forked from spacecruft/SNOUG
455 lines
17 KiB
TeX
455 lines
17 KiB
TeX
%
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% Hardware.tex
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%
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% SatNOGS Optical Unofficial Guide
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%
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% Copyright (C) 2022, Jeff Moe
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%
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% This document is licensed under the Creative Commons Attribution 4.0
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% International Public License (CC BY-SA 4.0) by Jeff Moe.
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%
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\section{Overview of Hardware}
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\label{sec:hardware-overview}
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\index{hardware}
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Hardware considerations for a \gls{SatNOGS-Optical} \gls{ground-station}.
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Main hardware components in an optical \gls{ground-station}:
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\begin{mdframed}[backgroundcolor=blue!10,linecolor=blue!30]
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\begin{itemize}
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\item Lens. \index{lens}
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\item Camera. \index{camera}
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\item Computer. \index{computer}
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\end{itemize}
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\end{mdframed}
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\index{lens}\index{camera}\index{embedded computer}
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Other components:
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\begin{mdframed}[backgroundcolor=blue!10,linecolor=blue!30]
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\begin{itemize}
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\item Ethernet cable. \index{ethernet}
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\item \gls{USB} cable. \index{USB}
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\item Enclosure. \index{enclosure}
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\item Power supply. \index{power supply}
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\item Tripod. \index{tripod}
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\item Manual or tracking mount. \index{mount}
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\item Power source, grid or alternative.
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\item Internet, wifi or ethernet.
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\end{itemize}
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\end{mdframed}
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\index{ethernet}\index{USB}\index{enclosure}\index{power supply}
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\index{tripod}\index{mount}\index{wifi}
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\section{Camera}
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\label{sec:hardware-camera}
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Cameras being evaluated:
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\begin{mdframed}[backgroundcolor=blue!10,linecolor=blue!30]
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\begin{itemize}
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\item The Imaging Source IMX174 based, monochrome. \index{The Imaging Source}\index{IMX174}
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\item ZWO ASI174MM, monochrome. \index{ZWO ASI}
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\item ZWO ASI1600MM Pro, monochrome. \index{ZWO ASI}
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\item \gls{DSLR} camera. \index{DSLR}
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\item PiCamera. \index{PiCamera}
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\end{itemize}
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\end{mdframed}
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\fbox{
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\parbox{\linewidth}{
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\textcolor{red}{NOTICE:} \\
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ZWO/ASI cameras require proprietary non-libre software on host computer and is not \gls{DFSG} compatible.
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\index{proprietary}\index{DFSG}
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}
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}
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\section{Lenses}
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\label{sec:hardware-lenses}
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\index{lens}
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For lenses, the faster the better.
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F1.2 works well.
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F1.8 is the maxmimum recommended.
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Lenses being tested:
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\begin{mdframed}[backgroundcolor=blue!10,linecolor=blue!30]
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\begin{itemize}
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\item Kowa 50mm f1.4 C-mount. \index{Kowa}
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\item Canon EF 50mm f1.2 USM. \index{Canon}
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\end{itemize}
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\end{mdframed}
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\section{Embedded Computer}
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\label{sec:hardware-computer}
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\index{hardware}\index{embedded computer}
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Embedded computers, such as Raspberry Pi, that can be used.
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\index{Raspberry Pi}
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\begin{mdframed}[backgroundcolor=blue!10,linecolor=blue!30]
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\begin{description}
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\item [Odroid N2] --- Confirmed working. \index{Odroid}
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\item [Odroid M1] --- Testing.
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\item [Raspberry Pi 3] --- ? \index{Raspberry Pi}
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\item [Raspberry Pi 4] --- ? \index{Raspberry Pi}
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\item [Intel \gls{NUC}] --- ? \index{Intel}
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\end{description}
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\end{mdframed}
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\subsection{Comparison}
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Comparing embedded computers for \gls{SatNOGS-Optical}.
