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73-573: As of October 1, 2014, funding ceased for the National Virtual Observatory (NVO) and all code and digital assets of the project were made publicly available at the VAO Closeout Repository. The NVO was conceived to allow scientists to grapple with the enormous growth in astronomical data resulting from significant advances in telescope , detector , and computer technologies. These advances have resulted in

146-412: A basic calibration that spans the lifetime of each instrument. The calibration program includes measurements that are made relative to on-board calibration sources or to assess internal detector noise levels as well as observations of astronomical standard stars and fields, needed to determine absolute flux conversions and astrometric transformations. The external calibrations on HST typically total 5-10% of

219-534: A broad range of astrophysics including investigations of the Solar System , exoplanet detection and characterization, star formation , galaxy evolution, and physical cosmology . STScI hosts an annual scientific symposium held each spring as well as several smaller scientific workshops. The employment of an active scientific staff at STScI helps to ensure that HST, and eventually JWST, perform at peak capability. STScI's Office of Public Outreach (OPO) provides

292-544: A few bands can be observed from the Earth's surface. These bands are visible – near-infrared and a portion of the radio-wave part of the spectrum. For this reason there are no X-ray or far-infrared ground-based telescopes as these have to be observed from orbit. Even if a wavelength is observable from the ground, it might still be advantageous to place a telescope on a satellite due to issues such as clouds, astronomical seeing and light pollution . The disadvantages of launching

365-504: A focal point. Optical telescopes are used for astronomy and in many non-astronomical instruments, including: theodolites (including transits ), spotting scopes , monoculars , binoculars , camera lenses , and spyglasses . There are three main optical types: A Fresnel imager is a proposed ultra-lightweight design for a space telescope that uses a Fresnel lens to focus light. Beyond these basic optical types there are many sub-types of varying optical design classified by

438-656: A great deal of follow-up work (see, for example, http://www.stsci.edu/ftp/science/hdf/clearinghouse/clearinghouse.html and http://www.stsci.edu/hst/udf/index_html ). STScI is responsible for developing, enhancing, and maintaining most of the ground systems used to carry out our Hubble science operations described above. These systems originally (1980s, early 1990s) came from several sources, including in-house STScI developments and work done under NASA contracts with various vendors. Over HST's lifetime substantial work has been done on these systems - even while they were supporting daily operations of Hubble. They have been integrated into

511-419: A mirror instead of a lens was being investigated soon after the invention of the refracting telescope. The potential advantages of using parabolic mirrors —reduction of spherical aberration and no chromatic aberration —led to many proposed designs and several attempts to build reflecting telescopes . In 1668, Isaac Newton built the first practical reflecting telescope, of a design which now bears his name,

584-431: A more effective and easier to operate end-to-end system. They have been through major technology upgrades (e.g., improved operating systems and computer hardware, higher capacity archive storage media). They have also been modified to support the succession of instruments installed in the telescope. In the last several years, they have been modified to support WFC3 and COS, the two new instruments that will be installed during

657-421: A more integrated and user-friendly archive. It will provide raw Hubble data as well as higher-level science products (color images, mosaics, etc.). STScI is responsible for in-flight calibration of the science instruments on HST and JWST. For HST, a calibration plan for the observatory is developed each year. This plan is designed to support the selected GO observation programs for that cycle, as well as to provide

730-630: A plethora of images, other data, and catalogs. In August 2001, the NSF allocated funding for a proposal entitled "Framework for the National Virtual Observatory ". The grant was approved under its Information Technology Research program (since superseded). NVO funding supported collaboration to produce a distributed computing framework for an integrated cyber infrastructure for astronomers providing seamless access to these astronomical resources. The manifestation of this infrastructure

803-475: A single receiver and records a single time-varying signal characteristic of the observed region; this signal may be sampled at various frequencies. In some newer radio telescope designs, a single dish contains an array of several receivers; this is known as a focal-plane array . By collecting and correlating signals simultaneously received by several dishes, high-resolution images can be computed. Such multi-dish arrays are known as astronomical interferometers and

