[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-detail-213297-en":3,"doc-seo-213297-105":30,"detail-sidebar-cat-0-en-105":91},{"code":4,"msg":5,"data":6},0,"success",{"doc_id":7,"user_id":8,"nickname":9,"user_avatar":10,"doc_module":4,"category_id":11,"category_name":12,"doc_title":13,"doc_description":14,"doc_content":15,"file_id":16,"file_url":17,"file_type":18,"file_size":19,"view_count":4,"is_deleted":4,"is_public":20,"is_downloadable":20,"audit_status":20,"page_count":21,"language":22,"language_code":23,"site_id":24,"html_lang":23,"table_of_contents":25,"faqs":26,"seo_title":27,"seo_description":14,"update_tm":28,"read_time":29},213297,962085570644,"Melati","https://ap-avatar.wpscdn.com/davatar_994ba38a5ba835b3df7d355c54d3ed8d",8,"Research & Report","The Messenger - No. 140 - June 2010","The Messenger No. 140 (June 2010) presents an insider overview of the FORS instruments at ESO’s Very Large Telescope, tracing their evolution from early-1990s origins to long-term science operations. It recounts how FORS1 began on UT1 in April 1999, how FORS2 started on UT2 the following year, and how the two instruments together accumulated two decades of productive observing. The article also describes pre-history, consortium formation, design decisions, commissioning, and key milestones leading to successful integration and retirement of FORS1.","The Messenger  \nNo. 140 – June 2010  \nSummaries of a l l E-ELT instrument concept studies 20 years of FORS operations  \nCRIRES search for exoplanets  \nSupport for Chile earthquake victims  \nTelescopes and Instrumentation  \nTwenty Years of FORS Science Operations on the VLT  \nGero Rupprecht1  \nHermann Böhnhardt2  \nSabine Moehler1  \nPalle Møller1  \nIvo Saviane1  \nBodo Ziegler1  \n1 ESO  \n2 Max-Planck-Institut für Sonnensystemforschung, Katlenburg-Lindau, Germany  \nCelebrating the double jubilee of ten years in operation of FORS1 and FORS2, this article summarises, from an insider’s point of view, the history of the FORS instruments, arguably the most prolific on ESO’s Very Large Telescope. The FORS story began in the early 1990s and FORS1 was the first VLT user instrument to be commissioned. Both FORS instruments have undergone considerable evolution and quickly parted from the original concept of being identical twins. They have both made major contributions to scientific research and have helped shape VLT operations. In 2009, FORS1 was retired, but FORS2 continues, fusing the best of both.  \nThe first of April 1999 marks the day science operations started on the Very Large Telescope (VLT), with Unit Telescope 1 (UT1, Antu) only. Two instruments were installed on Antu: ISAAC, (the Infrared Spectrometer And Array Camera) designed and built by ESO, and FORS1,(the first FOcal Reducer/low dispersion Spectrograph) created by VIC, the VLT Instrument Consortium, composed of the observatories of Heidelberg, Göttingen and Munich (Germany) . Exactly one year later, FORS2 took up duty on Paranal on UT2 Kueyen. Since then the FORS twins (Figure 1) have provided astronomers with a wealth of observational data of excellent quality. The successful teamwork of the two FORS instruments came to an end on 1 April 2009 with the retirement of FORS1 after exactly ten years of operations. FORS2 reached the ten-year mark one year later, so on 1 April of this year, the two FORS instruments together had racked up a total of 20 years of successful science operations.  \nFigure 1. The FORStwins, in separate UTs.  \nSome pre-history  \nThe origins of what became FORS date back a long way. The report of the Working Group on Imaging and Low Resolution Spectroscopy (VLT Report No. 52) in July 1986 recommended building “a set of general purpose focal reducers at one Nasmyth focus on each of the (four) array elements” (that is, the UTs) . The only direct legacy of this far-reaching recommendation are the twin FORS instruments. In June 1989 ESO issued the VLT Instrumentation Plan asking for comments and expressions of interest from European institutes. In response to the ESO call, a consortium was formed by Immo Appenzeller of the Landessternwarte in Heidelberg as Principal Investigator, with Rolf Kudritzki of the University of Munich and Klaus Fricke of the University of Göttingen as co-Investigators.  \nThis consortium intended to submit a proposal for the medium-high resolution spectrograph, now known as UVES.  \nESO, however, finally decided to build this instrument internally, so the consortium changed course at short notice and entered the competitive tender with a bid for the focal reducer/low dispersion spectrograph instead! The bid was successful, against one competing proposal, and after lengthy contract negotiations involving the project institutes, their host universities and, by the end, three different German federal states as well as several federal ministries, the contract with ESO was signed in December 1991. The contract foresaw ESO paying for the FORS  \nhardware and the provision of the detector systems; in addition the consortium invested substantially in its infrastructure in support of the FORS project and about 130-person years of work until the completion of the project. At the final acceptance of the FORS instruments by ESO, the FORS consortium even stayed under budget. In return for its effort, the consortium was granted 66 nights of guarante","cbCaifVtsGn4mil7","https://ap.wps.com/l/cbCaifVtsGn4mil7","pdf",14535174,1,68,"English","en",105,"# Twenty Years of FORS Science Operations on the VLT\n## Commissioning\n## Some pre-history","[{\"question\":\"What do FORS1 and FORS2 contribute to VLT science operations?