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Yayın Integrated opto-dynamic modeling of the 4-m DAG telescope image quality performance(SPIE-Int Soc Optical Engineering, 2016) Zago, Lorenzo; Guex, Benjamin; Yeşilyaprak, Cahit; Yerli, Sinan Kaan; Keskin, OnurThe Turkish DAG 4-m telescope is currently through the final design stage. It is to be located on a 3170 m mountain top in Eastern Anatolia. The telescope will be a state-of-The art device, alt-Az mount with active primary and adjustable secondary and tertiary mirrors. Its optics design is specially aimed at being compatible with advance adaptive optics instrumentation. The ultimate performance of such a telescope results of multiple concurrent effects from many different components and active functions of the complex system. The paper presents a comprehensive integrated (end-To-end) model of the telescope, comprising in one computational sequence all structural, electrodynamics and oactive optics performance that produce the image quality at the focal plane. The model is entirely programmed in Matlab/Simulink and comprises a finite element model of structure and mirrors, dynamics modal reduction, deformation analyses of structural and optical elements, active optics feedback control in the Zernike modal space.Yayın Status of the Focal Plane Instrumentation (FPI) Project of the 4 m DAG Telescope(SPIE, 2016-08-09) Keskin, Onur; Yerli, Sinan Kaan; Yeşilyaprak, Cahit; Güver, Tolga; Aliş, Sinan; Yelkenci, Filiz Korhan; Güçsav, Bülent Burak; Arabacı, Mehtap Özbey; Erol, AyşeDAG (Eastern Anatolia Observatory in Turkish) will be the newest and largest (4m) observatory of Turkey in both optical (VIS) and near-infrared (NIR) Owith its robust observing site infrastructure. The telescope is designedOto house 2 Nasmyth platformes which will be dedicated to NIR and VIS observations. A collaboration has recently been established among four Turkish universities including FMV Isik University (for adaptive optics systems), Middle East Technical University (fort measurement, test and calibration purposes), Istanbul University (for new technology instruments, e.g. MKIDs) and as the coordinator Ataturk University (for obtaining NIR and VIS instruments). In this paper the status of the recently approved FPI project and its aims are presented and possible collaboration opportunities are emphasized.Yayın TROIA adaptive optics system for DAG Telescope(SPIE, 2020-12-13) Keskin, Onur; Jolissaint, Laurent; Bouxin, Audrey; Yeşilyaprak, CahitThis paper presents the specifications of TROIA-TuRkish adaptive Optics system for Infrared Astronomy system, the science rationale for these specifications, and description of the site technical and environmental conditions to be taken into account in the adaptive optics (AO) system design for the Eastern Anatolia Observatory-DAG telescope. With it's 468 actuators, EMCCD camera, and the pyramid wavefront sensor configuration; TROIA is able to adapt the degree of correction to a given guide star (GS) brightness during observations. The high actuator density of TROIA AO system will allow DAG to perform astronomical observations at ExAO performances.Yayın TROIA Adaptive optics system for DAG telescope; assembly and laboratory performance prior to on-sky assessment(SPIE, 2022-08-29) Keskin, Onur; Jolissaint, Laurent; Bouxin, Audrey; Yeşilyaprak, CahitIn this article, we describe the current status of the development of TROIA* a pyramid wavefront sensor based adaptive optics system designed for DAG, a new 4 m telescope located in Eastern Anatolia, Turkey. The wavefront uses a no-noise electron-multiplied CCD camera, and the deformable mirror has a large actuators density, allowing coronagraphic science in one hand, but also system optimization for low light level or bad seeing conditions thanks to the versatility of the P-WFS. We describe the optical design, the mounting and alignment procedure and our loop control concept. Closed loop results are described, showing that while there are still many issues to fix before the sky version, the system behaves as expected.Yayın Auxiliary free space optical communication project to ensure continuous transfer of data for DAG the 4m telescope(SPIE, 2016) Keskin, Onur; Yeşilyaprak, Cahit; Yerli, Sinan KaanThe continuity of the amount of data that the 4m DAG (Eastern Anatolia Observatory in Turkish) telescope will produce and transfer to Ataturk University is critical not to jeopardize the science programs. Though the fiber optics and radio link infrastructures are in place, these systems are still volatile against earthquakes, and possible excavation damages. Thus the 4m DAG telescope will be equipped with a free space optical communication system to ensure the continuity of the data transfer as a backup system. In order to cope with the disturbances introduced by the atmospheric turbulence, the transceiver FSO system will be equipped with a wavefront corrector. In this paper, the Cassegrain optical design, and working principle of this system as well as expected performance analyses will be presented.Yayın Project management of DAG: Eastern Anatolia Observatory(SPIE, 2016) Keskin, Onur; Yeşilyaprak, Cahit; Yerli, Sinan Kaan; Zago, Lorenzo; Güver, Tolga; Aliş, SinanThe four meter DAG (Eastern Anatolia Observatory in Turkish) telescope is not only the largest telescope in Turkey but also the most promising telescope in the northern hemisphere with a large potential to offer scientific observations with its cutting edge technology. DAG is designed to be an AO telescope which will allow both infrared