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876-625: A space telescope include cost, size, maintainability and upgradability. Some examples of space telescopes from NASA are the Hubble Space Telescope that detects visible light, ultraviolet, and near-infrared wavelengths, the Spitzer Space Telescope that detects infrared radiation, and the Kepler Space Telescope that discovered thousands of exoplanets. The latest telescope that was launched was

949-477: A telescope was a 1608 patent submitted to the government in the Netherlands by Middelburg spectacle maker Hans Lipperhey for a refracting telescope . The actual inventor is unknown but word of it spread through Europe. Galileo heard about it and, in 1609, built his own version, and made his telescopic observations of celestial objects. The idea that the objective , or light-gathering element, could be

1022-515: A variety of astronomy-related products and features for use by the general public and informal education venues including museums, science centers, planetariums, and libraries. These include background articles, telescope imagery, illustrations, diagrams, infographics, videos, scientific visualizations, virtual reality, and interactives. Most of these resources are distributed via websites developed and managed by STScI, including Hubblesite , Webbtelescope , ViewSpace , and Illuminated Universe . Content

1095-827: A wide array of products and services designed to share and communicate the science and discoveries of HST, JWST, Roman, and astronomy in general with the general public. OPO's efforts focus on meeting the needs of the media, the informal science education community, and the general public. OPO produces approximately 40 new press releases each year featuring HST discoveries and science results. These media packages include news stories, Hubble images, explanatory artwork, animations, and supplementary information for use by print, broadcast, and online media. OPO also participates in press conferences for particularly newsworthy discoveries, and conducts science writers' workshops for in-depth sessions with scientists working on current astrophysical research problems. In addition to news releases, OPO develops

1168-580: Is a device used to observe distant objects by their emission, absorption , or reflection of electromagnetic radiation . Originally, it was an optical instrument using lenses , curved mirrors , or a combination of both to observe distant objects – an optical telescope . Nowadays, the word "telescope" is defined as a wide range of instruments capable of detecting different regions of the electromagnetic spectrum , and in some cases other types of detectors. The first known practical telescopes were refracting telescopes with glass lenses and were invented in

1241-479: Is also distributed via social media platforms, including Facebook, Twitter, Instagram, and YouTube. OPO also conducts outreach via live events in person and online. These include a regular Public Lecture Series as well as attendance at various local and national STEM events. OPO also provides support to informal education venues in the form of print materials, program/event resources, and professional development. OPO's outreach efforts are conducted in partnership with

1314-781: Is broadly related to the scientific mission of the Hubble Space Telescope. In 2009, it was combined with the Spitzer Fellowship that since 2002 had been associated with the Spitzer Space Telescope and science program. It now supports fellows undertaking research associated with all missions within the Cosmic Origins theme: the Herschel Space Observatory , Hubble Space Telescope (HST), James Webb Space Telescope (JWST), Stratospheric Observatory for Infrared Astronomy (SOFIA), and

1387-412: Is called an observatory . Radio telescopes are directional radio antennas that typically employ a large dish to collect radio waves. The dishes are sometimes constructed of a conductive wire mesh whose openings are smaller than the wavelength being observed. Unlike an optical telescope, which produces a magnified image of the patch of sky being observed, a traditional radio telescope dish contains

1460-528: Is now also being applied to optical telescopes using optical interferometers (arrays of optical telescopes) and aperture masking interferometry at single reflecting telescopes. Radio telescopes are also used to collect microwave radiation , which has the advantage of being able to pass through the atmosphere and interstellar gas and dust clouds. Some radio telescopes such as the Allen Telescope Array are used by programs such as SETI and

1533-482: Is possible to make very tiny antenna). The near-infrared can be collected much like visible light; however, in the far-infrared and submillimetre range, telescopes can operate more like a radio telescope. For example, the James Clerk Maxwell Telescope observes from wavelengths from 3 μm (0.003 mm) to 2000 μm (2 mm), but uses a parabolic aluminum antenna. On the other hand,