\",\"answer\":\"They provided astronomers with high-quality observational data and shaped VLT operations, making major contributions to scientific research.\"},{\"question\":\"When did science operations begin for FORS on the VLT?\",\"answer\":\"Science operations started on 1 April 1999 with FORS1 on UT1, with FORS2 taking up duty one year later on UT2.\"},{\"question\":\"What historical factors led to the creation of the FORS instruments?\",\"answer\":\"A 1986 recommendation for general-purpose focal reducers, followed by an ESO instrumentation plan and a consortium formed in 1989, eventually resulted in building the focal reducer/low dispersion spectrograph with contracts signed in December 1991.\"}]","The Messenger - No. 140 - June 2010 | PDF",1788757073,171,{"code":4,"msg":31,"data":32},"ok",{"site_id":24,"language":23,"slug":33,"title":13,"keywords":34,"description":14,"schema_data":35,"social_meta":86,"head_meta":88,"extra_data":90,"updated_unix":28},"the-messenger-no-140-june-2010","",{"@graph":36,"@context":85},[37,54,68],{"@type":38,"itemListElement":39},"BreadcrumbList",[40,44,48,51],{"item":41,"name":42,"@type":43,"position":20},"https://docshare.wps.com","Home","ListItem",{"item":45,"name":46,"@type":43,"position":47},"https://docshare.wps.com/document/","Document",2,{"item":49,"name":12,"@type":43,"position":50},"https://docshare.wps.com/document/research-report/",3,{"item":52,"name":13,"@type":43,"position":53},"https://docshare.wps.com/document/the-messenger-no-140-june-2010/213297/",4,{"url":52,"name":13,"@type":55,"author":56,"headline":13,"publisher":58,"fileFormat":61,"inLanguage":23,"description":14,"dateModified":62,"datePublished":62,"encodingFormat":61,"isAccessibleForFree":63,"interactionStatistic":64},"DigitalDocument",{"name":9,"@type":57},"Person",{"url":41,"name":59,"@type":60},"DocShare","Organization","application/pdf","2026-09-07",true,{"@type":65,"interactionType":66,"userInteractionCount":4},"InteractionCounter",{"@type":67},"ViewAction",{"@type":69,"mainEntity":70},"FAQPage",[71,77,81],{"name":72,"@type":73,"acceptedAnswer":74},"What do FORS1 and FORS2 contribute to VLT science operations?","Question",{"text":75,"@type":76},"They provided astronomers with high-quality observational data and shaped VLT operations, making major contributions to scientific research.","Answer",{"name":78,"@type":73,"acceptedAnswer":79},"When did science operations begin for FORS on the VLT?",{"text":80,"@type":76},"Science operations started on 1 April 1999 with FORS1 on UT1, with FORS2 taking up duty one year later on UT2.",{"name":82,"@type":73,"acceptedAnswer":83},"What historical factors led to the creation of the FORS instruments?",{"text":84,"@type":76},"A 1986 recommendation for general-purpose focal reducers, followed by an ESO instrumentation plan and a consortium formed in 1989, eventually resulted in building the focal reducer/low dispersion spectrograph with contracts signed in December 1991.","https://schema.org",{"og:url":52,"og:type":87,"og:title":13,"og:site_name":59,"og:description":14},"article",{"robots":89,"canonical":52},"index,follow",{"doc_id":7,"site_id":24},{"code":4,"msg":5,"data":92},[93,97,101,105,110,115,120,123,128,131,135],{"id":20,"doc_module":4,"doc_module_name":46,"category_name":94,"show_sort_weight":95,"slug":96},"Story & Novel",90,"story-novel",{"id":47,"doc_module":4,"doc_module_name":46,"category_name":98,"show_sort_weight":99,"slug":100},"Literature",80,"literature",{"id":53,"doc_module":4,"doc_module_name":46,"category_name":102,"show_sort_weight":103,"slug":104},"Exam",70,"exam",{"id":106,"doc_module":4,"doc_module_name":46,"category_name":107,"show_sort_weight":108,"slug":109},5,"Comic",60,"comic",{"id":111,"doc_module":4,"doc_module_name":46,"category_name":112,"show_sort_weight":113,"slug":114},6,"Technology",50,"technology",{"id":116,"doc_module":4,"doc_module_name":46,"category_name":117,"show_sort_weight":118,"slug":119},7,"Healthcare",40,"healthcare",{"id":11,"doc_module":4,"doc_module_name":46,"category_name":12,"show_sort_weight":121,"slug":122},30,"research-report",{"id":124,"doc_module":4,"doc_module_name":46,"category_name":125,"show_sort_weight":126,"slug":127},9,"Religion & Spirituality",20,"religion-spirituality",{"id":126,"doc_module":4,"doc_module_name":46,"category_name":129,"show_sort_weight":126,"slug":130},"World Cup","world-cup",{"id":132,"doc_module":4,"doc_module_name":46,"category_name":133,"show_sort_weight":132,"slug":134},10,"Lifestyle","lifestyle",{"id":136,"doc_module":4,"doc_module_name":46,"category_name":137,"show_sort_weight":106,"slug":138},19,"General","general"]