Yazar "Keskin, Onur" seçeneğine göre listele
Listeleniyor 1 - 20 / 51
Sayfa Başına Sonuç
Sıralama seçenekleri
Yayın Adaptive backstepping approach for 2-DOF telescopes despite unknown wind disturbance(Institute of Electrical and Electronics Engineers Inc., 2019-07) Ünal, Ali Cem; Yılmaz, Cemal Tuğrul; Kararsız, Gökhan; Keskin, Onur; Yeşilyaprak, CahitSmall ground telescopes on the marked are widely used in many space observatories and scientific researches. There are three main problems in such telescopes; positioning of the focal point and the need of tuning for both different seasonal wind speeds and mass changes of the telescope arm. This study focuses on eliminating those problems for 2-DOF altazimuth configuration small telescopes. An adaptive controller is designed to create a set and forget system. The mathematical model of the telescope is derived based on RR type joint configuration. For a realistic approach, motor dynamics is considered in the mathematical model. The wind disturbance is modeled according to the Wind-Gust model which is a sum of sinusoidal with unknown amplitude, frequency and phase. The controller aims to cancel the effect of the disturbance on focal point of the telescope while positioning. The asymptotic stability is proven with the Lyapunov approach. The numerical study is illustrated to success of the proposed controller.Yayın Adaptive optics for DAG telescope(Türk Astronomi Derneği, 2020-12-11) Keskin, Onur; Jolissaint, LaurentWhat we propose for DAG is therefore a natural guide star GLAO system, that can be turned into a highly efficient AO system. Thus the working principle and expected performance analysis will be shown. In this manner most DAG users will be able to make some use of the DAG AO. Later, it will be possible to upgrade the system by changing th algorithm and adding 1 or 2 additional DM, and even laser guide stars.Yayın Advances for the 4m DAG Telescope in Flange derotator(SPIE, 2020-12-13) Keskin, Onur; Ünal, Ali Cem; Koç, İlker Murat; Jolissaint, Laurent; Yeşilyaprak, CahitThe purpose of this study is expressing advances in design stages for in flange optical field derotator system for 4 meters DAG Telescope. In-Flange Derotator KORAY (K-mirror OpticalRelAY) is designed, analysed and manufactured to meet the specifications of DAG telescope. DAG telescope, situated at Erzurum/Karakaya summit at 3150m altitude, is the first Turkish optical telescope with VIS(Visible) and IR (Infrared) observation capability. DAG, designed by Turkish engineers at FMV Isik University, is also the largest telescope (4m diameter) in Turkey and in European continent. Being one of the 2023 vision projects; the first light of DAG is expected to take place in 2021. This purpose brings some real-life challenges such as design limitations, material selection and electronic integration.Yayın Agile development approach for the observatory control software of the DAG 4m telescope(SPIE, 2016) Güçsav, Bülent Burak; Çoker, Deniz; Yeşilyaprak, Cahit; Keskin, Onur; Zago, Lorenzo; Yerli, Sinan KaanObservatory Control Software for the upcoming 4m infrared telescope of DAG (Eastern Anatolian Observatory in Turkish) is in the beginning of its lifecycle. After the process of elicitation-validation of the initial requirements, we have been focused on preparation of a rapid conceptual design not only to see the big picture of the system but also to clarify the further development methodology. The existing preliminary designs for both software (including TCS and active optics control system) and hardware shall be presented here in brief to exploit the challenges the DAG software team has been facing with. The potential benefits of an agile approach for the development will be discussed depending on the published experience of the community and on the resources available to us.