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1606-449: Is provided to STScI on what is called a Phase II proposal. The Phase II proposal specifies instrument operation modes, exposure times, telescope orientations, and so on. The STScI staff provide the web-based software called Exposure Time Calculators (ETCs) that allow GOs to estimate how much observing time any of the onboard detectors will need to accumulate the amount of light required to accomplish their scientific objectives. In addition,

1679-796: Is the science operations center for the Hubble Space Telescope (HST), science operations and mission operations center for the James Webb Space Telescope (JWST), and science operations center for the Nancy Grace Roman Space Telescope . STScI was established in 1981 as a community-based science center that is operated for NASA by the Association of Universities for Research in Astronomy (AURA). STScI's offices are located on

1752-406: Is underway on several 30–40m designs. The 20th century also saw the development of telescopes that worked in a wide range of wavelengths from radio to gamma-rays . The first purpose-built radio telescope went into operation in 1937. Since then, a large variety of complex astronomical instruments have been developed. Since the atmosphere is opaque for most of the electromagnetic spectrum, only

1825-530: The 2 Micron All Sky Survey (2MASS). Also found in the NVO are NASA 's rich data collections including data from the Hubble Space Telescope , the Chandra X-ray Observatory , the Spitzer Space Telescope , and other space -based missions. The NVO Closeout Repository provides access to a variety of additional data from nearly every astronomical research facility, observatory, and telescope across

1898-645: The Arecibo Observatory to search for extraterrestrial life. An optical telescope gathers and focuses light mainly from the visible part of the electromagnetic spectrum. Optical telescopes increase the apparent angular size of distant objects as well as their apparent brightness . For the image to be observed, photographed, studied, and sent to a computer, telescopes work by employing one or more curved optical elements, usually made from glass lenses and/or mirrors , to gather light and other electromagnetic radiation to bring that light or radiation to

1971-822: The Earth's atmosphere is opaque to this part of the electromagnetic spectrum. An example of this type of telescope is the Fermi Gamma-ray Space Telescope which was launched in June 2008. The detection of very high energy gamma rays, with shorter wavelength and higher frequency than regular gamma rays, requires further specialization. Such detections can be made either with the Imaging Atmospheric Cherenkov Telescopes (IACTs) or with Water Cherenkov Detectors (WCDs). Examples of IACTs are H.E.S.S. and VERITAS with

2044-989: The International Ultraviolet Explorer (IUE), the Extreme Ultraviolet Explorer (EUVE), the Far Ultraviolet Spectroscopic Explorer (FUSE), and the Galaxy Evolution Explorer (GALEX). Kepler and JWST science data will be archived and retrieved in similar fashions. The internet serves as the primary user interface to the data archives at STScI ( http://archive.stsci.edu ). The archive currently holds over 30 terabytes of data. Each day about 11 gigabytes of new data are ingested and about 85 gigabytes of data are distributed to users. The Hubble Legacy Archive (HLA; http://hla.stsci.edu/ ), currently in development, will act as

2117-722: The Johns Hopkins University Homewood Campus and in the Rotunda building in Baltimore , Maryland . In addition to performing continuing science operations of HST and preparing for scientific exploration with JWST and Roman, STScI manages and operates the Mikulski Archive for Space Telescopes (MAST), which holds data from numerous active and legacy missions, including HST, JWST, Kepler , TESS , Gaia , and Pan-STARRS . Most of

2190-562: The National Optical Astronomy Observatories ). STScI provides all technical and logistical support for these activities. The annual cycle of proposal calls was occasionally altered in duration in years when a HST servicing mission was scheduled. Proposers fortunate enough to be awarded telescope time, referred to as General Observers (GOs), must then provide detailed requirements needed to schedule and implement their observing programs. This information

2263-405: The Netherlands at the beginning of the 17th century. They were used for both terrestrial applications and astronomy . The reflecting telescope , which uses mirrors to collect and focus light, was invented within a few decades of the first refracting telescope. In the 20th century, many new types of telescopes were invented, including radio telescopes in the 1930s and infrared telescopes in

