Note: the Ag curve describes reflection, not transmission for the pickoff mirror. A time-tested mount, proven strong by years of dedicated service and refinement, the Losmandy GM-8 doesn't know how to disappoint anymore- only how to perform. These over-clocked shift speeds come at the cost of reduced single pixel well depth. They were built to primarily perform speckle interferometry providing diffraction-limited imagery at optical wavebands, yielding pixel scale uncertainties of 0.21 mas, position angle uncertainties of 0.7, and photometric uncertainties of m 0.020.04 magnitudes (for the blue and red channels, respectively) when run through the standard data reduction pipeline. Astronomical J. Usually within a few weeks, speckle data are run through our data reduction pipeline which produces reconstructed speckle images and 5 contrast detection limit curves for each target in both filters. Astronauts had to learn how to walk in space. The Gemini Observatory's international headquarters is located in Hilo,Hawaii at the University of Hawaii Hilo's University Park. Corrections? Some of these interesting and atypical use cases currently being investigated include: large samples of nearby M/K/brown dwarfs, creating an unbiased TESS sample, cluster photometer and astrometry, transit photometry and occultation, and Nova shells or possible stellar mergers Figure 9. DC provided suggestions, DM wrote the instrument software used for the data provided, and EQ advised on the fabrication of the instrument. All raw data are also uploaded to the Gemini Observatory Archive.3 The data are subject to a proprietary period as specified by the principal investigator of the program. Stars with no bars were only observed once and we assign no formal errors to the V magnitudes taken from the WDS. (2021b). At any given time each telescope has 4 instruments mounted at the Cassegrain focus (including Alopeke at Gemini North and Zorro at Gemini South) and the tertiary mirror can quickly direct the light to the requested instrument. One key aspect of the instruments is the simultaneous operation of two optical channels. 141, 180. doi:10.1088/0004-6256/141/6/180, Horch, E. P., Howell, S. B., Everett, M. E., and Ciardi, D. R. (2014). Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher. (2010). Following the construction and installation of the NASA-NSF Exoplanet Observational Research (NN-EXPLORE) Exoplanet Stellar Speckle Imager (NESSI) at the WIYN telescope (Scott et al., 2018), our research group built two additional speckle imagers for the twin Gemini-North and Gemini-South telescopes located in Hawaii and Chile, respectively. Higher uncertainties can occur for large values of m, seeing greater than about 0.8 arcsec, and times seeing values greater than 0.6 arcsec2. Figure 8 illustrates the effect of blended binaries when observed with different instruments; only high-resolution imaging can resolve sub-arcsecond binaries. Nifty50 home | 50th anniversary | NSF history | NSF home, Proposal & Award Policies & Procedures Guide (PAPPG), National Center for Science & Engineering Statistics (NCSES), Budget, Performance & Financial Reporting. For wide field mode the input optics are two two in diameter lenses with focal lengths of 75 mm and -100 mm and the camera lenses have a 50 mm focal length. 158, 48. doi:10.3847/1538-3881/ab24e4, Winters, J. G., Henry, T. J., Jao, W.-C., Subasavage, J. P., Chatelain, J. P., Slatten, K., et al. The standard deviation of the difference between frame timestamp and calculated frame time (from first frame + KCT*frame_number) is 19.5ns For future time-domain work the incorporation of individual GPS time receivers to externally trigger the cameras should enable 10ns precision. By comparing the precisely known position of the GPS satellite for a given time from the empherides and comparing it with our observations (Figure 11) the accuracy of our camera time stamps can be measured directly. Gemini Observatory, observatory consisting of two 8.1-metre (27-foot) telescopes: the Frederick C. Gillett Gemini Telescope (also called Gemini North), located on the dormant volcano Mauna Kea (4,213 metres [13,822 feet]) on the island of Hawaii in the Northern Hemisphere, and Gemini South, located at the Cerro Tololo Inter-American Observatory on Cerro Pachon (2,725 metres [8,940 feet]) in Chile in the Southern Hemisphere. Alopeke and Zorro have already been used for observations of transients, targets of opportunity (ToOs), time-domain astrophysics, and fundamental stellar astrophysics. In addition to the narrow filters, each wheel has wide-band SDSS (ugriz) filters suitable for broadband photometry and imaging. For reference, the inner diameter of this cylinder is 0.4m with a height of 0.28m. The box housing the optics and components is 0.32m on a side. doi:10.1088/0067-0049/190/1/1, Ramey, E., Lu, J. R., and Yin, R. (2020). The Gemini capsule flew on a Titan II rocket. The Gemini telescopes utilize exquisitely figured 8 m diameter monolithic primary mirrors and each incorporates laser-assisted adaptive optics to greatly improve the image sharpness over what is otherwise available from the ground. The observatory is named after the constellation Gemini, which represents the twins Castor and Pollux. The detector response is >99.9% linear. 