6687,7 @@ <h3 class="callout-title">Starting from this episode<a class="anchor" aria-label
   <h3 class="accordion-header" id="headingSpoiler1">
 <div class="note-square"><i aria-hidden="true" class="callout-icon" data-feather="eye"></i></div>Read me</h3>
 </button>
-<div id="collapseSpoiler1" class="accordion-collapse collapse" aria-labelledby="headingSpoiler1" data-bs-parent="#accordionSpoiler1">
+<div id="collapseSpoiler1" class="accordion-collapse collapse" data-bs-parent="#accordionSpoiler1" aria-labelledby="headingSpoiler1">
 <div class="accordion-body">
 <p>In the previous episode, we selected stars in GD-1 based on proper
 motion and downloaded the spatial, proper motion, and photometry
@@ -6785,7 +6786,7 @@ <h3 class="callout-title">Exercise (10 minutes)<a class="anchor" aria-label="anc
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-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
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 <div class="accordion-body">
 <p>No figure is perfect, and everyone can be a critic. Here are some
 topics that could come up in this discussion:</p>
@@ -6867,7 +6868,7 @@ <h3 class="callout-title">Exercise (20 minutes)<a class="anchor" aria-label="anc
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-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
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 <div class="accordion-body">
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@@ -6998,7 +6999,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
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   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
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 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
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   <h4 class="accordion-header" id="headingSolution5">Show me the solution</h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
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@@ -7299,7 +7300,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
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   <h4 class="accordion-header" id="headingSolution6">Show me the solution</h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <p>Without <code>tight_layout</code> the space between the panels is too
 small. In this situation, the titles from the lower plots overlap with
@@ -7367,7 +7368,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
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 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
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 </button>
-<div id="collapseSolution8" class="accordion-collapse collapse" aria-labelledby="headingSolution8" data-bs-parent="#accordionSolution8">
+<div id="collapseSolution8" class="accordion-collapse collapse" data-bs-parent="#accordionSolution8" aria-labelledby="headingSolution8">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb32">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
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 </button>
-<div id="collapseSolution9" class="accordion-collapse collapse" aria-labelledby="headingSolution9" data-bs-parent="#accordionSolution9">
+<div id="collapseSolution9" class="accordion-collapse collapse" data-bs-parent="#accordionSolution9" aria-labelledby="headingSolution9">
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diff --git a/instructor/02-coords.html b/instructor/02-coords.html
index c3b00b27..693b4b6d 100644
--- a/instructor/02-coords.html
+++ b/instructor/02-coords.html
@@ -471,7 +471,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
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   <h4 class="accordion-header" id="headingSolution1">Show me the solution</h4>
 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb13">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -588,7 +588,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
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 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
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 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
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 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
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diff --git a/instructor/03-transform.html b/instructor/03-transform.html
index 2d64feef..2e16fd3d 100644
--- a/instructor/03-transform.html
+++ b/instructor/03-transform.html
@@ -363,7 +363,7 @@ <h3 class="callout-title">Starting from this episode<a class="anchor" aria-label
   <h3 class="accordion-header" id="headingSpoiler1">
 <div class="note-square"><i aria-hidden="true" class="callout-icon" data-feather="eye"></i></div>Read me</h3>
 </button>
-<div id="collapseSpoiler1" class="accordion-collapse collapse" aria-labelledby="headingSpoiler1" data-bs-parent="#accordionSpoiler1">
