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File extensions, FITS

glossary
Jeff Moe 2022-09-04 13:19:10 -06:00
parent a0610a7f7b
commit a80fac60d2
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src/Glossary.tex
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% network
% noise
% workstation
% mean
% standard deviation
% max
% timestamp
% frame

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src/SNOUG.tex
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@ -361,7 +361,7 @@ leftmargin=1cm,rightmargin=1cm
\chapterconf{Solve}{Plate Solvers}{Place from Pixels}
\chapterconf{Detect}{Detect}{Find Satellites}
\chapterconf{Identify}{Identify}{More Than Just Old Rocket Bodies}
\chapterconf{Upload}{Upload}{Send Data to the SatNOGS Network}
\chapterconf{Upload}{Upload \& Share}{Send Data to the SatNOGS Network}
\chapterconf{Support}{Support}{Help!}
\chapterconf{Contact}{Contact}{Email, Chat, Forum}
%% END MAINMATTER CHAPTERS %%%

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src/Upload.tex
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% International Public License (CC BY-SA 4.0) by Jeff Moe.
%
\section{Upload Data}
\section{Push Data Upstream}
\label{sec:upload}
\index{upload}
Push.
The \gls{SatNOGS} network isn't ready for optical data yet.
So there is nothing that can be uploaded. This is under
development.
\section{File Extensions}
\label{sec:upload-extensions}
\index{formats}
The following file extensions are in use:
\begin{mdframed}[backgroundcolor=blue!10,linecolor=blue!30]
\begin{description}
\item [.cal] --- Cal % XXX
\item [.cat] --- Cat % XXX
\item [.csv] --- \gls{CSV}
\item [.dat] --- Data.
\item [.fits] --- \gls{FITS}.
\item [.png] --- \gls{PNG}.
\end{description}
\end{mdframed}
\index{FITS}\index{PNG}\index{CSV}
\section{Data Files}
\label{sec:upload-data}
\index{data}\index{stvid}\index{process}\index{acquire}
After the \texttt{stvid} acquisition and processing steps have been
run, files such as below will be generated:
\begin{minted}{sh}
2022-08-23T04:16:26.633.fits
2022-08-23T04:16:26.633.fits.cal
2022-08-23T04:16:26.633.fits.cat
2022-08-23T04:16:26.633.fits.png
2022-08-23T04:16:26.633_48473_catalog.dat
2022-08-23T04:16:26.633_48473_catalog.png
2022-08-23T04:16:26.633_52718_catalog.dat
2022-08-23T04:16:26.633_52718_catalog.png
2022-08-23T04:16:26.633_90000_unid.dat
2022-08-23T04:16:26.633_90000_unid.png
2022-08-23T04:16:26.633_hough.csv
2022-08-23T04:16:26.633_predict.csv
2022-08-23T04:16:26.633_threshold.csv
\end{minted}
\subsection{\texttt{.fits} FITS Files}
\gls{FITS} files are the main files created during acquisition and
are the main files used in processing. It has the data of
the actual image taken with the camera. FITS files will be significantly
larger than the other files, at around 35 megabytes each, depending
on sample rate and frame size.
\index{FITS}\index{acquire}\index{process}
The \texttt{stvid} program creates it's customized \gls{FITS} format
file, which is a stack up of multiple images.
I'll leave explanation of the \texttt{stvid} \gls{FITS} file structure
to the program's author, Cees Bassa:
\begin{quote}
With stvid, I typically store 10 seconds worth of video frames, 100 frames at 10 \gls{Hz} frame rate or 250 frames at 25 \gls{Hz} frame rate into a so-called ``four frame''. Here, for each pixel of the initial 100 or 250 frames, the mean, standard deviation, maximum and argmax are stored, each as its own frame. Objects that move will stand out because they will have a high (max - mean) / standard deviation, which allows me to detect trails. Once a trail is detected, the argmax frame tells me the frame number and hence the motion of the trail, and using the timestamps of the individual 100 or 250 frames, I can reconstruct the pixel position as a function of time during the 10 second exposure, using only 4 frames instead of the 100 or 250 individual video frames.
\end{quote}
\index{Bassa, Cees}