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 Coordination in building an observatory: A case study of Eastern Anatolian Observatory (DAG)(SPIE-Int Soc Optical Engineering, 2018) Şahmalı, Ali Erkan; Yeşilyaprak, Cahit; Keskin, OnurEastern Anatolian Observatory (DAG) is designed to build on one of the summits of Palandoken Mountains in Erzurum, Turkey, at an altitude of 3,151 meters. The building is under construction since 2015 and expected to be completed in 2020. The building is designed as an integrated building, having operational departments, services, mechanical and electrical infrastructure for observations as well as cleaning and coating units, adjacent to the main observatory building. As one might expect this integration creates serious coordination problems between architect, engineers, telescope, enclosure, and cleaning & coating unit manufacturers. The construction progress of the investment is almost 20%. There are quite an amount of "lessons learned" in this period, and need to be developed by the parties, for their existing and future works. The building has so many challenges such as geological and geographical limitations, environmental and meteorological constraints, engineering and structural considerations, energy efficiency and sustainability, materials used and their performances at these limitations.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 4m telescope: assembly, integration and testing(SPIE-Int Soc Optical Engineering, 2018-07-06) Pirnay, Olivier; Lousberg, Grégory P.; Gabriel, Eric; Marchiori, Gianpietro; Busatta, Andrea; Yeşilyaprak, Cahit; Keskin, OnurAMOS with EIE as a main subcontractor, was awarded a contract in November 2014 for the design, manufacturing and installation of a 4m-class telescope for the Turkish Eastern Anatolia Observatory (DAG) situated at 3170 m above the sea level in Palandöken mountains. The telescope is based on a Ritchey-Chretien configuration with two folded Nasmyth focal planes and a focal length of 56m. Diffraction-limited performances will be reached thanks to the combination of the active optics system and the adaptive optics system that will be implemented on one of the Nasmyth ports. The active optics system aims at controlling the shape of the primary mirror by means of 66 axial force actuators and positioning actively the secondary and tertiary mirrors by means of hexapods. More than 30 years of experience in testing instruments and telescopes, including optical testing, alignment, metrology, mechanical static and dynamic measurements, system identification, etc. allow to implement an adequate verification strategy combining component level verifications with factory and site test in the most efficient and reliable manner. As a main contractor, AMOS is in charge of the overall project management, the system engineering, the optical design and the active optics development. As a main sub-contractor and partner of AMOS, EIE is in charge of the development of the mount. The factory test therefore takes place in EIE premises. In this paper is shortly presented the overall design of the telescope with a review of the specification, the optical design and a description of the major sub-systems, including the optics. The assembly, integration et test plan is outlined. The assembly sequence and the tests of the active optics and the mount are discussed. Finally, the site integration and tests are explained. The process to assess the image quality of the telescope and the verification instrument developed for this purpose by AMOS are presented.Yayın DAG 4m telescope: optics completion, on-site integration and test(SPIE, 2022) Pirnay, Olivier; Albart, Pierre; Bastin, Christian; De Ville, Jonathan; Gabriel, Eric; Leseur, Thibault; Lousberg, Grégory P.; Méant, Laurence; Orban, Sabrina; Tortolani, Jean-Marc; Amalfi, Manfredi; Marchiori, Gianpietro; Rampini, Francesco; Busatta, Andrea; Yeşilyaprak, Cahit; Keskin, OnurAMOS with EIE as main subcontractor has recently completed the erection of the 4 m telescope located at the Turkish Eastern Anatolia Observatory (DAG) set up by the Ataturk University Astrophysics Research and Application Centre (ATASAM) of Erzurum. The telescope design is based on a Ritchey-Chrétien configuration with two folded Nasmyth focal planes and a focal length of 56m. The optical train is composed of three mirrors: the primary mirror (M1) with an optical aperture of 4m, a convex secondary mirror (M2), and a large flat folding mirror (M3). Diffraction-limited performances in optical and near infrared spectral bands will be achieved thanks