+<div id="collapseSpoiler1" class="accordion-collapse collapse" data-bs-parent="#accordionSpoiler1" aria-labelledby="headingSpoiler1">
 <div class="accordion-body">
 <p>In the previous episode, we ran a query on the Gaia server,
 downloaded data for roughly 140,000 stars, and saved the data in a FITS
@@ -637,7 +637,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
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 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
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diff --git a/instructor/06-join.html b/instructor/06-join.html
index cb98fd7c..8bd96035 100644
--- a/instructor/06-join.html
+++ b/instructor/06-join.html
@@ -369,7 +369,7 @@ <h3 class="callout-title">Starting from this episode<a class="anchor" aria-label
   <h3 class="accordion-header" id="headingSpoiler1">
 <div class="note-square"><i aria-hidden="true" class="callout-icon" data-feather="eye"></i></div>Read me</h3>
 </button>
-<div id="collapseSpoiler1" class="accordion-collapse collapse" aria-labelledby="headingSpoiler1" data-bs-parent="#accordionSpoiler1">
+<div id="collapseSpoiler1" class="accordion-collapse collapse" data-bs-parent="#accordionSpoiler1" aria-labelledby="headingSpoiler1">
 <div class="accordion-body">
 <p>In the previous episode, we define a rectangle around stars in GD-1
 in spatial coordinates and in proper motion which we transformed into
@@ -1013,7 +1013,7 @@ <h3 class="callout-title">Exercise (15 minutes)<a class="anchor" aria-label="anc
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 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
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 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
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diff --git a/instructor/07-photo.html b/instructor/07-photo.html
index 608fbb9e..e931559c 100644
--- a/instructor/07-photo.html
+++ b/instructor/07-photo.html
@@ -449,11 +449,12 @@ <h3 class="accordion-header" id="headingSpoiler2">
 headlights as they approach). Dust will remove light from the star’s
 path to our telescopes, which makes the star seem like it has less
 energy than it otherwise would have, which makes it do two things on
-this diagram: 1) look fainter (lower y-axis value) and 2) look cooler
-(higher x-axis value). The stars spread throughout the diagram are all
-stars bright enough to be detected in our Milky Way between GD-1 and us
-but made fainter and redder (spread to the lower-right) by their spread
-in distance from us and the amount dust in the line of sight.</p>
+this diagram: 1) look fainter (lower on the y-axis; larger magnitude
+value) and 2) look cooler (higher x-axis value). The stars spread
+throughout the diagram are all stars bright enough to be detected in our
+Milky Way between GD-1 and us but made fainter and redder (spread to the
+lower-right) by their spread in distance from us and the amount dust in
+the line of sight.</p>
 <p>GD-1: The pile up of stars in the lower-left quadrant of this diagram
 are interesting because it suggests something is at the same distance
 with the same amount of dust in the way. When we use our knowledge of
diff --git a/instructor/08-plot.html b/instructor/08-plot.html
index 8bdd3e0a..3340192a 100644
--- a/instructor/08-plot.html
+++ b/instructor/08-plot.html
@@ -363,7 +363,7 @@ <h3 class="callout-title">Starting from this episode<a class="anchor" aria-label
   <h3 class="accordion-header" id="headingSpoiler1">
 <div class="note-square"><i aria-hidden="true" class="callout-icon" data-feather="eye"></i></div>Read me</h3>
 </button>
-<div id="collapseSpoiler1" class="accordion-collapse collapse" aria-labelledby="headingSpoiler1" data-bs-parent="#accordionSpoiler1">
+<div id="collapseSpoiler1" class="accordion-collapse collapse" data-bs-parent="#accordionSpoiler1" aria-labelledby="headingSpoiler1">
 <div class="accordion-body">
 <p>In the previous episode, we selected stars in GD-1 based on proper
 motion and downloaded the spatial, proper motion, and photometry
@@ -457,7 +457,7 @@ <h3 class="callout-title">Exercise (10 minutes)<a class="anchor" aria-label="anc
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
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 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p>No figure is perfect, and everyone can be a critic. Here are some
 topics that could come up in this discussion:</p>
@@ -532,7 +532,7 @@ <h3 class="callout-title">Exercise (20 minutes)<a class="anchor" aria-label="anc
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-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
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@@ -658,7 +658,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
