A New VLBI Station at Bosscha Observatory

A NEW VLBI STATION AT BOSSCHA OBSERVATORY Taufiq Hidayat1, Jinling Li2, Widjaja Martokusumo3, Hesti Wulandari1,Cong Liu2, Yuwei Liu2, M. Irfan1 1Bosscha Observatory and Department of Astronomy, Institut Teknologi Bandung (ITB), Indonesia 2Shanghai Astronomical Observatory, Chinese Academy of Sciences, China 3School of Architecture, Planning, and Policy Development, , Institut Teknologi Bandung (ITB), Indonesia The 10th International VLBI Technology Workshop (IVTW), October 21-25, 2025, Chalmers University of Technology, Onsala Space Observatory, Gothenburg, Sweden. OUTLINE ▪Introduction & Historical Background ▪Master Plan of Radio Astronomy Development in Indonesia; including the Timau National Observatory ▪Progress Report on VGOS Construction at Bosscha Observatory ▪Towards a more global VLBI network, IVS, AOV, EAVN, etc. 20XX 2 WHERE ARE WE LOCATED? Sumatra Kalimantan Jawa Papua Sulawesi INDONESIA Jakarta Bandung Semarang Surabaya Yogyakarta Malang Banyuwangi ITB Bosscha Observatory In Lembang, 15 km from Bandung ITB Ganesha Campus In Bandung 0 Timau National Observatory In West Timor HISTORICAL BACKGROUND BOSSCHA OBSERVATORY 4 BOSSCHA OBSERVATORY WAS PROVIDED WITH SEVERAL OPTICAL TELESCOPES ONE OF THE FIRST FEW OBSERVATORIES IN THE SOUTHERN HEMISPHERE Established in 1923 by NISV, mainly for astronomical research in the southern hemisphere Basically, an optical observatory; double stars observations was one of its main programs For radio astronomy, there was a plan in 1980s (GERT, Swarup et al., 1984). Not yet realized. MASTER PLAN & CURRENT PROGRESS OF RADIO ASTRONOMY DEVELOPMENT IN INDONESIA ▪Part 1: Telecommunication Antenna Conversion project (since 2019); ITB – Indosat Ooredoo; (Hidayat et al. 2022) ▪Part 2: Plan of the 20m Class Telescope at Timau National Observatory (Master Plan 2016); (Sitompul et al. 2024) ▪Part 3: Antenna Conversion in BRIN – Parepare (2022); (Manik et al. 2022) ▪Part 4: Construction of the VLBI Global Observing System (VGOS) Telescope at Bosscha Observatory (planned in 2022); Cooperation between ITB and SHAO ▪Part 5: In long term, Array of Low Frequency Master Plan of Timau National Observatory, 2015; BRIN 6 PART 4: VLBI GLOBAL OBSERVING SYSTEM (VGOS) IN ITB ▪ITB fully supports the cooperation with Shanghai Astronomical Observatory – Chinese Academy of Sciences (SHAO-CAS) and the realization of VGOS Telescope installation at Bosscha Observatory ▪Agreement of both parties concludes in August 2022 after a long discussion ▪Supporting infra structures such as internet connection using FO, electrical power, and supporting building will be provided accordingly ▪Human resources capable to operate and maintain the telescope must be provided as well ▪The facility will be open for multi-disciplinary researches (astronomy, geodesy, data science, telecommunication, software science, etc.) VLBI = Very Long Baseline Interferometry INTRODUCTION The so-called VLBI Global Observing System (VGOS) is the realization of the next-generation VLBI system (Niell et al., 2006, 2018, Petrachenko et al. 2010): •An accuracy of 1 mm in station position •And 0.1 mm/year in station velocity on global scales •Continuous measurements for time series of station positions and EOP •Posting of initial geodetic results less than 24 hours after observations are complete 7 Yebes Ishioka Wettzell performancerelated goal operationalrelated goal Sheshan, Shanghai VGOS was declared operational in 2020 after a visionary journey that involved designing, prototyping, and demonstrating the feasibility of the new observing system to generate highquality geodetic products (Behrend et al. 2023). Niell et al. (2018) validate several of the expectations set forth for the vision of the next-generation geodetic VLBI system. ORGANIZATIONS: IVS (INTERNATIONAL VLBI SERVICE FOR GEODESY AND ASTROMETRY), AOV (ASIA-OCEANIA VLBI GROUP FOR GEODESY AND ASTROMETRY , ETC 8 https://ivscc.gsfc.nasa.gov/about/vlbi/whatis.html Organizations and Countries Consejo Nacional de Investigaciones Cientificas y Scinicas Argentina Geoscience Australia Australia University of Tasmania Australia CSIRO Australia