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Yayın Design of the near infrared camera DIRAC for East Anatolia Observatory(SPIE, 2022) Zhelem, Ross; Content, Robert; Churilov, Vladimir; Kripak, Yevgen; Waller, Lew; Case, Scott; Mali, Slavko; Muller, Rolf; Gonzalez, Mario; Adams, Dave; Binos, Nick; Chin, Timothy; Farrell, Tony; Klauser, Urs; Kondrat, Yuriy; Kunwar, Nirmala; Lawrence, Jon; Lorente, Nuria; Luo, Summer; McDonald, Erica; McGregor, Helen; Nichani, Vijay; Pai, Naveen; Vuong, Minh; Zahoor, Jahanzeb; Zheng, Jessica; Norris, Barnaby; Bryant, Julia; Vaccarella, Annino; Herrald, Nick; Gilbert, James; Yeşilyaprak, Cahit; Güçsav, Bülent; Coker, Deniz; Keskin, Onur; Jolissaint, LaurentThe 4m DAG telescope is under construction at East Anatolia Observatory in Turkey. DIRAC, the " DAG InfraRed Adaptive optics Camera", is one of the facility instruments. This paper describes the design of the camera to meet the performance specifications. Adaptive and auxiliary optics relay the telescope F/14 input 1:1 into DIRAC. The camera has an all refractive design for the wavelength range 0.9 - 2.4 micron. Lenses reimage the telescope focal plane 33 x 33 as (9 x 9 mm) on a 1k x 1k focal plane array. With magnification of 2x, the plate scale on the detector is 33 mas/pixel. There are 4 standard filters (Y, J, H, K) and 4 narrowband continuum filters. A 12 position filter wheel allows installation of 2 extra customer filters for specific needs; the filter wheel also deploys a pupil viewer lens. Optical tolerancing is carried out to deliver the required image quality at polychromatic Strehl ratio of 90% with focus compensator. This reveals some challenges in the precision assembly of optics for cryogenic environments. We require cells capable of maintaining precision alignment and keeping lenses stress free. The goal is achieved by a combination of flexures with special bonding epoxy matching closely the CTE of the lens cells and crystalline materials. The camera design is very compact with object to image distance <220 mm and lens diameters <25 mm. A standalone cryostat is LN2 cooled for vibration free operation with the bench mounted adaptive optics module (TROIA) and coronagraph (PLACID) at the Nasmyth focus of the DAG telescope.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 Dogu Anadolu Gözlemevi (DAG) integrated dome and telescope on-site assembly(SPIE, 2024) Marchiori, Gianpietro; Rampini, Francesco; Amalfi, Manfredi; Bressan, Riccardo; Ghedin, Leonardo; Battistel, Cristina; Manfrin, Cristiana; Vio, L.; Niero, Tiziano; Marchiori, Tommaso; Pirnay, Olivier; Gabriel, Eric; Méant, Laurence; Yeşilyaprak, Cahit; Keskin, OnurThe Dogu Anadolu Gözlemevi (DAG) Eastern Anatolia Observatory is an astronomical project fully funded by Turkish Ministry of Development and the Atatürk University of Astrophysics Research Telescope (ATASAM). DAG Observatory will be provided with a 4m-class optical and infrared telescope, equipped with secondary (0.76m) and tertiary mirrors which furnish the telescope with two Nasmyth foci. Since 2015, the project has seen the crucial contribution of EIE GROUP in the Design, Production and on-site Installation of the 4m class optical/near-infrared telescope (DAG Telescope) in contract with AMOS company. EIE GROUP is also the main contractor of the 18.6m-diameter Rotating Building (DAG Dome) at an altitude of 3170m asl on the Erzurum Plateau, Turkey. The telescope was completely pre-assembled and successfully tested at the Integration Area Facilities of the EIE GROUP. Subsequently disassembled and transported to the final installation site. Despite the serious effects of the pandemic, the EIE GROUP, in agreement with its final Customer, has adopted a telescope assembly strategy integrated with the final assembly phases of the Dome. This allowed EIE to mount the entire telescope, in a single summer season, in total safety (thanks to the special measures adopted). This paper focuses on the development of this on-site assembly EIE activities of DAG Telescope, which at present have exceeded the 95% of completion. The main critical issues and related engineering solutions will be analyzed, with emphasis on both managerial and erection approaches adopted by EIE GROUP for this integrated phase of the project completion.Yayın DAG (Dogu Anadolu Gozlemevi) telescope mount performances(SPIE, 2024) Marchiori, Gianpietro; Rampini, Francesco; Amalfi, Manfredi; Bressan, Riccardo; Ghedin, Leonardo; Battistel, Cristina; Manfrin, Cristiana; Vio, L.; Niero, Tiziano; Marchiori, Tommaso; Pirnay, Olivier; Gabriel, Eric; Méant, Laurence; Yeşilyaprak, Cahit; Keskin, OnurThe