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2336-504: The Newtonian reflector . The invention of the achromatic lens in 1733 partially corrected color aberrations present in the simple lens and enabled the construction of shorter, more functional refracting telescopes. Reflecting telescopes, though not limited by the color problems seen in refractors, were hampered by the use of fast tarnishing speculum metal mirrors employed during the 18th and early 19th century—a problem alleviated by

2409-423: The Spitzer Space Telescope , observing from about 3 μm (0.003 mm) to 180 μm (0.18 mm) uses a mirror (reflecting optics). Also using reflecting optics, the Hubble Space Telescope with Wide Field Camera 3 can observe in the frequency range from about 0.2 μm (0.0002 mm) to 1.7 μm (0.0017 mm) (from ultra-violet to infrared light). With photons of the shorter wavelengths, with

2482-607: The University of Wisconsin–Madison , and National Radio Astronomy Observatory . The NVO, a US effort, had affiliates throughout the international astronomical community including IVOA , AstroGrid (UK), Euro-VO , the Japanese VO, the Australian VO, VO India and ten other national programs. Along with its objective to serve the scientific community by enabling research through distributed data sources and services,

2555-764: The 1960s. The word telescope was coined in 1611 by the Greek mathematician Giovanni Demisiani for one of Galileo Galilei 's instruments presented at a banquet at the Accademia dei Lincei . In the Starry Messenger , Galileo had used the Latin term perspicillum . The root of the word is from the Ancient Greek τῆλε, romanized tele 'far' and σκοπεῖν, skopein 'to look or see'; τηλεσκόπος, teleskopos 'far-seeing'. The earliest existing record of

2628-423: The 4 planned for JWST are summarized in the table below. HST instruments can detect light with wavelengths from the ultraviolet through the near infrared . JWST instruments will operate from the red-end of optical wavelengths (~6000 Angstroms) to the mid-infrared (5 to 27 micrometres). Instruments listed as decommissioned are no longer on board. STScI staff develops the calibration proposals, shepherd them through

2701-693: The GO observing program, with more time required when an instrument is still relatively new. HST has had a total of 12 science instruments to date, 6 of which are currently active. Two new instruments were installed during the May 2009 HST servicing mission STS-125 . Electronic failures in STIS (in 2001) and in the ACS Wide-Field Channel (in 2007) were also repaired on-orbit in May 2009, bringing these instruments back to active status. All 12 HST instruments plus

2774-573: The HST and JWST project. The total STScI staff consists of about 850 people as of 2021. STScI operates its missions on behalf of NASA, the worldwide astronomy community, and to the benefit of the public. The science operations activities directly serve the astronomy community, primarily in the form of HST and JWST (and eventually Roman) observations and grants, but also include distributing data from other NASA and ground-based missions via MAST. The ground system development activities create and maintain

2847-440: The Hubble Space Telescope. The first step in this process is to support the annual community-led selection of the scientific programs that will be performed with HST. This begins with publishing of the annual Call for Proposals, which specifies the currently supported science instrument capabilities, proposal requirements and the submission deadline. Anyone is eligible to submit a proposal. All proposals are critically peer-reviewed by

2920-627: The James Webb Space Telescope on December 25, 2021, in Kourou, French Guiana. The Webb telescope detects infrared light. The name "telescope" covers a wide range of instruments. Most detect electromagnetic radiation , but there are major differences in how astronomers must go about collecting light (electromagnetic radiation) in different frequency bands. As wavelengths become longer, it becomes easier to use antenna technology to interact with electromagnetic radiation (although it

2993-574: The NVO began with combined funding from NSF and NASA and programmatically executed through NSF. Scientists originally accessed the NVO through the NVO website. Data in the NVO Closeout Repository are available from a variety of observatories and wavelengths , including NSF 's National Optical Astronomy Observatory (NOAO), National Radio Astronomy Observatory (NRAO), the Sloan Digital Sky Survey (SDSS), and