Vienna University of Technology Austria Centro de Radio Astronomia e Aplicacoes Espaciais Brazil Dominion Radio Astrophysical Observatory Canada Chinese Academy of Sciences China Observatoire de Paris France Observatoire de Bordeaux France Deutsches Geodeisches Forschungsinstitut, TU Munchen Germany Bundesamt fur Kartographie und Geodesie Germany Forschungseinrichtung Satellitengeodesie TU Munchen Germany GeoForschungsZentrum Potsdam Germany Max -Planck-Institut fűr Radioastronomie Germany Istituto di Radioastronomia INAF Italy Agenzia Spaziale Italiana Italy Politecnico di Milano DICA Italy Geospatial Information Authority of Japan Japan National Institute of Information and Communications Technology Japan National Astronomical Observatory of Japan Japan National Institute of Polar Research Japan Auckland University of Technology New Zealand Norwegian Mapping Authority Norway Astronomical Institute of St. -Petersburg University Russia Central (Pulkovo) Astronomical Observatory Russia Institute of Applied Astronomy Russia Sternberg Astronomical Institute Russia Hartebeesthoek Radio Astronomy Observatory South Africa Korea Astronomy and Space Science Institute South Korea National Geographic Information Institute South Korea Instituto Geografico Nacional Spain Chalmers University of Technology Sweden Eidgenossische Technische Hochschule Zurich Switzerland Karadeniz Technical University Turkey Main Astronomical Observatory, National Academy of Sciences Kiev Ukraine Laboratory of Radioastronomy of Crimean Astrophysical Observatory Ukraine NASA Goddard Space Flight Center USA U. S. Naval Observatory USA Jet Propulsion Laboratory USA Lack of Stations in Equatorial Region Indonesia may contribute for equatorial region in eastern hemisphere; Improve the y-coordinate of polar motion SCHUNCK ET AL. (2024) Current status of VGOS station network based on Behrend et al. (2023). Blue circles (●) mark the telescopes in the operational 12-station network. Red diamonds (◆) mark the additional 8 telescopes that are expected to be operational soon, building a 20-station network. Black triangles (▲) depict another 9 additional telescopes, representing a future 29-station VGOS network. 9 16 SUPPORTING BUILDING Control Room Backend Room Grounding System, R < 1  Supporting Building Some Accomodations Backend Room April – October 2025 17 POWER HOUSE UPSUPS UPS Manhole Manhole Genset Main Power, 400 kVA Distributor 18 ANTENNA ASSEMBLY June 2025 19 BIG LIFT – 8 JULY 2025 Representative from SHAO, Sun Mian Director of Bosscha Observatory, Hesti Wulandari 20 GNSS PILLARS GNSS Time Comparison GNSS - CORS GNSS Co-location GNSS Co-location August 2025 21 SURFACE PHOTOGRAPHY Surface Photography to adjust the surface shape September – October 2025 NATIONAL NETWORK Indonesian VLBI Network (Indonesia National Radio Astronomical Observatory) - Proposal 2025 No Name longitude latitude alt (m) Diamet er (m) 1 Station 1: Lembang - Bosscha 107° 37' 03.09318" -6° 49' 29.85316" 1255 13 107.6175259 - 6.824959211 2 Station 2: Timau 123° 56' 50.11" -9° 35' 48.75" 1314 20 123.9472528 - 9.596875 3 Station 3: Jatiluhur JAH -5A 107° 24' 38.26" 6° 31' 18.5'' 139 18.3 107.6106278 - 6.521805556 4 Station 4: Jatiluhur JAH -2A 107° 24' 41.72" -6° 31' 23.19" 139 32 107.4115889 - 6.523108333 5 Station 5: Parepare 119 ° 39' 0.36" -3° 58' 44.18" 22 11 119.6501008 - 3.978938969 Very short base line between JAH-2A and JAH-5A: ~184 m Bosscha Site PRESENTATION TITLE 2/11/20XX 23 NATIONAL NETWORK - INDONESIA Parepare Timau Jatiluhur Lembang ~1380 km ~1840 km ~783 km ~2970 km ~4170 km ~550 km EXTENSION TO SOUTHEAST ASIA To Sheshan (SHAO) ~ 4500 km baseline (km) C (mas) K (mas) Q (mas) CVN - JVN 5100 1.81 0.55 0.28 TNRT - Jatiluhur 2970 3.11 0.95 0.48 TNRT - Timau 4170 2.21 0.67 0.35 SCIENCE CASE (GEODETIC) ▪Indonesia is situated at the convergence of three major tectonic plates—the Eurasian, Indo-Australian, and Pacific plates— meaning that while it is not on the Pacific Plate, the Pacific Plate's boundary interacts with the other plates within the Indonesian archipelago. ▪UT1 – UTC ▪ICRF, ITRF, EOP ▪Crustal motion, etc https://www.britannica.com/place/Ring-of-Fire