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 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
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@@ -715,7 +715,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
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 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
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 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
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   <h4 class="accordion-header" id="headingSolution6">Show me the solution</h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <p>Without <code>tight_layout</code> the space between the panels is too
 small. In this situation, the titles from the lower plots overlap with
@@ -1022,7 +1022,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution7" aria-expanded="false" aria-controls="collapseSolution7">
   <h4 class="accordion-header" id="headingSolution7">Show me the solution</h4>
 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
+<div id="collapseSolution7" class="accordion-collapse collapse" data-bs-parent="#accordionSolution7" aria-labelledby="headingSolution7">
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 <div class="codewrapper sourceCode" id="cb24">
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@@ -1150,7 +1150,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
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 </button>
-<div id="collapseSolution8" class="accordion-collapse collapse" aria-labelledby="headingSolution8" data-bs-parent="#accordionSolution8">
+<div id="collapseSolution8" class="accordion-collapse collapse" data-bs-parent="#accordionSolution8" aria-labelledby="headingSolution8">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb32">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -1183,7 +1183,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution9" aria-expanded="false" aria-controls="collapseSolution9">
   <h4 class="accordion-header" id="headingSolution9">Show me the solution</h4>
 </button>
-<div id="collapseSolution9" class="accordion-collapse collapse" aria-labelledby="headingSolution9" data-bs-parent="#accordionSolution9">
+<div id="collapseSolution9" class="accordion-collapse collapse" data-bs-parent="#accordionSolution9" aria-labelledby="headingSolution9">
 <div class="accordion-body">
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 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
diff --git a/instructor/aio.html b/instructor/aio.html
index 37692964..e3c23081 100644
--- a/instructor/aio.html
+++ b/instructor/aio.html
@@ -1583,7 +1583,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
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 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
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@@ -1703,7 +1703,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
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-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
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@@ -1890,7 +1890,7 @@ <h3 class="callout-title">Exercise (10 minutes)<a class="anchor" aria-label="anc
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
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 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
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 <div class="codewrapper sourceCode" id="cb29">
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@@ -2402,7 +2402,7 @@ <h3 class="callout-title">Starting from this episode<a class="anchor" aria-label
   <h3 class="accordion-header" id="headingSpoiler1">
 <div class="note-square"><i aria-hidden="true" class="callout-icon" data-feather="eye"></i></div>Read me</h3>
 </button>
-<div id="collapseSpoiler1" class="accordion-collapse collapse" aria-labelledby="headingSpoiler1" data-bs-parent="#accordionSpoiler1">
+<div id="collapseSpoiler1" class="accordion-collapse collapse" data-bs-parent="#accordionSpoiler1" aria-labelledby="headingSpoiler1">
 <div class="accordion-body">
 <p>In the previous episode, we ran a query on the Gaia server,
 downloaded data for roughly 140,000 stars, and saved the data in a FITS
@@ -2681,7 +2681,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
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 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb23">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -4668,7 +4668,7 @@ <h3 class="callout-title">Starting from this episode<a class="anchor" aria-label
   <h3 class="accordion-header" id="headingSpoiler1">
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 </button>
-<div id="collapseSpoiler1" class="accordion-collapse collapse" aria-labelledby="headingSpoiler1" data-bs-parent="#accordionSpoiler1">
+<div id="collapseSpoiler1" class="accordion-collapse collapse" data-bs-parent="#accordionSpoiler1" aria-labelledby="headingSpoiler1">
