We present the new design of the ATLAS unit (Asteroid Terrestrial-impact Last Alert System (see [1]) to be installed at Teide Observatory (TO) in Tenerife island (Spain), and the results of the ongoing tests of the first module (ATLAS-P). ATLAS-Teide, the 5th ATLAS unit, will be built by the IAC and will be operated as part of the ATLAS network in the framework of an operation and science exploitation agreement between the IAC and the UH. ATLAS-Teide will have a modular design based on commercial on the shelf (COTS) components. Each module will have an effective diameter of 56 cm, with a 7.3 deg2 field of view and a 1.26 "/pix plate scale. The new ATLAS modular design: An ATLAS module consists of four Celestron RASA 11 (a 28cm aperture, f/D=2.2) telescopes that point to the same sky field, equipped with QHY600PRO monochrome CMOS cameras that uses a SONY back-illuminated IMX-455 of 9576 x 6388 pixels of3.76 micron,in the prime focus.The systemis mounted on an equatorialL-550 Planewave Direct Drive mount ATLAS-P: The first ATLAS module was installed in November 2022 in an existing clamshell at the TO. This module (ATLAS-P) is being used as a prototype to test the system capabilities, develop the needed software (control, image processing, etc.) and complete the fully integration of ATLAS-Teide in the ATLAS network. Installed at TO, the ATLAS module prototype saw its first light on November 14, 2022. During its commissioning phase ATLAS-P demonstrated that fulfil all the mechanical, electronical and optical requirements. Frames obtained by combining 5x6s exposure time images done simultaneously with the 4 telescopes can easily detect V=20 mag asteroids. ATLAS-P is being used to design the software to operate the module in robotic mode and operate the 4 cameras simultaneously. The challenge of this modular design is the data management (reduction and storage). Each module has four cameras producing 120Mb images every few seconds. Those images have to be on-the-fly dark and flat reduced, aligned and combined before been analysed by the ATLAS software. A powerful GPU Linux based system is been under development and tested with ATLAS-P. We aim to have all the system ready when ATLAS-Teide be installed at Teide Observatory early 2024. ATLAS-Teide: ATLAS-Teide will consist of four ATLAS modules in a roll-off roof building. This configuration allows to cover almost the same sky area (30 deg2) of the other four telescopes (Wright Schmidt 50cm telescopes) of the ATLAS network already in operation. Acknowledgments: We acknowledge funding from the Spanish "Subprograma Estatal de Infraestructuras de Investigación y Equipamiento Científico Técnico (Ref. EQC2021-007122-P)".

[1] Tonry, J.L., et al. (2018). ATLAS: A High-cadence All-sky Survey System. Publications of the Astronomical Society of the Pacific, Volume 130, Issue 988, pp. 064505.