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\index{embedded computer}
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\begin{center}
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\begin{table}[ht]
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\begin{mdframed}[backgroundcolor=blue!10,linecolor=blue!30]
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\begin{center}
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\hspace*{-1.5cm}
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\begin{tabularx}{250pt}{|c|c|c|c|c|}
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\hline
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Make & Model & Architecture & Max RAM & eMMC\\
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\hline
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Odroid & N2 & ARM64 & 4 GB & Yes\\
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\hline
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Odroid & M1 & ARM64 & 8 GB & Yes\\
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\hline
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\end{tabularx}
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\caption{Comparison of embedded computers}
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\label{compare-embed}
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\end{center}
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\end{mdframed}
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\end{table}
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\end{center}
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\index{Odroid}\index{ARM64}\index{eMMC}
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\section{Example Optical Ground Station with Tracking}
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\label{sec:hardware-tracking-ground-station}
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\index{ground station}\index{mount}\index{tracking}
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\index{tripod}
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This is an example of a tracking \gls{ground-station}.
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It is a prototype, so there are lots of mis-matched,
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overbuilt/underbuilt parts.
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The full setup on tripod, can be seen in
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\ref{fig:video-enclosure-mount-tripod}, page \pageref{fig:video-enclosure-mount-tripod}.
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A close up of the setup can be seen at
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\ref{fig:video-enclosure-mount}, page \pageref{fig:video-enclosure-mount},
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showing the Sky-Watcher telescope tracking mount,
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a Bosch \gls{PoE} camera enclosure,
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and through the glass the camera lens.
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\index{Sky-Watcher}\index{telescope}\index{mount}\index{Bosch}\index{PoE}\index{camera}
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\index{lens}
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In the background is a white \gls{antenna} for \gls{GNSS} (\gls{GPS}) and a solar power setup.
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\index{GNSS}\index{GPS}\index{solar power}
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\begin{figure}[p!]
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\begin{center}
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\includegraphics[keepaspectratio=true,height=1.00\textheight,width=1.00\textwidth,angle=0]{video-enclosure-mount.png}
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\caption{SatNOGS-Optical ground station prototype.}
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\label{fig:video-enclosure-mount}
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\index{telescope}\index{mount}\index{camera}
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\end{center}
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\end{figure}
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The camera lens is protected by the enclosure glass, which is \gls{IP67} (XXX) rated.
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See a close up of the front of the enclosure and camera lens in figure
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\ref{fig:video-enclosure-front}, page \pageref{fig:video-enclosure-front}.
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\begin{figure}[h!]
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\begin{framed}
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\begin{center}
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\includegraphics[keepaspectratio=true,height=0.40\textheight,width=1.00\textwidth,angle=0]{video-enclosure-front.png}
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\caption{Camera enclosure, front side, showing glass and lens.}
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\label{fig:video-enclosure-front}
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\index{enclosure}\index{camera}
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\end{center}
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\end{framed}
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\end{figure}
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As seen in figure
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\ref{fig:video-enclosure-left}, page \pageref{fig:video-enclosure-left},
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the left side of the enclosure has a hinge for opening.
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The bottom white component is part of the telescope mount.
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\begin{figure}[h!]
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\begin{framed}
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\begin{center}
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\includegraphics[keepaspectratio=true,height=0.40\textheight,width=1.00\textwidth,angle=0]{video-enclosure-left.png}
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\caption{Camera enclosure, left side, showing hinge.}
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\label{fig:video-enclosure-left}
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\index{enclosure}\index{camera}
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\end{center}
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\end{framed}
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\end{figure}
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Figure
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\ref{fig:video-enclosure-right}, page \pageref{fig:video-enclosure-right},
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shows the right side of the enclosure.
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Two mounting bolt access points can be seen on each end.
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These are unscrewed with a hex head tool (supplied) to open the enclosure.
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\index{enclosure}
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\begin{figure}[h!]
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\begin{framed}
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\begin{center}
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\includegraphics[keepaspectratio=true,height=0.40\textheight,width=1.00\textwidth,angle=0]{video-enclosure-right.png}
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\caption{Camera enclosure, right side.}
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\label{fig:video-enclosure-right}
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\index{enclosure}\index{camera}
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\end{center}
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\end{framed}
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\end{figure}
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The enclosure is opened from the right side, as shown in figure
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\ref{fig:video-enclosure-right}, page \pageref{fig:video-enclosure-right}.