1https://www.gemini.edu/instrumentation/alopeke-zorro, 6https://www-star.fnal.gov/Southern_ugriz/New/index.html, 7https://www.gemini.edu/instrumentation/gmos/calibrations, 8http://www.gemini.edu/sciops/instruments/integration-time-calculators/gmoss-itc, Ciardi, D. R., Beichman, C. A., Horch, E. P., and Howell, S. B. 500, 5098. doi:10.1093/mnras/staa3571. TABLE 5. Furthermore, if the system is a multiple star system the derived exoplanet radius will be smaller than in actuality (Ciardi et al., 2015; Furlan and Howell, 2017). Rank the telescopes from left to right based on their light-collecting area from largest to smallest. The Gemini instruments are located between the Instrument Support Structure (ISS) and the Gemini Calibration (GCAL) unit. In Figure 6C, the differential Vm is presented as a function of separation (), which shows that within our typical field of view ( 1), the measured magnitude differences (m) of the binary components are quite consistent across multiple observations, typically to within 0.1 mag. Two new imaging instruments, Alopeke and Zorro, were designed, built, and commissioned at the Gemini-North and Gemini-South telescopes in 2018 and 2019, respectively. Speckle imaging is extremely sensitive to detecting and characterizing angularly close companions (i.e., binary systems) in a single observation and provides the separation, position angle, and color difference of the sources. Due to telescope scheduling targets are most often observed during bright conditions, but typically at seeing better than 1. Nyquist sampling is achieved in the red channel, however the blue channel is slightly undersampled. A series of 60ms exposures were taken in wide-fov mode. The new instruments also take advantage of the sophisticated speckle image reconstruction software for point sources that is largely based on the work of one of us (E.P.H.) Welcome to the new NSF.gov experience. Gemini is a Cassegrain telescope with a maximum 10 arcmin field, so it will be used mostly for deep and detailed measurements over relatively small fields. Gemini consists of two 8-meter telescopes that together can explore the entire northern and southern skies in optical and infrared light. Use this data Three University of Toronto scientists used the Gemini North telescope on Mauna Kea in Hawai'i to take images of the young star 1RXS J160929.1-210524 (which lies about 500 light-years from Earth) and a candidate companion of that star. TABLE 4. The black curves are fits to the 562 and 832nm data. Astronomical J. Masses, Luminosities, and Orbital Coplanarities of the Orionis Quadruple-Star System from Phases Differential Astrometry. (2017). Astronomical J. Some missions stayed in space for a longer time. Also, at times the cameras are removed from the instrument as a precaution during work on other instruments and the camera is placed back at a slightly different focus position. 162, 2. For example, I just tried to connect to my mount via PHD2. 340 3-s exposures were taken to capture the 90s eclipse duration. This can lead to false positive exoplanet detections and improperly determined stellar parameters resulting in incorrect conclusions about exoplanet characteristics. 140, 16231630. A fast and sensitive optical imager on an 8m-class telescope has a multitude of uses beyond speckle interferometry, particularly when it is readily available to the Gemini community. We note that the 562nm observations fall closer to V, as expected. Here, we discuss the third parameter derived from speckle measurements in which a companion is detected, the magnitude difference between the two stars. Gemini North and South made their first observations in 1999 and 2000, respectively. In Figures 6E-H, we present the same sample of calibration binaries but with their measured magnitude differences (m) normalized by subtracting the mean m for each observation. The Frederick C. Gillett Gemini North telescope is located on Hawaii's Mauna Kea as part of the international community of observatories built to take advantage of the superb atmospheric conditions on this long dormant volcano which rises about 4,214 meters (13,824 feet) into the dry, stable air of the Pacific. September 15, 2008 Three University of Toronto scientists used the Gemini North telescope on Mauna Kea in Hawaii to take