to the combination of active and adaptive optics systems. The active optics system is controlling the shape of the primary mirror by means of 66 axial force actuators and position actively the secondary and tertiary mirrors by means of hexapods. The adaptive optics system will be implemented at one of the two Nasmyth ports. As main contractor, AMOS is in charge of the overall project management, the system engineering, the optical design and the active optics development. As main sub-contractor and partner of AMOS, EIE is in charge of the development of the mount. Following the factory acceptance in Europe, the telescope was dismounted and delivered in early 2021. The activities onsite were carried out according to the assembly, integration and verification plan (AIV plan). In the meantime, the fabrication of the 4 m primary mirror was completed, and the full set of mirrors was forwarded on-site before the end of the year 2021. In this paper is presented a brief description of the design and performances of the telescope followed by the project progress status at the time the optics are being integrated in the telescope for the first time. This includes the review of the mirrors as-built quality and the excepted performances of the telescope mount after alignment and tuning. The path forward final acceptance is explained with the presentation of the optical alignment method and the test carried-out on-sky.Yayın DAG odak düzlemi araçları - hedefler ve seçenekler(Türk Astronomi Derneği, 2020-12-11) Yerli, Sinan Kaan; Yeşilyaprak, Cahit; Keskin, Onur; Güver, TolgaDAG projesi çerçevesinde, teleskobun da tanımlanması ve optiğinin belirlenmesinden sonra Türk Astronomisinin gereksinim ve gelecek hedefleri de gözetilerek proje ekibi DAG teleskobunun iki Nasmyth odağına yerleştirilecek olası tayfölçer ve görüntüleme araçları için öngörülerde bulunmuş ve yeni bir proje teklifi vermiştir. Bu bildiride bu süreç tanıtılıp sunulan yeni proje tanıtılacaktır.Yayın The DAG project and its management(Türk Astronomi Derneği, 2020-12-11) Zago, Lorenzo; Keskin, OnurThe DAG Project and managerial issues related to call for tenders, determination of technical specifications both for the telescope, the dome and the observatory building 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 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.Yayın DAG telescope site studies and infrastructure for possible international co-operations(SPİE-INT Soc Optical Engineering, 2016) Yerli, Sinan Kaan; Yeşilyaprak, Cahit; Keskin, Onur; Aliş, SinanThe selected site for the 4 m DAG (Eastern Anatolian Observatory in Turkish) telescope is at "Karakaya Ridge", at 3170 m altitude (3150 m after summit management). The telescope's optical design is performed by the DAG technical team to allow infrared observation at high angular resolution, with its adaptive optics system to be built in Turkey. In this paper; a brief introduction about DAG telescope design; planned instrumentation; the meteorological data collected from 2008, clear night counts, short-term DIMM observations; current infrastructure to hold auxiliary telescopes; auxiliary buildings to assist operations; the observatory design; and coating unit plans will be presented along with possible collaboration possibilities in terms of instrumentation and science programs.Yayın DAG türbülans jeneratörü(Türk Astronomi Derneği, 2020-12-11) Özbaldan, Emrah Emin; Kılıçerkan Başlar, Gamze; Başlar, İsmail; Keskin, Onur; Yeşilyaprak, CahitDoğu Anadolu Gözlemevi (DAG) projesi kapsamında; teleskop için gereken ve zorunlu olan Adaptif Optik (AO) sisteminin kontrol sistemlerinin geliştirilmesi, performansı ve ön testlerinin gerçekleştirileceği, atmosferik olarak yapay koşulların oluşturulup deneneceği, gerekli olan Optik Test Laboratuvarı oluşturulmasının ilk ve temel adımı, DAG Türbülans Jeneratörü ile sağlanacaktır. Optik laboratuvar için olmazsa olmaz olan ekipman tarafımızca üretilecektir. Proje kapsamında tarafımızca üretilecek bu jeneratörün temel malzemeleri noktasal kaynaklı lazer, CCD kamera, optik komponentler ve bazı elektronik kartlardır. Bu laboratuvar ve kurulacak sistem sayesinde; öncelikle DAG projesi kapsamındaki AO sisteminin ilk