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3066-518: The NVO served the public through educational and outreach resources on the Virtual Observatory website. The modest NVO Education and Public Outreach (EPO) effort was coordinated from Space Telescope Science Institute . The NVO provided technical support for the development of educational modules integrated into partner programs. NVO EPO coordinated activities with the international communities as well. Telescope A telescope

3139-457: The Phase II information is gathered, a long-range observing plan is developed that covers the entire year, finding appropriate times to schedule individual observations, and at the same time ensuring effective and efficient use of the telescope through the year. Detailed observing schedules are created each week, including, in the case of HST operations, scheduling the data communication paths via

3212-451: The STScI staff carries out all the steps necessary to implement each specific program, as well as plan the entire ensemble of programs for the year. For HST, this includes finding guide stars, checking on bright object constraints, implementing specific scheduling requirements, and working with observers to understand and factor in specific or any non-standard requirements they may have. Once

3285-457: The STScI will be responsible for using the wavefront sensor system developed by JPL and Northrop Grumman Space Technology (NGST, the NASA contractor building the observatory) to monitor and adjust the segmented telescope. The post observation support includes a HelpDesk that users can contact to answer their questions about any aspect of observing – from how to submit a proposal to how to analyze

3358-527: The Spitzer Space Telescope. The research may be theoretical, observational, or instrumental. Each year, since HST's launch in 1990, 8 to 12 fellowships are awarded; from 2009 it hovers about 16. STScI also sponsors a summer student intern program that allows talented undergraduate students from around the world to work with the institute's scientific staff, providing these students with hands-on experience in state-of-the-art astronomical research. STScI's full-time scientific staff conducts original research spanning

3431-688: The Time Allocation Committee (TAC). The TAC consists of about 100 members of the U.S. and international astronomical community, selected to represent a broad range of research expertise needed to evaluate the proposals. Each proposal cycle typically involves reviewing 700 to 1100 proposals. Only 15 - 20% of these proposals will eventually be selected for implementation. The TAC reviews several categories of observing time, as well as proposals for archival, theoretical, and combined research projects between HST and other space-based or ground-based observatories (e.g., Chandra X-ray Observatory and

3504-541: The Tracking and Data Relay Satellite System ( TDRSS ) and generating the binary command loads for uplink to the spacecraft. Adjustments can be made to both long-range and weekly plans in response to Targets of Opportunity (e.g., for transient events like supernovae or coordination with one-of-a-kind events such as comet impact spacecraft). The STScI uses the Min-conflicts algorithm to schedule observation time on

3577-466: The brightness of the source). They include global effects, such as charge transfer efficiency in the charge-coupled devices , as well as effects specific to modes and filters, such as filter "ghosts" (caused by subtle scattering of light within an instrument). Awareness of these effects can come from STScI staff as they analyze calibration programs, or from observers who find oddities in their data and provide feedback to STScI. The STScI staff also performs

3650-405: The characterization and calibration of the telescope itself. In the case of HST, this has evolved to primarily be a matter of monitoring and adjusting focus, and monitoring and measuring point spread functions . (In the early 1990s, the STScI was responsible for accurate measurement of the spherical aberration , necessary for the corrective optics of all subsequent instruments). In the case of JWST,

3723-399: The data become available to anyone who wishes to access it. Data sets retrieved from the archive are automatically re-calibrated to ensure that the most up-to-date calibration factors and software are applied. The STScI serves as the archive center for all of NASA's optical/UV space missions. In addition to archiving and storing HST science data, STScI holds data from 13 other missions including

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3796-413: The data by removing instrumental artifacts. The calibration steps are different for each HST instrument, but as a general rule they include cosmic ray removal, correction for instrument/detector non-uniformities, flux calibration, and application of world coordinate system information (which tells the user precisely where on the sky the detector was pointed). The calibrations applied are the best available at

3869-714: The data. The STScI performs large HST science programs on behalf of the community. These are programs with broad scientific applications. To date, these programs include the Hubble Deep Field (HDF), the Hubble Deep Field South (HDFS), and the Ultra Deep Field (UDF). The raw and processed data for these observations are made available to the astronomy community nearly immediately. These products have then been used by many astronomers in pursuit of their own research topics, and have motivated