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\begin{sidewaysfigure}[p!]
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\begin{center}
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\includegraphics[keepaspectratio=true,height=1.00\textheight,width=1.00\textwidth,angle=0]{video-enclosure-right-open.png}
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\caption{Camera enclosure, right side, opened.}
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\label{fig:video-enclosure-right-open}
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\index{enclosure}\index{camera}
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\end{center}
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\end{sidewaysfigure}
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Inside the camera enclosure, as shown in Figure
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\ref{fig:video-enclosure-top-open}, page \pageref{fig:video-enclosure-top-open},
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is:
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\begin{mdframed}[backgroundcolor=blue!10,linecolor=blue!30]
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\begin{itemize}
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\item The Imaging Source DMX camera with Sony IMX174 \gls{CMOS}. \index{The Imaging Source}\index{IMX174}
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\item Kowa 50mm f1.4 C-mount lens.\index{Kowa}
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\item Odroid N2 running \gls{Debian} \gls{GNU} \gls{Linux} system. \index{Odroid}\index{Debian}\index{GNU}\index{Linux}
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\item Odroid N2 plastic enclosure, large half, hole drilled for ad-hoc mounting.
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\item Blower fan on top, with power cable (came with Bosch enclosure). \index{fan}
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\item Fan, maybe not so useful, with power cable (came with Bosch enclosure).
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\item Camera mounting plate (came with Bosch enclosure). \index{camera}
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\item Camera mounting screws, M6x25 (?).
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\item Ethernet cable, internal, short white (came with Bosch enclosure). \index{ethernet}
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\item \gls{PoE} ethernet cable, external, plugged into \gls{PoE} switch for data and power. \index{PoE}
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\item \gls{USB} 3 cable, internal, way too long, needs replacing, from Odroid to camera. XXX flat connector
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\item \gls{USB} 3 cable, external, from Odroid to telescope mount. XXX large rectangle connector \index{USB}
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\item ``Custom'' 12\gls{V} \gls{DC} power cable from Bosch \gls{PoE} to Odroid.
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\item Assorted nuts, bolts, and washers for an ad-hoc standoff height.
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\end{itemize}
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\end{mdframed}
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\index{camera}\index{Kowa}\index{The Imaging Source}\index{Odroid}\index{Debian}
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\index{fan}\index{power cable}\index{mount plate}\index{Bosch}
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\index{ethernet cable}\index{PoE}\index{USB}\index{power cable}
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\begin{sidewaysfigure}[p!]
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\begin{center}
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\includegraphics[keepaspectratio=true,height=1.00\textheight,width=1.00\textwidth,angle=0]{video-enclosure-top-open.png}
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\caption{Camera enclosure, opened.}
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\label{fig:video-enclosure-top-open}
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\index{enclosure}\index{camera}
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\end{center}
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\end{sidewaysfigure}
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The top of the enclosure shows weather protection and a sun visor.
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See figure \ref{fig:video-enclosure-top}, page \pageref{fig:video-enclosure-top}.
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\begin{figure}[h!]
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\begin{framed}
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\begin{center}
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\includegraphics[keepaspectratio=true,height=0.40\textheight,width=1.00\textwidth,angle=0]{video-enclosure-top.png}
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\caption{Camera enclosure, top.}
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\label{fig:video-enclosure-top}
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\index{enclosure}\index{camera}
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\end{center}
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\end{framed}
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\end{figure}
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\section{Tripods}
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\label{sec:hardware-tripod}
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\index{hardware}\index{tripod}\index{camera}
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The camera setup can be mounted a wide variety of ways,
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from just setting the camera somewhere (worst option), to a heavy duty
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pier with tracking mount (best option).
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At present, most prototype optical ground stations are using static mounts
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on tripods.
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Tripod and similar options include:
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\begin{mdframed}[backgroundcolor=blue!10,linecolor=blue!30]
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\begin{description}
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\item [No mount] --- Quick and dirty, just hang the camera out somewhere sitting on something.