images of the young star 1RXS J160929.1-210524 (which lies about 500 light . The reduced data products provided to users for TOI 1217. These cuts help to highlight the distribution of the set of contrast curves. A., and Andrade, M. (2013). Soc. By combining the data interferometrically in the frequency domain, each frame contributes to the signal. As described in Horch et al. Note that this differs greatly from image stacking, shift-and-add, or lucky imaging which selects only a small fraction of recorded frames and combines them in the spatial domain. Editors M. J. Creech-Eakman, P. G. Tuthill, and A. Mrand, 1070112. For our particular observing runs, Cerro Pachon had better than average seeing for that site, and this resulted in similar quality data from each instrument. The Gemini South telescope is located at an elevation of 2,737 meters (8,980 feet) on a mountain in the Chilean Andes named Cerro Pachn. Creative Commons Attribution License (CC BY). An SDSS i-band image of the spectroscopic binary beta Del left. Contrast curves that represent the 5 detection limit can then be made from these bins. Min. Observations of Binary Stars With the Differential Speckle Survey Instrument. An individual 60ms exposure speckle frame (top left); during observations data cubes of thousands of such images are collected and individually processed. Astronomical J. The telescopes have adaptive optics systems that compensate for atmospheric turbulence that can blur images. These light curves demonstrate the high cadence observations possible with Alopeke and Zorro. Explain why. The same SDSS i-band image re-sampled to the 21 pixel scale for TESS with an inset showing the scale of the speckle FoV center. Astronomers have unveiled what is likely the first picture of a planet around a normal star similar to the Sun. The time-series light curves were produced from a series of 340 3-sec exposures taken on Feb 1618th (ZTFJ0220 + 2,141) and June 6th and ninth 2020 (NZ Boo). We note from these plots that our narrow-band instrumental photometry generally follows a standard photometric system even as observing conditions change. Each observing sequence generates a FITS file consisting of a 3-D image extension and a binary table extension containing timestamps for each frame in each channel, red and blue. Observations in the paper made use of the High-Resolution Imaging instruments Alopeke and Zorro. The major components of the Gemini instruments are shown in Figure 2. Each FITS file contains 1,000 individual frames of 60ms exposures. NASA made changes to the missile so it could carry people. The maximum readout rate is 30MHz. Gemini Observatory is really one institution with two telescopes: Gemini North is located on Mauna Kea on the Big Island of Hawai'i and Gemini South is on Cerro Pachon in Chile. The telescope mount, a large mechanical, steel structure that holds the mirrors, allows rotational movements of the telescope along a horizontal and vertical axis. Front. A combined global average is also given for each instrument. Each filter wheel is capable of holding six one-inch round filters. doi:10.1088/0004-6256/137/6/5057, Howell, S. B., Matson, R. A., and Ciardi, D. R. (2021a). The known position for observation time 14:49 UTC based on the ephemerides for the satellite is shown and corresponds to frame number 132 in the sequence left. Astronomical J. NS contributed all plots and most text, and is the instrument scientist. (Left) Gemini North with open wind vents and observing slit at sunset. The VSS is the speed at which the rows are shifted down the chip and the HS is the clock rate at which the pixels are read from the gain/shift register. Infrared observations made with ground-based telescopes have long benefited from the use of adaptive optic systems in which deformable mirrors rapidly correct the incoming wave-fronts (Hayward et al., 2001; Hodapp et al., 2003; Ramey et al., 2020). The estimated eclipse duration is 4min. Instrument Description and First Results. 132, 24782488. After every observing run, a fringe-fitting routine is performed on the speckle data for the calibrators. Alopeke and Zorro are two speckle cameras at the Gemini-North and Gemini-South telescopes, respectively, and are available to the community via the peer review proposal process for Gemini based on the host institution. The images shown are from the 716nm filter. The instrument rotator changes the angle of the calibration binary image on the CCD, allowing the pixel scale to be derived at different orientations. Erik Gregersen is a senior editor at Encyclopaedia Britannica, specializing in the physical sciences and technology. Like NESSI, these new instruments are generally based on the Differential Speckle Survey Instrument (DSSI, Horch et al. Telescopes are often used at observation decks to let you see cities in detail from a high point like a skyscraper or a mountain. Astronomical J. From this, a reconstructed diffraction-limited image (bottom right) can be produced [Figure adapted from Scott (2018)]. 