DAG (Dogu Anadolu Gözlemevi) Eastern Anatolia Observatory is an astronomical project fully funded by Turkish Ministry of Development and the Atatürk University of Astrophysics Research Telescope (ATASAM). DAG Observatory is provided with a 4m-class optical and infrared telescope, equipped with secondary (0.76m) and tertiary mirrors which furnish the telescope with two Nasmyth foci. Since 2015, the project has seen the crucial contribution of EIE GROUP in the Design, Production and on-site Installation of the mount structure of the 4m class optical/near-infrared telescope (DAG Telescope) in contract with AMOS company. EIE GROUP is also the main contractor of the 18.6m-diameter Rotating Building (DAG Dome) at an altitude of 3170m asl on the Erzurum Plateau, Turkey. After completing a full assembly and testing in the factory, the telescope was subsequently disassembled and transported to the final installation site. Now, on-site assembly activities have been completed, and all internal acceptance tests regarding the mount structure have been conducted. This document focuses on the on-site assembly activities of the EIE Group, as well as the related internal pre-commissioning, commissioning, and functional and acceptance tests.Yayın DAG rotating enclosure final erection and acceptance tests(SPIE, 2024) Marchiori, Gianpietro; Rampini, Francesco; Amalfi, Manfredi; Bressan, Riccardo; Ghedin, Leonardo; Battistel, Cristina; Manfrin, Cristiana; Vio, L.; Niero, Tiziano; Marchiori, Tommaso; Yeşilyaprak, Cahit; Keskin, OnurThe DAG (Dogu Anadolu Gözlemevi) observatory is the largest observatory in Turkey and is composed by the 4m-class infrared Telescope, the Rotating Enclosure, the dome fixed structure and the auxiliary building. It is mounted on the top of Karakaya Mountain at 3170m altitude, close to Erzurum, in Turkey. This presentation refers to the DAG Rotating Enclosure. The Rotating Enclosure is octagonal sized steel structure with eight trolleys acting on a rai of 18.6 meters diameter. The structure is and 14.5m high over a pillar 9.0m. It is equipped with an observing slit door composed by two L-Shaped elements. Six sliding ventilation doors, about 3.7x6.5m each, that can be opened independently and with different degrees of aperture allow for optimizing the internal airflow. Immediately Inside the observing slit doors, there is a windscreen consisting of 3 panels that, in case of wind, are raised in accordance with the telescope elevation to protect it. The panels have a specific degree of air permeability to still allow ventilation for the telescope. A 6.5tons overall bridge crane allows to move pieces in every zone of the rotating enclosure for the maintenance of the telescope optics. At the beginning of November 2023, EIE carried out all acceptance tests with the end customer and delivered the rotating enclosure to ATASAM. This paper provides the results of the final erection and reports the procedures and results of the Acceptance Tests performed by EIE for the DAG Rotating Enclosure activities. 4m class telescopes and related Domes represent nowadays a consolidated part of EIE core-business, a low costs standard product able to satisfy the most critical observational requirements of astronomers.Yayın DAG telescope first light commissioning status(SPIE, 2024) Yeşilyaprak, Cahit; Keskin, Onur; Güçsav, Bülent; Öztürk Cetni, Derya; Kuruçolak, MehmetDAG, the 4-meter VIS/NIR telescope and the observatory, reached foreseen first light status at last: the enclosure acceptance is completed; to finalize the opto-mechanical alignment and pointing/tracking, the telescope mirrors have been exposed to heavens in absence of instrumentation. On the optical train; the two instruments that make the telescope distinctive, namely KORAY (the optical derotator) and flexible concept TROIA (ExAO) systems are characterized at the laboratory, and are anxiously waiting to be installed at their blessed location of mission - the diffraction limited Nasmyth platform along with the PLACID stellar coronagraph and DIRAC (NIR camera). We felt that PLACID, which is not yet lead star got jealous; so with the funding provided by the RACE-GO (ERC Project), within just after 60 days of its first mission, it will undergo for a technical makeover to a K-Band instrument. We now have a dilemma, the vacant seeing Nasmyth platform - the landlord- is still waiting for a cutting-edge tenant. Thus, the paper not only presents the telescope and its instrumentation, but also reserves a dedicated section for possible co-operations/collaborations to take place on the seeing Nasmyth platform.