 <div class="accordion-body">
 <p>In the previous episode, we define a rectangle around stars in GD-1
 in spatial coordinates and in proper motion which we transformed into
@@ -5333,7 +5333,7 @@ <h3 class="callout-title">Exercise (15 minutes)<a class="anchor" aria-label="anc
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@@ -5501,7 +5501,7 @@ <h3 class="callout-title">Exercise (15 minutes)<a class="anchor" aria-label="anc
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
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 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb54">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -5981,11 +5981,12 @@ <h3 class="accordion-header" id="headingSpoiler2">
 headlights as they approach). Dust will remove light from the star’s
 path to our telescopes, which makes the star seem like it has less
 energy than it otherwise would have, which makes it do two things on
-this diagram: 1) look fainter (lower y-axis value) and 2) look cooler
-(higher x-axis value). The stars spread throughout the diagram are all
-stars bright enough to be detected in our Milky Way between GD-1 and us
-but made fainter and redder (spread to the lower-right) by their spread
-in distance from us and the amount dust in the line of sight.</p>
+this diagram: 1) look fainter (lower on the y-axis; larger magnitude
+value) and 2) look cooler (higher x-axis value). The stars spread
+throughout the diagram are all stars bright enough to be detected in our
+Milky Way between GD-1 and us but made fainter and redder (spread to the
+lower-right) by their spread in distance from us and the amount dust in
+the line of sight.</p>
 <p>GD-1: The pile up of stars in the lower-left quadrant of this diagram
 are interesting because it suggests something is at the same distance
 with the same amount of dust in the way. When we use our knowledge of
@@ -6702,7 +6703,7 @@ <h3 class="callout-title">Starting from this episode<a class="anchor" aria-label
   <h3 class="accordion-header" id="headingSpoiler1">
 <div class="note-square"><i aria-hidden="true" class="callout-icon" data-feather="eye"></i></div>Read me</h3>
 </button>
-<div id="collapseSpoiler1" class="accordion-collapse collapse" aria-labelledby="headingSpoiler1" data-bs-parent="#accordionSpoiler1">
+<div id="collapseSpoiler1" class="accordion-collapse collapse" data-bs-parent="#accordionSpoiler1" aria-labelledby="headingSpoiler1">
 <div class="accordion-body">
 <p>In the previous episode, we selected stars in GD-1 based on proper
 motion and downloaded the spatial, proper motion, and photometry
@@ -6801,7 +6802,7 @@ <h3 class="callout-title">Exercise (10 minutes)<a class="anchor" aria-label="anc
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution1" aria-expanded="false" aria-controls="collapseSolution1">
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 </button>
-<div id="collapseSolution1" class="accordion-collapse collapse" aria-labelledby="headingSolution1" data-bs-parent="#accordionSolution1">
+<div id="collapseSolution1" class="accordion-collapse collapse" data-bs-parent="#accordionSolution1" aria-labelledby="headingSolution1">
 <div class="accordion-body">
 <p>No figure is perfect, and everyone can be a critic. Here are some
 topics that could come up in this discussion:</p>
@@ -6883,7 +6884,7 @@ <h3 class="callout-title">Exercise (20 minutes)<a class="anchor" aria-label="anc
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution2" aria-expanded="false" aria-controls="collapseSolution2">
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 </button>
-<div id="collapseSolution2" class="accordion-collapse collapse" aria-labelledby="headingSolution2" data-bs-parent="#accordionSolution2">
+<div id="collapseSolution2" class="accordion-collapse collapse" data-bs-parent="#accordionSolution2" aria-labelledby="headingSolution2">
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@@ -7014,7 +7015,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution3" aria-expanded="false" aria-controls="collapseSolution3">
   <h4 class="accordion-header" id="headingSolution3">Show me the solution</h4>
 </button>
-<div id="collapseSolution3" class="accordion-collapse collapse" aria-labelledby="headingSolution3" data-bs-parent="#accordionSolution3">
+<div id="collapseSolution3" class="accordion-collapse collapse" data-bs-parent="#accordionSolution3" aria-labelledby="headingSolution3">
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 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -7072,7 +7073,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution4" aria-expanded="false" aria-controls="collapseSolution4">
   <h4 class="accordion-header" id="headingSolution4">Show me the solution</h4>
 </button>