117, 10231036. You may select the best match for your required spatial and/or spectral resolution, central wavelength, field-of-view, sensitivity, etc. Measures During 20082009. The U.S.A. and six other countries are participating in the Gemini Telescopes project. The result is a telescope with the same light-gathering ability as a single 11.8-meter mirror, and with the resolution of a 22.8-meter mirrora record for telescopes of this size and type. Alopeke is shown on the left and Zorro on the right. SH, CG, AS, and RS contributed to text. The instruments can also function as conventional CCD imagers providing a 1 arc-minute field of view and allowing simultaneous two-color, high-speed time-series operation. 1999, Neelon Crawford, from Polar Fine Arts, courtesy of Gemini Observatory and NSF. The Gemini North telescope is situated near the summit of Mauna Kea on the island of Hawaii, at an altitude of 4213 m, at latitude 19:49:25.7016 and longitude -155:28:08.616 in the WGS84 system, or at latitude 19:49:25.68521 and longitude -155:28:08.56831 in the NAD83 system (for a complete listing of Mauna Kea telescope coordinates on this syst. Astrophysical J. Suppl. Speckle mode average Pixel Scale and Position Angle difference from orbit empherides prediction for each observing semester. (2017). Typical m uncertainties of 0.02 magnitudes in the blue channel and 0.04 magnitudes in the red channel can be expected for either instrument. 135, 766776. 137, 50575067. The differences mostly arise from the different QE of the detectors, while the iXon Ultra presents a flat QE from 400 to 700nm, slightly outperforming the GMOS/Hamamatsu below 450nm, the Hamamatsu are red-sensitive with a much improved QE over the iXon Ultra above 750nm, explaining the 1 mag difference in z. I. Alopeke and Zorro have a single Ag pickoff mirror whose transmission is also shown here. FIGURE 8. 154, 66. doi:10.3847/1538-3881/aa7b70, Hayward, T. L., Brandl, B., Pirger, B., Blacken, C., Gull, G. E., Schoenwald, J., et al. It is expected that the Large Synoptic Survey Telescope (LSST) will . (2021). Space Sci. Phase II: Requesting & Monitoring Observations, Gemini Telescopes, Science and Technologies, Gemini In The Era of Multi-Messenger Astronomy, Diameter: 8.1 meters/26.58 feet/319 inches, Height: 21.7 meters/71.2 feet/7 stories (from Observing Floor), Height: 46 meters/151 feet/15 stories (from ground). (Right) Gemini South with star-trails of the South Celestial Pole overhead. The collimated beam is incident upon a Semrock manufactured dichroic with a break at 673.7nm. The Gemini telescopes are the only large telescopes in the world with silver-coated primary mirrors. Cameron Winklevoss, co-founder of the Gemini crypto exchange, tweeted what he described as a "final offer" in the debt-restructuring talks over the bankrupt digital-asset firm Genesis, bringing . One telescope was built in each hemisphere so that the Gemini Observatory would not be restricted by geography in the objects that it could observe. The data for these curves were supplied by the respective manufacturers. Zolt Levay (left), senior image processor, and Vanessa Thomas, informal science specialist, review data retrieved from the . Created by Keilani_mp Terms in this set (52) aperture diameter of the primary lens or mirror of a telescope chromatic aberration distortion that causes an image to appear fuzzy when each wavelength coming into a transparent material focuses at a different spot detector The Gemini telescopes use instruments and cameras, plus . A., and Ling, J. F. (2009). Pac. Pac. For speckle mode the primary configuration settings are a region-of-interest (ROI) of 256 square pixels, a 60ms exposure for a series of 1,000 frames per FITS file. Analyzing Long-Term Performance of the Keck-II Adaptive Optics System. Iv. Stellar Companions at 11000 au and Implications for Small Planet Detection. Since a companion was detected for TOI 1217, the results of the accompanying binary fit are given in Table 2. Scott, N. J. The Gemini Observatory is an astronomical project created by the USA, Canada, South Korea, Argentina, Brazil, and Chile. The 466 and 562nm data is shown in blue while the 716 and 832nm data is shown as red. 8, 635864. doi:10.3389/fspas.2021.635864, Kosakowski, A., Kilic, M., and Brown, W. (2021). Illustrative plots showing the relationship between our derived m from Alopeke (blue and red circles) and Zorro (green and pink squares) observations of the calibration binaries compared with V values taken from the WDS catalogue. Although these instruments were built for