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\item [Small tripod] --- There are small desk tripods than can be used with lighter
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setups, such as used with a Raspberry Pi PiCamera.
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\item [Photography Tripod] --- Using a common camera tripod, of which there is a wide
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variety, from light to heavy.
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\item [Telescope Tripod] --- Similar to photography tripods, but typically heavier weight.
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\item [Telescope Portable Pier] --- Similar to a telescope tripod, but much heavier, typically
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with a larger center pier post. Still movable, and folds up similar to a photography tripod.
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\item [Telescope Pier] --- A wide variety, such as making a roughly 1.5 meter permanent cement post.
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\end{description}
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\end{mdframed}
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\index{pier}
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\section{Mounts}
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\label{sec:hardware-mounts}
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\index{mount}\index{track}
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For mounts, there are two main types: tracking or static.
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By the latter ``static'' mounts, it is meant that the
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camera, the tripod, and the mount all stay motionless.
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This is what you would get using a camera with a common photography
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tripod and a simple mounting plate.
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Static mounting options include:
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\begin{mdframed}[backgroundcolor=blue!10,linecolor=blue!30]
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\begin{description}
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\item [Camera plate] --- Commonly used on cameras and readily available for mounting
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cameras to tripods.
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\item [Enclosure plate] --- A flat plate with holes drilled in it to mount the camera
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inside an enclosure.
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\item [``Security'' camera enclosure mount] --- Various mounts exist to mount
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security cameras to posts, walls, etc.
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\end{description}
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\end{mdframed}
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\index{camera}\index{mount}
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Tracking mount options to consider include:
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\begin{mdframed}[backgroundcolor=blue!10,linecolor=blue!30]
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\begin{description}
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\item [Sky-Watcher EQ6-R Pro] --- Telescope mount using \gls{INDI}.
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\item [Celestron] --- Wide variety of telescope mounts using \gls{INDI}.
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\item [iOptron] --- Telescope mount with (untested) satellite tracking.
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\item [INDI Telescope Mounts] --- A wide variety of other \gls{INDI} compatible telescope mounts.
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\item [Yaesu G-5500] --- Antenna \gls{rotator}.
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\item [hamlib] --- Other hamlib compatible \glspl{rotator}.
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\item [FLIR PTU-5] --- High Performance Pan-Tilt Unit designed for security cameras (untested, no drivers?).
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\item [Misc PTZ] --- Other security camera pan/tilt mounts.
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\end{description}
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\end{mdframed}
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\index{track}\index{mount}\index{Sky-Watcher}\index{INDI}\index{Celestron}
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\index{Yaesu}\index{rotator}\index{hamlib}\index{FLIR}\index{pan/tilt}
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\index{iOptron}
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Tracking mounts aren't widely used, but there is support for them in
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\texttt{stvid} when acquiring data.
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The tracking needs to be set up independently of \texttt{stvid}.
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At present, I use KStars with Ekos to control a Sky-Watcher tracking
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mount.
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\index{KStars}\index{Ekos}\index{Sky-Watcher}\index{stvid}\index{track}
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For tracking, there a few different ways to track:
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\begin{mdframed}[backgroundcolor=blue!10,linecolor=blue!30]
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\begin{description}
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\item [Static] --- No tracking, just point at one place in the sky.
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Generates star trails.
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Generates satellite trails.
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\item [Sidereal tracking] --- Tracks stars.
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Generates stars as points.
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Generates satellite trails.
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\item [Satellite tracking] --- Tracks satellites.
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Generates stars as tracks.
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Generates satellites as points or potentially larger images
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of the satellite structure.
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\end{description}
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\end{mdframed}
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\subsection{Sidereal Tracking Mounts}
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Sidereal tracking (``telescope tracking'') is what \gls{COTS} tracking ``GOTO''
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\glspl{telescope} from Celestron or Sky-Watcher do, for example. They track
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the stars, countering the rotation of the Earth to keep the same view
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of the sky in the camera's \gls{FOV}. Stars remain as points, even after multi-minute
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or multi-hour imaging. This is what is used for ``pretty'' pictures
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of stars, nebula, galaxies, etc.
