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 deg² field of view and reaches a 5σ limiting magnitude of 19.6 (21.0) in 20 (20 × 20) s (filter-less), while the entire system provides a 355 deg² 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⁻¹. 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 LAST 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 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.

中文翻译：

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大型阵列巡天望远镜——管道。一、基本图像缩减和访问添加

大型阵列巡天望远镜 (LAST) 是一款宽视场望远镜，旨在以高节奏探索多变和瞬变的天空，并成为具有成本效益的望远镜设计的测试平台。一个 LAST 节点由 48 个（已部署 32 个）、28 cm 组成F/2.2望远镜。单个望远镜的视场角为 7.4 度²，达到 5σ20 (20 × 20) 秒（无滤镜）内的极限星等为 19.6 (21.0)，而整个系统提供 355 deg ²视场。LAST的基本策略是获得每个字段的多个20 s连续曝光（一次访问）。每个望远镜携带一个 61 Mpix 相机，系统平均产生约 2.2 Gbit s ^-1。观测站使用有限的计算资源（约 700 个核心）近乎实时地分析如此高的数据速率。鉴于如此高的数据速率，我们开发了一种新的、高效的数据缩减和分析管道。LAST 数据管道包括两个主要部分：(i) 单幅图像的处理和校准，然后添加访问的曝光。(ii) 构建参考图像并执行图像减法和瞬态检测。这里我们详细描述管道的第一部分。该管道的产品包括经过光度和天体测量校准的单个和复合图像、标记每个像素的各种问题和状态的 32 位掩模图像、从单个和复合图像构建的源目录、点扩散函数光度测定、合并源目录、自行和变异性指示器、小行星检测、校准光变曲线以及与外部目录的匹配。整个管道代码是公开的。最后，我们在 LAST 获取的实际数据上演示了管道性能。