speckle imaging, in meeting those design requirements our instruments also function as capable high-speed CCD imagers with application in time domain astronomy. Gemini Observatory 01/03 This image features the Gemini North telescope during laser guide star operations (LGS). NSF funds the U.S.A. part of the collaboration and administers the project for the partnership's members. The two-stage Titan II was originally a missile. I have a Losmandy G11GT and I am using gemini telescope.net (ASCOM) to link in all my programs but TSXpro. Binary Star Orbits From Speckle Interferometry. FIGURE 2. A special technique used in radio astronomy is called "interferometry." Radio astronomers can combine data from two telescopes that are very far apart and create images that have the same resolution as if they had a single telescope as big as the distance between the two telescopes. 144, 165. doi:10.1088/0004-6256/144/6/165, Horch, E. P., Casetti-Dinescu, D. I., Camarata, M. A., Bidarian, A., Altena, W. F. v., Sherry, W. H., et al. The highest fps possible with our software setup is a 0.8ms exposure with a 75% deadtime. Copyright 2021 Scott, Howell, Gnilka, Stephens, Salinas, Matson, Furlan, Horch, Everett, Ciardi, Mills and Quigley. https://www.britannica.com/topic/Gemini-Observatory. The two identical instruments are based on the legacy of the DSSI (Differential Speckle Survey Instrument) instrument, successfully used for years at the WIYN and the Gemini telescopes in Hawaii and Chile. Observations Ofkepler,corot, Andhipparcosstars From the Gemini North Telescope. Speckle Observations of TESS Exoplanet Host Stars: Understanding the Binary Exoplanet Host Star Orbital Period Distribution. gemini telescope.net - posted in Equipment (No astrophotography): Hope this is the right forum. Astronomical J. Image reduction and photometry were performed with standard IRAF tools (ccdred, apphot), while the transformation equations were derived with IRAF/photcal. Since GMOS-N lacks a u filter, Alopeke can be a good alternative for point sources or slightly extended sources at this wavelength. Astronomical J. Speckle interferometric imaging and Fourier reconstruction techniques allow ground-based telescopes to produce diffraction limited images (Labeyrie, 1970). The bottom row shows contrast curve cuts at 0.2 and 1.0 for Alopeke and Zorro, respectively. This is what a typical 1minute exposure would look like in these conditions. Astronomical J. Planned engineering work and general upgrades to the telescope, instruments, software etc. For most targets, sets of three to five files are all that is required along with a point spread function (PSF) calibrator observation. This dichroic splits the beam into red and blue components. 148, 63. doi:10.1088/0004-6256/148/4/63, Tokovinin, A., Mason, B. D., Mendez, R. A., Horch, E. P., and Briceo, C. (2019). All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. See Horch et al. The average pixel scale for each observing semester (top left) for Alopeke and Zorro (prefixed with N and S, respectively) in the 562 (blue) and 832 (red)nm filters. The two telescopes have been optimized for observations at infrared wavelengths by having their primary mirrors coated with silver, which does not emit as much thermal infrared radiation as the more commonly used aluminum coatings. Even though Alopeke and Zorro are visitor instruments, there is no collaboration requirement with the instrument team; the team is available for consultations. Relatively large shifts in pixel scale, of 1%, do occur after the instrument has been removed and replaced back on the telescope but are compensated for in each runs pixel scale calibration. (2001). Measures Below the Diffraction Limit of the Wiyn Telescope. The Gemini instruments Alopeke and Zorro have identical cameras and internal components to the NESSI instrument at WIYN (Scott et al., 2018). Dynamical and Physical Properties of 22 Binaries Discovered by W. S. Finsen. Updated Jul 3, 2023 at 3:39 p.m. UTC. The real-world performance has significant additional overheads and variable systematic errors that greatly depend upon the various settings of the camera. Astronomical J. The telescopes employ new mirror technologies that allow large, thin, computer-adjusted mirrors to collect and focus starlight with extraordinary precision. FIGURE 6. Alopeke and Zorro Contrast Curves (top left and right, respectively), a compilation of 1,094 5-sigma contrast curves for data taken from 2019 to mid-2020 in the 466, 562, 716 and 832nm channels. Astronomical J. Binary Stars With Components of Solar Type: 25 Orbits and System Masses. Gemini Observatory consists of the Gemini South telescope on Cerro Pachon in Chile and the Frederick C. Gillett Gemini North telescope on Maunakea, Hawaii. We would not expect this to be