[custom] fix lesson contents

episodes/04-motion.md

@@ -150,7 +150,7 @@ Price-Whelan and Bonaca paper, the one that shows components of proper
 motion as a scatter plot:
 
 <img width="300"
-src="../fig/gd1-1.png" alt="Scatter of proper motion phi1 versus phi2 showing overdensity in negative proper motions of GD-1 stars.">
+src="fig/gd1-1.png" alt="Scatter of proper motion phi1 versus phi2 showing overdensity in negative proper motions of GD-1 stars.">
 
 In this figure, the shaded area identifies stars that are likely to be
 in GD-1 because:
@@ -396,7 +396,7 @@ In the original paper, Price-Whelan and Bonaca used a polygon to cover
 this region, as shown in this figure.
 
 <img width="300"
-src="../fig/gd1-1.png" alt="Scatter plot of proper motion with overlaid polygon showing overdense region selected for analysis in Price-Whelan and Bonaca paper.">
+src="fig/gd1-1.png" alt="Scatter plot of proper motion with overlaid polygon showing overdense region selected for analysis in Price-Whelan and Bonaca paper.">
 
 We will use a simple rectangle for now, but in a later lesson we will see
 how to select a polygonal region as well.

episodes/05-select.md

@@ -546,7 +546,7 @@ We can compare this figure with this panel from Figure 1 from the
 original paper:
 
 <img height="150"
-src="../fig/gd1-2.png" alt="Figure from Price-Whelan and Bonaca paper showing phi1 vs phi2 in GD-1 after selecting on proper motion.">
+src="fig/gd1-2.png" alt="Figure from Price-Whelan and Bonaca paper showing phi1 vs phi2 in GD-1 after selecting on proper motion.">
 
 This panel shows stars selected based on proper motion only, so it is
 comparable to our figure (although notice that the original figure covers a wider
@@ -556,7 +556,7 @@ In the next episode, we will use photometry data from Pan-STARRS to do
 a second round of filtering, and see if we can replicate this panel.
 
 <img height="150"
-src="../fig/gd1-4.png" alt="Figure from Price-Whelan and Bonaca paper showing phi1 vs phi2 in GD-1 after selecting on proper motion and photometry.">
+src="fig/gd1-4.png" alt="Figure from Price-Whelan and Bonaca paper showing phi1 vs phi2 in GD-1 after selecting on proper motion and photometry.">
 
 Later we will learn how to add annotations like the ones in the figure and
 customize the style of the figure to present the results clearly and

episodes/06-join.md

@@ -27,7 +27,7 @@ The following figure from the Price-Whelan and Bonaca paper is a color-magnitude
 the stars selected based on proper motion:
 
 <img width="300"
-src="../fig/gd1-3.png" alt="Color-magnitude diagram for the stars selected based on proper motion, from Price-Whelan and Bonaca paper.">
+src="fig/gd1-3.png" alt="Color-magnitude diagram for the stars selected based on proper motion, from Price-Whelan and Bonaca paper.">
 
 In red is a [stellar
 isochrone](https://en.wikipedia.org/wiki/Stellar_isochrone), showing
@@ -411,7 +411,7 @@ If you are curious, you can [read more about
 it](https://chartio.com/learn/databases/how-does-indexing-work/).
 
 <img
-src="../fig/join.png" alt="Diagram showing relationship between the gaia_source, panstarrs1_best_neighbour, and panstarrs1_original_valid tables and result table.">
+src="fig/join.png" alt="Diagram showing relationship between the gaia_source, panstarrs1_best_neighbour, and panstarrs1_original_valid tables and result table.">
 
 Now we will get to the details of performing a `JOIN` operation.
 

episodes/07-photo.md

@@ -29,7 +29,7 @@ The following figure from the paper is a color-magnitude diagram
 showing the stars we previously selected based on proper motion:
 
 <img width="300"
-src="../fig/gd1-3.png" alt="Color-magnitude diagram for the stars selected based on proper motion, from Price-Whelan and Bonaca paper.">
+src="fig/gd1-3.png" alt="Color-magnitude diagram for the stars selected based on proper motion, from Price-Whelan and Bonaca paper.">
 
 In red is a [theoretical isochrone](https://en.wikipedia.org/wiki/Stellar_isochrone), showing where we expect the stars
 in GD-1 to fall based on the metallicity and age of their original
@@ -105,7 +105,7 @@ diagram](https://coolwiki.ipac.caltech.edu/index.php/Color-Magnitude_and_Color-C
 to replicate the diagram from the original paper:
 
 <img width="300"
-src="../fig/gd1-3.png" alt="Color-magnitude diagram for the stars selected based on proper motion, from Price-Whelan and Bonaca paper.">
+src="fig/gd1-3.png" alt="Color-magnitude diagram for the stars selected based on proper motion, from Price-Whelan and Bonaca paper.">
 
 The y-axis shows the apparent magnitude of each source with the [g
 filter](https://en.wikipedia.org/wiki/Photometric_system).

episodes/08-plot.md

@@ -122,7 +122,7 @@ the individual panels, but now we will look at the whole figure, along
 with the caption:
 
 <img style="max-width: 100%;"
-src="../fig/gd1-5.png" alt="Figure 1 from Price-Whelan and Bonaca paper with four panels and caption. Caption reads: On-sky positions of likely GD-1 members in the GD-1 coordinate system. GD-1 is apparent as an overdensity in negative proper motions (top-right panel, orange box), so selecting on proper motion already reveals the stream in positions of individual stars (top-left panel). The stream also stands out in the color–magnitude diagram (bottom-right panel) as older and more metal-poor than the background. Selecting the main sequence of GD-1 (orange, shaded region in the bottom-right panel) along with proper motion cuts unveils the stream in unprecedented detail (bottom-left panel).">
+src="fig/gd1-5.png" alt="Figure 1 from Price-Whelan and Bonaca paper with four panels and caption. Caption reads: On-sky positions of likely GD-1 members in the GD-1 coordinate system. GD-1 is apparent as an overdensity in negative proper motions (top-right panel, orange box), so selecting on proper motion already reveals the stream in positions of individual stars (top-left panel). The stream also stands out in the color–magnitude diagram (bottom-right panel) as older and more metal-poor than the background. Selecting the main sequence of GD-1 (orange, shaded region in the bottom-right panel) along with proper motion cuts unveils the stream in unprecedented detail (bottom-left panel).">
 
 :::::::::::::::::::::::::::::::::::::::  challenge
 

instructors/instructor-notes.md

@@ -216,7 +216,7 @@ objects we are saving are small.
 
 - The key take away from the CMD presentation is that GD-1 is a globular cluster which means all of the stars formed at the same time. Therefore we expect the stars in GD-1 to follow a single, tight isochrone, the main sequence of which we can easily identify.
 
-- We did have to manipulate the MIST isochrone to get it from what is available for download to what we read in. This is too much detail for the curriculum, but the process is detailed in [Making the Isochrone Dataframe](/astronomy-python/calculating_MIST_isochrone) if you or a learner is interested.
+- We did have to manipulate the MIST isochrone to get it from what is available for download to what we read in. This is too much detail for the curriculum, but the process is detailed in [Making the Isochrone Dataframe](calculating_MIST_isochrone.md) if you or a learner is interested.
 
 - In the original paper, they use an idiosyncratic function to define the boundaries of the isochrone filter. The intention is to define a polygon that gets wider as g increases, to reflect increasing uncertainty. For this exercise we will be using a simplified version which is a constant offset from the isochrone.