-<div id="collapseSolution4" class="accordion-collapse collapse" aria-labelledby="headingSolution4" data-bs-parent="#accordionSolution4">
+<div id="collapseSolution4" class="accordion-collapse collapse" data-bs-parent="#accordionSolution4" aria-labelledby="headingSolution4">
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@@ -7195,7 +7196,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution5" aria-expanded="false" aria-controls="collapseSolution5">
   <h4 class="accordion-header" id="headingSolution5">Show me the solution</h4>
 </button>
-<div id="collapseSolution5" class="accordion-collapse collapse" aria-labelledby="headingSolution5" data-bs-parent="#accordionSolution5">
+<div id="collapseSolution5" class="accordion-collapse collapse" data-bs-parent="#accordionSolution5" aria-labelledby="headingSolution5">
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 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -7315,7 +7316,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution6" aria-expanded="false" aria-controls="collapseSolution6">
   <h4 class="accordion-header" id="headingSolution6">Show me the solution</h4>
 </button>
-<div id="collapseSolution6" class="accordion-collapse collapse" aria-labelledby="headingSolution6" data-bs-parent="#accordionSolution6">
+<div id="collapseSolution6" class="accordion-collapse collapse" data-bs-parent="#accordionSolution6" aria-labelledby="headingSolution6">
 <div class="accordion-body">
 <p>Without <code>tight_layout</code> the space between the panels is too
 small. In this situation, the titles from the lower plots overlap with
@@ -7383,7 +7384,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution7" aria-expanded="false" aria-controls="collapseSolution7">
   <h4 class="accordion-header" id="headingSolution7">Show me the solution</h4>
 </button>
-<div id="collapseSolution7" class="accordion-collapse collapse" aria-labelledby="headingSolution7" data-bs-parent="#accordionSolution7">
+<div id="collapseSolution7" class="accordion-collapse collapse" data-bs-parent="#accordionSolution7" aria-labelledby="headingSolution7">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb24">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -7512,7 +7513,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution8" aria-expanded="false" aria-controls="collapseSolution8">
   <h4 class="accordion-header" id="headingSolution8">Show me the solution</h4>
 </button>
-<div id="collapseSolution8" class="accordion-collapse collapse" aria-labelledby="headingSolution8" data-bs-parent="#accordionSolution8">
+<div id="collapseSolution8" class="accordion-collapse collapse" data-bs-parent="#accordionSolution8" aria-labelledby="headingSolution8">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb32">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
@@ -7545,7 +7546,7 @@ <h3 class="callout-title">Exercise (5 minutes)<a class="anchor" aria-label="anch
 <button class="accordion-button solution-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#collapseSolution9" aria-expanded="false" aria-controls="collapseSolution9">
   <h4 class="accordion-header" id="headingSolution9">Show me the solution</h4>
 </button>
-<div id="collapseSolution9" class="accordion-collapse collapse" aria-labelledby="headingSolution9" data-bs-parent="#accordionSolution9">
+<div id="collapseSolution9" class="accordion-collapse collapse" data-bs-parent="#accordionSolution9" aria-labelledby="headingSolution9">
 <div class="accordion-body">
 <div class="codewrapper sourceCode" id="cb33">
 <h3 class="code-label">PYTHON<i aria-hidden="true" data-feather="chevron-left"></i><i aria-hidden="true" data-feather="chevron-right"></i>
diff --git a/md5sum.txt b/md5sum.txt
index edae5c7e..1e2c9d25 100644
--- a/md5sum.txt
+++ b/md5sum.txt
@@ -9,7 +9,7 @@
 "episodes/04-motion.md" "c2642d107deb0093d78e111d359bd16f" "site/built/04-motion.md" "2024-03-08"
 "episodes/05-select.md" "600928a8a4997755e32c8755cfeb31fd" "site/built/05-select.md" "2024-03-08"
 "episodes/06-join.md" "6a80beb14e4d8a8daa5fbedd6685fe4e" "site/built/06-join.md" "2024-03-08"
-"episodes/07-photo.md" "010b8b3ce12417fc41e970627ddc3765" "site/built/07-photo.md" "2024-03-08"
+"episodes/07-photo.md" "1cc618a02e5cf609052e83abaebf0094" "site/built/07-photo.md" "2024-03-08"
 "episodes/08-plot.md" "abae0965c1415da07a22c13593bbfe4f" "site/built/08-plot.md" "2024-03-08"
 "instructors/calculating_MIST_isochrone.md" "3201f3ca13dc11bbef74a7d24a433362" "site/built/calculating_MIST_isochrone.md" "2023-05-15"
 "instructors/instructor-notes.md" "89d23bec26e7345459eb2621bd2c73d5" "site/built/instructor-notes.md" "2023-05-15"
diff --git a/pkgdown.yml b/pkgdown.yml
index 6195dcfd..6ba38d16 100644
--- a/pkgdown.yml
+++ b/pkgdown.yml
@@ -2,5 +2,5 @@ pandoc: 3.1.11
 pkgdown: 2.0.7
 pkgdown_sha: ~
 articles: {}
-last_built: 2024-03-08T23:43Z
+last_built: 2024-03-08T23:44Z