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This is the most common tracking set up, as it has been widely used in
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astronomy communities for decades.
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Within sidereal tracking mounts, there are yet more options:
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\begin{mdframed}[backgroundcolor=blue!10,linecolor=blue!30]
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\begin{description}
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\item [Fork] --- Fork mount.
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\item [\gls{EQ} fork] --- Fork on \gls{EQ} mount.
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\item [German \gls{EQ}] --- Most common \gls{EQ} mount.
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\item [More] --- Endless variety of available telescope mounts.
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\end{description}
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\end{mdframed}
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\index{German \gls{EQ}}\index{fork} %XXX
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\index{mount}\index{track}
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Also related to sidereal tracking is lunar and planetary
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tracking, but for our uses all three will be included under sidereal tracking.
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To use a sidereal tracking mount for imaging satellites, the camera
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must ``leap frog'' the satellite.
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At present, my practice is to use a sidereal mount, point at a location with KStars,
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start stvid. Then stop stvid, move to new location using KStars,
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start stvid.
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\index{track}\index{KStars}\index{stvid}
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See Software section XXX for information on using tracking mounts.
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\subsection{Satellite Tracking Mounts}
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\index{track}\index{mount}
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Of the options between a static mount (no tracking), sidereal tracking,
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and satellite tracking, the latter is by far the least common.
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In this case, the tracking mount is tracking the satellite itself.
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This is much more complex than tracking stars, which it builds upon.
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It requires, such as:
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\begin{mdframed}[backgroundcolor=blue!10,linecolor=blue!30]
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\begin{description}
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\item [Time] --- Accurate time, such as from \gls{GNSS}.
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\item [Location] --- Accurate location, also available from \gls{GNSS}.
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\item [\gls{TLE}] --- Need to know the \glspl{satellite}' orbit (accurately!).
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\item [Variable speed tracking] --- \Glspl{satellite} are moving at different
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speeds above, the mount needs to be capable of that.
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\item [Human guided] --- Some skilled amateurs track by hand.
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\item [Alignment] --- On top of all the gear and software needed,
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the equipment needs to be accurately aligned.
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\end{description}
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\end{mdframed}
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\index{GNSS}\index{TLE}
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Most tracking equipment for \glspl{telescope},
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cameras, and antennas usually has just a few speeds, such as a slewing speed
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and a sidereal star tracking speed. Sometimes there will be a few steps
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of these speeds (e.g. slew speeds from 1-9), but not the finely tuned tracking
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speeds needed to track a satellite. Oftentimes the telescope tracking maximum
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speed will be too slow for satellite tracks.
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Variable speed tracking (XXX phrase?) is needed for tracking satellites if
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the goal is to keep the satellite in the (near) center of the image frame
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and leave star trails. The speed the mount moves needs to be calculated
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based upon a recent orbit calcuation, such as from a \gls{TLE}.
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There are highly skilled amateur astronomers that have captured detailed
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pictures of artificial satellites, such as the \gls{ISS} and astronauts doing
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space walks, using hand guided telescopes with low cost \gls{CCD} imagers.
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\index{CCD}\index{ISS}
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% XXX ref
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There are few options for satellite tracking mounts.
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Some new iOptron telescope mount firmware supports tracking
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satellites. This has been largely untested so far, but at present
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is likely the best option, if a satellite tracking mount is wanted.
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\index{iOptron}\index{track}\index{mount}
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\section{Future Designs}
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\label{sec:hardware-future}
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\index{RASA}\index{telescope}\index{astrograph}
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\index{rotator}\index{antenna}
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There is some discussion of using much larger ``lenses'', such as
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a \gls{RASA} ``\gls{telescope}'' (See: \gls{astrograph}).
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The primary concern is the lack of \gls{satellite}
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tracking mounts, because \gls{telescope} mounts are generally too slow,
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and need to ``leap frog'' the \gls{satellite}. \Glspl{rotator} used for \glspl{antenna}
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aren't typically stable enough for a camera.
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