  The Large Array Survey Telescope (LAST) is a wide-field telescope designed to
explore the variable and transient sky with a high cadence and to be a test-bed
for cost-effective telescope design. A LAST node is composed of 48 (32 already
deployed), 28-cm f/2.2 telescopes. A single telescope has a 7.4 deg^2 field of
view and reaches a 5-sigma limiting magnitude of 19.6 (21.0) in 20s (20x20s)
(filter-less), while the entire system provides a 355 deg^2 field of view. The
basic strategy of LAST is to obtain multiple 20-s consecutive exposures of each
field (a visit). Each telescope carries a 61 Mpix camera, and the system
produces, on average, about 2.2 Gbit/s. This high data rate is analyzed in near
real-time at the observatory site, using limited computing resources (about 700
cores). Given this high data rate, we have developed a new, efficient data
reduction and analysis pipeline. The data pipeline includes two major parts:
(i) Processing and calibration of single images, followed by a coaddition of
the visit's exposures. (ii) Building the reference images and performing image
subtraction and transient detection. Here we describe in detail the first part
of the pipeline. Among the products of this pipeline are photometrically and
astrometrically calibrated single and coadded images, 32-bit mask images
marking a wide variety of problems and states of each pixel, source catalogs
built from individual and coadded images, Point Spread Function (PSF)
photometry, merged source catalogs, proper motion and variability indicators,
minor planets detection, calibrated light curves, and matching with external
catalogs. The entire pipeline code is made public. Finally, we demonstrate the
pipeline performance on real data taken by LAST.