testlerinin yapılması planlanmaktadır.Yayın DAG-SLODAR (SLOpe Detection And Ranging) Teleskobu(Türk Astronomi Derneği, 2020-12-11) Şatır, Onur; Yeşilyaprak, Cahit; Keskin, OnurAtmosferin astronomik gözlemlere olan olumsuz etkilerini alt etmek üzere geliştirilmiş ve DAG teleskobunda da kullanılacak olan Adaptif Optik (AO) sistemleri, türbülansın ayrıntılı bir şekilde karakterize edilmesine ihtiyaç duyar. SLODAR, atmosferik optik türbülansın dikey profilini, iki yakın yıldızın Shack-Hartmann dalgacephesi algılayıcısı (SH-WFC) ile yapılan dalgacephesi eğimi ölçümlerinin çapraz korelasyonundan elde eden bir yöntemdir. SLODAR sistemi, küçük çaplı (?50cm) bir teleskobun odak düzlemine yerleştirilen, iki SH-WFC barındıran SLODAR aygıtından oluşur. Paranal, La Palma, Mauna Kea ve SAAO gözlemevlerinde kurulan SLODAR teleskopları "yer katmanı (ground layer)" olarak adlandırılan ve yerleşkenin üzerindeki ilk kilometre içindeki türbülansı ölçmek amacıyla kullanılmışlardır. Bu sunumda DAG yerleşkesinde kurulmakta olan SLODAR sisteminden bahsedilecektir.Yayın DAG-TGI: türbülans jeneratörü kalibrasyonu(Türk Astronomi Derneği, 2020-12-11) Tezcan, Cihan Tuğrul; Akbulak, Ümit Bora; Güvenir, Furkan; Aydemir, Ömer Faruk; Keskin, Onur; Yeşilyaprak, CahitDAG (Doğu Anadolu Gözlemevi) 4-metre birincil ayna ile aktif (aO) ve adaptif (AO) optik sistemlerine sahiptir. DAG’ın odak düzlemi aletlerinin geliştirilmesi ve kurulması için, türbülans şartlarını canlandırabilen bir türbülans jeneratörü geliştirilmiştir. Bu çalışmada jeneratör kalibrasyonu ve karakterizasyonu sağlanmıştır. Türbülans jeneratörü temel olarak soğuk hava ile kontrol edilebilen sıcak havanın gene kontrol edilebilen rüzgar şartlarında karıştırılarak türbülans oluşturmasıdır. Bu çalışma ileride DAG’ın adaptif optik sisteminin simülastonu olacaktır.Yayın DAG-TGI: Turbulence generator instrument for DAG (Eastern Anatolia Observatory)(SPIE-Int Soc Optical Engineering, 2018-07-18) Yeşilyaprak, Cahit; Keskin, Onur; Akbulak, Ümit Bora; Tezcan, Cihan Tuğrul; Güvenir, Furkan; Aydemir, Ömer FarukDAG (East Anatolia Observatory) Telescope has 4 m mirror with active optics (a0) and adaptive optics (AO) systems. In order to evaluate DAG's focal plane instruments and their installation, calibration and laboratory performance, one must emulate the atmospheric turbulence condition on DAG site. Although atmospheric conditions of the site are gathered from various meteorological and astronomical instruments, a turbulence generator instruments (TGI) is designed and characterized to emulate the similar characteristics. The design of the TGI is based on the forcing of cold air and temperature controllable hot air at adjustable wind speeds within a confined chamber, where the atmospheric turbulence strength is altered. First results of the TGI have been presented in this article for DAG's AO system.Yayın DAG: A new observatory and a prospective observing site for other potential telescopes(SPIE, 2016) Yeşilyaprak, Cahit; Yerli, Sinan Kaan; Keskin, Onur; Güçsav, Bülent BurakDAG (Eastern Anatolia Observatory is read as "Dogu Anadolu Gözlemevi" in Turkish) is the newest and largest observatory of Turkey, constructed at an altitude of 3150 m in Konakll/Erzurum provenience, with an optical and nearinfrared telescope (4 m in diameter) and its robust observing site infrastructure. This national project consists of three main phases: DAG (Telescope, Enclosure, Buildings and Infrastructures), FPI (Focal Plane Instruments and Adaptive Optics) and MCP (Mirror Coating Plant). All these three phases are supported by the Ministry of Development of Turkey and funding is awarded to Atatürk University. Telescope, enclosure and building tenders were completed in 2014, 2015 and 2016, respectively. The final design of telescope, enclosure and building and almost all main infrastructure components of DAG site have been completed; mainly: road work, geological and atmospheric surveys, electric and fiber cabling, water line, generator system, cable car to summit. This poster explains recent developments of DAG project and talks about the future possible collaborations for various telescopes which can be constructed at the site.
- «
- 1 (current)
- 2
- 3
- »