3942-484: The form of published papers. Results are also incorporated into the Data Handbooks and Instrument Handbooks. In addition to calibration of the instruments, STScI staff characterizes and documents the performance of the instrument, so users can better understand how to interpret their data. These are generally effects that are not automatically corrected for in the pipeline (because they vary with time or depend on

4015-676: The funding for STScI activities comes from contracts with NASA's Goddard Space Flight Center but there are smaller activities funded by NASA's Ames Research Center , NASA's Jet Propulsion Laboratory , and the European Space Agency (ESA). The staff at STScI consists of scientists (mostly astronomers and astrophysicists), spacecraft engineers, software engineers, data management personnel, education and public outreach experts, and administrative and business support personnel. There are approximately 200 Ph.D. scientists working at STScI, 15 of whom are ESA staff who are on assignment to

4088-808: The globe. The NVO development project was distributed across many institutions and includes teams at the Johns Hopkins University , California Institute of Technology , Space Telescope Science Institute , NOAO , Infrared Processing and Analysis Center , San Diego Supercomputer Center , and the Associated Universities, Inc . Affiliate organizations with participating teams include Goddard Space Flight Center , Carnegie Mellon University , University of Pittsburgh , National Center for Supercomputing Applications , Smithsonian Astrophysical Observatory , University of Southern California , Fermilab , United States Naval Observatory ,

4161-682: The higher frequencies, glancing-incident optics, rather than fully reflecting optics are used. Telescopes such as TRACE and SOHO use special mirrors to reflect extreme ultraviolet , producing higher resolution and brighter images than are otherwise possible. A larger aperture does not just mean that more light is collected, it also enables a finer angular resolution. Telescopes may also be classified by location: ground telescope, space telescope , or flying telescope . They may also be classified by whether they are operated by professional astronomers or amateur astronomers . A vehicle or permanent campus containing one or more telescopes or other instruments

4234-415: The introduction of silver coated glass mirrors in 1857, and aluminized mirrors in 1932. The maximum physical size limit for refracting telescopes is about 1 meter (39 inches), dictating that the vast majority of large optical researching telescopes built since the turn of the 20th century have been reflectors. The largest reflecting telescopes currently have objectives larger than 10 meters (33 feet), and work

4307-522: The next HST servicing mission, and to support the 2- Gyroscope mode of HST operations. STScI also provides subsets of ground system services to other astronomy missions, including FUSE, Kepler, and JWST. STScI's software engineers maintain about 7,900,000 source lines of code . STScI routinely participates with NASA and industry system engineers and scientists in developing the overall mission architecture. For HST, this includes helping to determine and prioritize servicing mission activities and development of

4380-614: The next-generation gamma-ray telescope, the Cherenkov Telescope Array ( CTA ), currently under construction. HAWC and LHAASO are examples of gamma-ray detectors based on the Water Cherenkov Detectors. A discovery in 2012 may allow focusing gamma-ray telescopes. At photon energies greater than 700 keV, the index of refraction starts to increase again. Space Telescope Science Institute The Space Telescope Science Institute ( STScI )

4453-647: The observatory. Real-time operations are staffed around the clock. Flight operations activities for HST are done at NASA's GSFC in Greenbelt, Maryland. Science data from HST arrive at the STScI a few hours after being downlinked from TDRSS and subsequently passing through a data capture facility at NASA's Goddard Space Flight Center. Once at STScI, the data are processed by a series of computer algorithms that convert its format into an internationally accepted standard (known as FITS : Flexible Image Transport System ), correct for missing data, and perform final calibration of

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4526-494: The professional astronomy community through a number of channels, including participation at the bi-annual meetings of the American Astronomical Society , publication of regular STScI newsletters and the STScI website, hosting user committees and science working groups, and holding several scientific and technical symposia and workshops each year. These activities enable STScI to disseminate information to

