Lab_3/Lab_3.ipynb

@@ -4,14 +4,14 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "# <p style=\"text-align: center;\">PHYS 134L Spring 2024 Lab 3</p>"
+    "# <p style=\"text-align: center;\">PHYS 134L Spring 2022 Lab 3</p>"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "<div class=\"alert alert-block alert-danger\"><b>Due date:</b> Sunday, April 28th, 2024 by 11:59pm, submitted through Gradescope.</div>"
+    "<div class=\"alert alert-block alert-danger\"><b>Due date:</b> Sunday, April 24th, 2022 by 11:59pm, submitted through Gradescope.</div>"
    ]
   },
   {
@@ -32,7 +32,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "Read through this entire lab before you start. In this lab, we will look at the brightness of stars as measured in astronomical units called ''magnitudes.'' To complete this lab you should have already read textbook Chapter 3 and Sections 2.3 and 2.4. In this lab, you will be asked to type out some equations. In a jupyter notebook you can do this using standard LaTeX math notation. If you're new to LaTeX you can use [this online equation editor](https://latex.codecogs.com/) to help you along to start. Later in this course you'll be using LaTeX for your final report. "
+    "Read through this entire lab before you start. In this lab, we will look at the brightness of stars as measured in astronomical units called ''magnitudes.'' To complete this lab you should have already read textbook Chapter 3 and Sections 2.3 and 2.4. In this lab, you will be asked to type out some equations. In a jupyter notebook you can do this using standard LATEX math notation. If you're new to LATEX you can use [this online equation editor](https://latex.codecogs.com/) to help you along to start. Later in this course you'll be using La"
    ]
   },
   {
@@ -304,7 +304,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "Last lab, you estimated the angular sizes of a few stars; the largest size you should have computed was around 2~mas.  You also computed the pixel scale in these images; you should have gotten a scale of around $0.^{\\prime \\prime}58$ arcsec/pixel. **Use these two numbers to estimate the angular size of a star in units of pixels.  Please show your work for the unit conversion.**"
+    "Last lab, you estimated the angular sizes of a few stars; the largest size you should have computed was around 2~mas.  You also computed the pixel scale in these images; you should have gotten a scale of around $0.\\!\\!^{\\prime \\prime}58$ arcsec/pixel. **Use these two numbers to estimate the angular size of a star in units of pixels.  Please show your work for the unit conversion.**"
    ]
   },
   {
@@ -355,14 +355,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "For telescopes on the ground, the FWHM in an image is set either  by:  a) the atmospheric turbulence, where the atmosphere blurs out light passing through it, or b) the telescope primary mirror diameter, which introduces diffraction and limits the FWHM of the point spread function to be ~$\\lambda/D$ (in radians). When limited by the atmosphere, a better site gives a shaper image; the size of the atmospheric FWHM we call the ''seeing'' (typically expressed in arcseconds). Try to find on the internet the typical seeing for a few different astronomical telescope sites: Mauna Kea, Paranal and one site of your choice. Compare this to the diffraction limit of a couple telescopes at each those sites, when observing at 600nm. \n"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "metadata": {},
-   "source": [
-    "*Your answer here*"
+    "For telescopes on the ground, the FWHM is usually set by atmospheric turbulence and is called ''seeing.''  A better site gives a shaper image. \n"
    ]
   },
   {
@@ -491,7 +484,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "**Now use the flux-vs-magnitude expression from Part 1 to write an expression for $N_{\\rm phot}$ as a function of ```MAG_ISOCOR```.**"
+    "**Now use the flux-vs-magnitude expression from page 2 to write an expression for $N_{\\rm phot}$ as a function of ```MAG_ISOCOR```.**"
    ]
   },
   {
@@ -506,7 +499,7 @@
    "metadata": {},
    "source": [
     "The expected counting error (measured in photo-electrons) is the square root of $N_{\\rm phot}$. To get the noise in units of counts, we must\n",
-    "divide by the ```GAIN```. **Write an expression for this counting error as a function of MAG_ISOCOR.**\n"
+    "divide by the ```GAIN```. **Write an expression for this counting error as a function of MAG_ISOCOR}.**\n"
    ]
   },
   {
@@ -561,23 +554,7 @@
     "\n",
     "```x = np.arange(int(np.amin(mags)), int(np.amax(mags)) + 1)```\n",
     "\n",
-    "**and evaluate your expression for magnitude uncertainties at these integer ```x``` values.  Overplot this on your plot of ```MAGERR_ISOCOR``` vs.~```MAG_ISOCOR``` using a thick, red line. Comment on whether they match or not**"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "#Your Code here"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "metadata": {},
-   "source": [
-    "*Your answer here*"
+    "**and evaluate your expression for magnitude uncertainties at these integer ```x``` values.  Overplot this on your plot of ```MAGERR_ISOCOR``` vs.~```MAG_ISOCOR``` using a thick, red line.**"
    ]
   },
   {
@@ -592,7 +569,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "Now we know how to use the data from Source Extractor to estimate the fluxes and magnitudes of stars, and also the precision that simple physics says we should be achieving. But how well do we know our errors, really? Might effects other than photon counting statistics be dominant? And what about systematic errors, which give us consistent and repeatable wrong answers? How can we test for these?\n",
+    "Now we know how to use Source Extractor output to estimate the fluxes and magnitudes of stars, and also the precision that simple physics says we should be achieving. But how well do we know our errors, really? Might effects other than photon counting statistics be dominant? And what about systematic errors, which give us consistent and repeatable wrong answers? How can we test for these?\n",
     "\n",
     "\n",
     "Source Extractor can estimate source fluxes in several ways – two of these are isophotal photometry (which deals well with objects having funny shapes) and aperture photometry (which works well for perfectly round objects, as star images are supposed to be). Check section 7.4 of *Source Extractor for Dummies* for an explanation of what these things mean. The picture on p.~41 is particularly helpful.\n",