diff --git a/src/Identify.tex b/src/Identify.tex
index 0a77e30..fd3e63d 100644
--- a/src/Identify.tex
+++ b/src/Identify.tex
@@ -49,7 +49,6 @@ My fork is here:
 
 * \url{https://spacecruft.org/spacecruft/sattools}
 
-% https://spacecruft.org/spacecruft/sattools/media/branch/spacecruft/img/satid-giza-3.png
 \begin{figure}[h!]
 	\begin{center}
 		\includegraphics[keepaspectratio=true,height=0.40\textheight,width=1.00\textwidth,angle=0]{satid-giza-3.png}
diff --git a/src/Software.tex b/src/Software.tex
index 97d2f27..acb6b5c 100644
--- a/src/Software.tex
+++ b/src/Software.tex
@@ -182,5 +182,95 @@ inparallel
 
 
 \section{skymap}
-Use \gls{skymap} for viewing \gls{satellite} \gls{orbit} predictions.
+Use \gls{skymap} for viewing \gls{satellite} \glspl{orbit} tracks
+projected on a map of of the sky. Skymap is part of \gls{sattools}.
 
+Source:
+
+* \url{https://github.com/cbassa/sattools}
+
+My fork:
+
+* \url{https://spacecruft.org/spacecruft/sattools}
+
+\begin{figure}[h!]
+        \begin{center}
+                \includegraphics[keepaspectratio=true,height=0.40\textheight,width=1.00\textwidth,angle=0]{skymap-giza-21.png}
+                \caption{\texttt{skymap} example screenshot.}
+                \index{skymap}\index{sattools}
+                \label{fig:skymap-giza-21}
+        \end{center}
+\end{figure}
+
+\fbox{
+        \parbox{\linewidth}{
+                \textcolor{red}{NOTICE:} \\
+                The main upstream sattools package requires non-\gls{libre} pgplot on host computer.
+                \index{proprietary}
+        }
+}
+
+Described below is how to build and install my fork of \gls{sattools} to use
+\gls{skymap} instead of upstream. Upstream requires non-libre software which
+also happens to be very difficult for most users to compile.
+
+\begin{minted}{sh}
+sudo apt install giza-dev git make dos2unix source-extractor wcslib-dev \
+     libgsl-dev gfortran libpng-dev libx11-dev libjpeg-dev libexif-dev
+
+git clone https://spacecruft.org/spacecruft/sattools
+
+cd sattools/
+
+make
+
+sudo make install
+
+# To clean
+make clean
+
+# To rebuild
+make clean
+make
+
+# To uninstall
+sudo make uninstall
+\end{minted}
+
+See below for \gls{skymap} usage:
+
+\begin{minted}{sh}
+cd bin/
+./tleupdate
+
+# set config in ~/.bashrc XXX
+
+./skymap --help
+Usage: skymap [OPTION]
+Visualize satellites on a map of the sky.
+
+-t, --time    Date/time (yyyy-mm-ddThh:mm:ss.sss) [default: now]
+-c, --catalog    TLE catalog file [default: satnogs.tle]
+-i, --id    Satellite ID (NORAD) [default: all]
+-R, --ra    R.A. [hh:mm:ss.sss]
+-D, --decl    Decl. [+dd:mm:ss.ss]
+-A, --azimuth    Azimuth (deg)
+-E, --elevation    Elevation (deg)
+-w, --width    Screen width (default: 1024). Set height too.
+-g, --height    Screen height (default: 768). Set width too.
+-n, --nmax    nmax line resolution/speed (default 128)
+-S, --all-night    All night
+-Q, --no-stars    No stars
+-a, --all-objects    Show all objects from catalog (default: LEO)
+-h, --help    This help
+-s, --site    Site (COSPAR)
+-d, --iod    IOD observations
+-l, --length    Trail length [default: 60s]
+-P, --planar-id    planar search satellite ID
+-r, --planar-alt    planar search altitude
+-V, --visibility-alt    altitude for visibility contours
+-p, --positions-file    File with xyz positions
+-L, --longitude    manual site longitude (deg)
+-B, --latitude    manual site latitude (deg)
+-H, --elevation    manual site elevation (m)
+\end{minted}
diff --git a/src/figures/skymap-giza-21.png b/src/figures/skymap-giza-21.png
new file mode 100644
index 0000000..e202678
Binary files /dev/null and b/src/figures/skymap-giza-21.png differ