4599-546: The rays just a few degrees . The mirrors are usually a section of a rotated parabola and a hyperbola , or ellipse . In 1952, Hans Wolter outlined 3 ways a telescope could be built using only this kind of mirror. Examples of space observatories using this type of telescope are the Einstein Observatory , ROSAT , and the Chandra X-ray Observatory . In 2012 the NuSTAR X-ray Telescope

4672-434: The scheduling process, and analyze the data they produce. These programs provide updated calibration and reference files to be used in the data processing pipeline. The calibration files are also archived so users can retrieve them if they need to manually recalibrate their data. All calibration activity and results are documented, usually in the form of Instrument Science Reports posted to the public website, and occasionally in

4745-556: The servicing strategy. For JWST, this includes participating in the definition of high-level science requirements and the overall architecture for the mission. In both cases, the STScI focuses on the scientific capabilities of the mission, and also the requirements for smooth and efficient operations of the observatory. STScI manages the selection of the Hubble Fellowship Program . Since 1990, Hubble Fellowships support outstanding postdoctoral scientists whose research

4818-420: The software systems that are needed to provide these services to the astronomy community. STScI's public outreach activities provide a wide range of resources for media, informal education venues such as planetariums and science museums, and the general public. STScI also serves as a source of guidance to NASA on a range of optical and UV space astrophysics issues. The STScI staff interacts and communicates with

4891-511: The task they perform such as astrographs , comet seekers and solar telescopes . Most ultraviolet light is absorbed by the Earth's atmosphere, so observations at these wavelengths must be performed from the upper atmosphere or from space. X-rays are much harder to collect and focus than electromagnetic radiation of longer wavelengths. X-ray telescopes can use X-ray optics , such as Wolter telescopes composed of ring-shaped 'glancing' mirrors made of heavy metals that are able to reflect

4964-519: The technique is called aperture synthesis . The 'virtual' apertures of these arrays are similar in size to the distance between the telescopes. As of 2005, the record array size is many times the diameter of the Earth – using space-based very-long-baseline interferometry (VLBI) telescopes such as the Japanese HALCA (Highly Advanced Laboratory for Communications and Astronomy) VSOP (VLBI Space Observatory Program) satellite. Aperture synthesis

5037-408: The telescope user community as well as enabling the STScI staff to maximize the scientific productivity of the facilities they operate by responding to the needs of the community and of NASA. Note: Information in this section needs updating. For current activities, consult STScI's official website. The STScI conducts all activities required to select, schedule, and implement the science programs of

5110-667: The telescope. The STScI is currently developing similar processes for JWST, although the operational details will be very different due to its different instrumentation and spacecraft constraints, and its location at the Sun-Earth L2 Lagrange point (~1.5 million km from Earth) rather than the low Earth orbit (~565 km) used by HST. Flight Operations consists of the direct support and monitoring of HST functions in real-time. Real-time daily flight operations for HST include about 4 command load uplinks, about 10 data downlinks, and near continuous health and safety monitoring of

5183-450: The time the data passes through the pipeline. The STScI is working with instrument developers to define similar processes for Kepler and JWST data. All HST science data are permanently archived after passing through the calibration pipeline. NASA policy mandates a one-year proprietary period on all data, which means that only the initial proposal team can access the data for the first year after it has been obtained. Subsequent to that year,

5256-400: Was an operational “virtual observatory” available to scientists and to the public. Investigators acquired existing astronomical data from a variety of observatory archives through “virtual instruments”, that is, computer interfaces, tools, and services. The NVO was planned and implemented in synergy with the research community, the primary users of the system. In 2007, the operational stage of

5329-447: Was launched which uses Wolter telescope design optics at the end of a long deployable mast to enable photon energies of 79 keV. Higher energy X-ray and gamma ray telescopes refrain from focusing completely and use coded aperture masks: the patterns of the shadow the mask creates can be reconstructed to form an image. X-ray and Gamma-ray telescopes are usually installed on high-flying balloons or Earth-orbiting satellites since

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