What's in the SMA raw data directory?

When taking interferometer data, the SMA records data in a set of files all contained in a single directory. Below is a description of the files you will find in your data directory. For a more complete description including data type, structure, and attributes, see Current SMA data file format [2021].

FILE NAME	DESCRIPTION
antennas	This file contains the X, Y and Z coordinates of each antenna, in meters. The coordinate system is defined, with these letters, in Thompson, Moran and Swenson's text "Interferometry and Synthesis in Radio Astronomy" (Chapter 4, page 87 in the 2nd Edition). This file is only written to once when the data directory is opened.
autoCorrelations	(SWARM only) This file contains the autocorrelation spectra from the SWARM correlator.
bl_read	This file contains the baseline information. There is one fixed-length record written per receiver per sideband per baseline per scan. The order of the loops writing out these records is: 'receiver, sideband, polarization, baseline'. For most tracks receiver and polarization only have a single value, and the loops collapse to 'sideband, baseline'
codes_read	The header blocks that comprise the header information for each scan generally only contain integer index 'code' values for the values. This file contains the associated string and description related to each code.
codeVersion	This file contains the dates at which certain critical pieces of the online software were compiled. It is intended to help track bug fixes that need to be applied to certain data sets.
eng_read	This file contains fixed-length records for engineering data - e.g. integration ID, pointing offsets. One record is written for each antenna.
in_read	This file contains scan header information e.g. source, project code, integration number, track ID, azimuth and elevation. It consists of fixed-length records, with one record written for each scan.
modeInfo	An ASCII file containing two integers on a single line. The first integer specifies the number of active receivers ("1" or "2"), the second integer specifies the bandwidth, in GHz ("2" or "4").
plot_me_5_rx{n}	There is one of these files for each active receiver. This file is is used by corrPlotter to produce the "mir display".
projectInfo_XXXX_XXX	For science files this will contain detailed information about the project (title, PI, projec code, type). This file assists with long term archiving and provides information about the nature of the data.
sch_read	This is the file that actually contains the visibility data. Unlike most of the files containing binary data, the records in this file are of wildly varying length, depending upon the resolution of the spectrometer band. There is one record written for each scan, and it contains the packed visibility data for all chunks and the pseudocontinuum channels.
spike_read	This file contains a list of the spikes identified and removed by the online spike removal system. The information is stored for the rare cases where spikes need to be restored.
sp_read	This file contains the header information for each individual spectral band of data. A spectral band can be either a correlator chunk or the pseudo-continuum channel.
SMAshLog_{YYYYMMDD_HHMMSS}	This file contains all of the SMAsh commands which were issued while the array was using this directory to store data. In some cases there may be more than one of these files in the directory.
sptsys_read	This file contains the spectral Tsys data - a new feature from 2020.
tsys_read	This file contains the system temperature information. It holds all the Tsys measurements we have for each antenna, along with the IF frequency ranges overwhich those Tsys measurements were acquired.
we_read	This file contains antenna status flags, and weather information for each scan. For the 11 element arrays, element 0 contains observatory-wide values, and the other elemets contain the values measured at the individual antennas.