a perfect match as we are comparing two different photometric filter systems, but we note the similar trend in the values. The detector is cooled to 60C and read out at 20MHz at a vertical shift speed of 1.13s. To achieve the diffraction limited resolution of a large diameter telescope the corrupting influence of the atmosphere must be addressed. Measures From 2010 September to 2012 February at the WIYN Telescope. Improved Orbital Elements of 22 Visual Systems. The Gemini Speckle InstrumentsAlopeke and Zorro. The target is a crowded field that coincides with the path of the satellite GPS BIIR-2 PRN 13 aka G13. At least once per observing run, a specific calibration binary is observed 9 times in a row while the telescope image rotator is rotated through distinct positions. Observations of Binary Stars With the Differential Speckle Survey Instrument. 10701, Optical and Infrared Interferometry and Imaging VI, Lunar and Planetary Science Conference, Lunar and Planetary Science Conference, 1919, https://doi.org/10.3389/fspas.2021.716560, https://www.frontiersin.org/articles/10.3389/fspas.2021.716560/full#supplementary-material, https://www.gemini.edu/instrumentation/alopeke-zorro, https://www-star.fnal.gov/Southern_ugriz/New/index.html, https://www.gemini.edu/instrumentation/gmos/calibrations, http://www.gemini.edu/sciops/instruments/integration-time-calculators/gmoss-itc. (2015). Astronomical J. The NN-Explore Exoplanet Stellar Speckle Imager: Instrument Description and Preliminary Results. Speckle imaging enables binary/close companion systems with separations from 0.02 to 1.2 to be imaged and directly have their color, separation, and position angle determined. Our editors will review what youve submitted and determine whether to revise the article. A Catalogue of Potential Post Common Envelope Binaries. Speckle Observations of Binary Stars With the Wiyn* Telescope. Figure 3 and Table 1 show the particular filters and the transmission curves for the filters and dichroic used. Within 10 pc the multiplicity rate for M dwarfs was found to be 18 3% at separations less than 2. It is not uncommon for 5060 (bright) science targets and their point source calibrators to be observed in a single night. Typically targets are organized into queue blocks based on proposal rank and hour angle. When their capabilities are fully exploited, we expect similar performance from Alopeke and Zorro. (2011b) for DSSI measurements and can result in an overestimation of the observed magnitude differences between binary companions when the value of times seeing exceeds 0.6 arcsec2. One of their main scientific roles is the validation and characterization of exoplanets and their host stars as discovered by transit surveys such as the NASA Kepler, K2, and TESS missions. A representative sample of the set of calibration binaries used for determining the pixel scale and delta magnitude (brightness ratio) measurements is described in Table 3. A single average pixel scale is determined for each observing run and plotted here along with the standard deviation. A comparison of a single short exposure speckle frame to the equivalent integration of a 1minute exposure (1000 speckle frames) is given in Figure 1. In the middle row are the respective detection contrast limit curves. Figure 6 provides an illustrative comparison between the Alopeke and Zorro measured m values to V values taken from the WDS catalogue. The images obtained produce speckle interferograms that are then correlated in the Fourier domain yielding reconstructed images that have angular resolution at, or even below, the diffraction limit of the telescope (Horch et al., 2006; Horch et al., 2011b). Direct Imaging of Near Earth Object 3200 Phaethon (1983 TB), in Lunar and Planetary Science Conference, Lunar and Planetary Science Conference, 1919. The ISS is a stiff cube that itself houses the Acquisition and Guidance Unit which contains the Acquisition Camera and Peripheral Wavefront Sensors (guiders). This separation and position angle is compared to the separation (in arcseconds) and position angle (PA) determined from the orbital empherides derived from the Washington Double Star Catalog ephemerides.5 From this, a pixel scale (arcsecond/pixel) is determined for each observing run. These instruments are capable of diffraction-limited speckle imaging, have wide-field conventional imaging capability, and are capable of high precision time-domain observations. The PSF standard is typically a bright, single star that is used to calibrate the data in the Fourier reduction pipeline. Color information may also be used in the data reduction process to compensate for atmospheric dispersion, a major source of error at the smallest spatial scales (Horch et al., 2009).
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