and visible observations with its two Nasmyth platforms dedicated to next generation focal plane instruments. In this paper, status updates from DAG telescope will be presented in terms of; (i) in house optical design of DAG, (ii) tender process of telescope, (iii) tender process of enclosure, and (iv) tender process of the observatory building. Also status updates from the focal plane instruments project and possible collaboration activities will be presented.Yayın Eastern Anatolia Observatory (DAG): Recent developments 2017(SPIE-INT Soc Optical Engineering, 2018-07-06) Yeşilyaprak, Cahit; Keskin, OnurEast Anatolia Observatory (DAG) is the new observatory of Turkey with the optical (VIS) and near-infrared (NIR) largest telescope (4 m mirror) and its robust observing site infrastructure. This national project consists of three phases with DAG (telescope, enclosure, building, infrastructure), FPI (Focal Plane Instruments and Adaptive Optics) and MCP (Mirror Coating Plant) and is supported by the Ministry of Development of Turkey. Almost all infrastructure (roads, geological and atmospheric surveys, electricity, fiber optics, water, generator, etc.) of DAG site (Erzurum/Turkey, 3170 m altitude) have been completed. The recent developments (telescope, enclosure, mirror, focal plane instruments, building, atmospheric studies, etc.) of DAG and its site in 2017 and 2018 were presented for the future possible collaborations for various astronomical instruments and telescopes which can be set up in DAG site.Yayın Eastern Anatolia Observatory (DAG): the status in 2022, towards the first light(SPIE, 2022) Yeşilyaprak, Cahit; Keskin, Onur; Jolissaint, LaurentEast Anatolian Observatory's DAG telescope, with its 4m diameter primary mirror and VIS/IR observation capability, Eastern Anatolian Observatory's 4m diameter class DAG telescope, with VIS/IR observation capability, will be located on the Konakll-Karaya summit at an altitude of 3170 m, near the city of Erzurum, Turkey. DAG contains both active optics (aO) and adaptive optics (AO) systems. With the enclosure assembly nearly done, and the dummy mirror integration including the M1 cell integration performed at the end of 2021; DAG telescope's AIV is planned to take place by the end of May/2022 and the Provisional Acceptance by November/2022. DAG is equipped with an in-flange derotator-KORAY (K-mirror Optical RelAY) that will direct the light to the seeing limited Nasmyth platform containing TROIA (TuRkish adaptive Optics system for Infrared Astronomy). The scientific instruments that DAG will receive in 2022, are but not limited to, a stellar coronagraph and a 30"NIR diffraction limited camera. In his paper, a global status update and expected optical performance characteristics will be presented.Yayın The DAG Project, a 4m class telescope: The telescope main structure performance(SPIE, 2016) Marchiori, Gianpietro; Busatta, Andrea; Ghedin, L.; Marcuzzi, Enrico; Manfrin, Cristiana; Battistel, C.; Pirnay, Olivier; Flebus, Carlo; Yeşilyaprak, Cahit; Keskin, Onur; Yerli, Sinan KaanDogu Anatolu Gözlemevi (DAG-Eastern Anatolia Observatory) Project is a 4m class optical, near-infrared Telescope and suitable enclosure which will be located at an altitude of 3.170m in Erzurum, Turkey. The DAG telescope is a project fully funded by Turkish Ministry of Development and the Atatürk University of Astrophysics Research Telescope - ATASAM. The Project is being developed by the Belgian company AMOS (project leader), which is also the optics supplier and EIE GROUP, the Telescope Main Structure supplier and responsible for the final site integration. The design of the Telescope Main Structure fits in the EIE TBO Program which aims at developing a Dome/Telescope systemic optimization process for both performances and competitive costs based on previous project commitments like NTT, VLT, VST and ASTRI. The optical Configuration of the DAG Telescope is a Ritchey-Chretien with two Nasmyth foci and a 4m primary thin mirror controlled in shape and position by an Active Optic System. The main characteristics of the Telescope Main Structure are an Altitude-Azimuth light and rigid structure system with Direct Drive Systems for both axis, AZ Hydrostatic Bearing System and Altitude standard bearing system; both axes are equipped with Tape Encoder System. An innovative Control System characterizes the telescope performance.Yayın Eastern Anatolia Observatory (DAG): The status in 2020(SPIE, 2020) Yeşilyaprak, Cahit; Keskin, OnurEast Anatolian Observatory's DAG telescope, with its 4m diameter primary mirror and VIS/IR observation capability, will be located on the Konakll-Karaya summit at an altitude of 3170 m, near the city of Erzurum, Turkey. Containing both active optics (aO) and adaptive optics (AO) systems, the first light for DAG is expected for the last quarter of 2021. DAG will be equipped with an in-flange derotator - KORAY (K-mirror Optical relAY) that will direct the light to the seeing limited Nasmyth platform containing TROIA (TuRkish adaptive Optics system for Infrared Astronomy). DAG first generation instruments will consist in a 30"FoV near-infrared (NIR) diffraction limited camera and a stellar coronagraph. In his paper, status updates from DAG telescope will be presented in terms of; (i) DAG site, (ii) Site infrastructure, (iii) current status of the observatory building, (iv) DAG optics, (v) current status of the telescope, (vi) current status of enclosure, (vi) current progress of the astronomical instruments, and (viii) status of the Optomechatronics Research Laboratory - OPAL.
