Very Large Telescope and NACO Instrumentation

rattling Large oscilloscope and NACO InstrumentationThis report describes the Very Large Telescope array in Chile, the VLT consists of quartette whole Telescopes with main reverberates of 8.2m diameter and four movable Auxiliary Telescopes with main mirrors of 1.8m diameter.One of the unit of measurement Telescopes, UT 4, is discussed in much detail, specifically its location, mounting, optics, the identify and boil waste locations and the available instruments.The last part of the report is an example of an card planning to substitution class the Becklin-Neugebauer (BN) object with the NACO S13 camera and K band filter.IntroductionThe Very Large Telescope array (VLT) is at this moment the worlds or so advanced optical instrument (1), the VLT is located on the Paranal Observatory, call Figure 1, in the Atacama retract Northern Chile (70 24 11 West 243731 South).The Paranal riding horse is probably the best site for astronomical observations in the southern hemisphere, w ith e.g a humidity of 5-20% and a maximum rainfall of about 100 mm per year.The observatory is divided into two argonas, a cathode-ray oscilloscope platform at the top of the mountain at an elevation of 2635 meters. and a base pack at the foot at an altitude of 2360 m.The observations take place at the telescope platform, the base camp contains staff quarters, maintenance facilities, including a visitorscentre for the public.Overview of the VLTThe VLT consists of four identical Unit Telescopes (UT) with main mirrors of 8.2m diameter and four movable 1.8m diameter Auxiliary Telescopes, located on the telescope platform, see Figure 2 .The Unit Telescopes argon Ritchey-Chrtien telescopes, they can operate in Cassegrain, Nasmyth or Coud focus. The four Unit Telescope have an altitude-azimuth (alt-az) mounting (2).The Unit Telescopes have fixed locations, the Auxiliary Telescopes can be repositioned on 30 different stations, the UT and AT telescopes can be used in some(prenominal) d ifferent sensory systemsindependent telescope modecombined coherent mode or VLT interferometer (VLTI)combined incoherent modeIn the independent telescope mode each UT is used separately, in the combined coherent mode the UT and AT telescopes work together, in groups of two or collar, to form a giant interferometer giving an angular colonisation equivalent to a telescope with a diameter of 200 meters and in the combined incoherent mode the four UTs are combined providing the total light collecting power of a 16-metre single telescope.For the four Unit Telescopes, names of objects in the flip in the Mapuche nomenclature were chosen and they are now known as Antu (UT1, The Sun ), Kuyen (UT2, The Moon ), Melipal (UT3, The Southern Cross ), and Yepun (UT4, Venus as evening star). Unit Telescope 4 (Yepun), see Figure 3 is discussed in more detail in the next sectionThe VLT instruments includes large- playing field imagers, adaptive optics evened cameras and spectrographs, high-reso lution and multi-object spectrographs operating at wavelengths ranging from dense ultraviolet (0.3 nm) to mid-infrared (24 m).With these instruments important data can be collected for a large range of re try topics such asformation and evolution of galaxiessearch for extra-solar planetary systemsdistances to galactic Cepheidscircumstellar plows around young stellar objectsactive galactic nucleistellar evolutionfundamental parameters of the UniverseUnit Telescope 4 ocular set-upUnit Telescope 4 can operate in four foci two Nasmyth, one Cassegrain and one Coud focus (2), for the optical lay-out, including the eight mirrors (M1 to M8) and the main dimensions see Figure 4.Light is collected by the patriarchal mirror M1 and concentrated by the secondary mirror M2 either to the Cassegrain focus below the primary mirror or to one of the two Nasmyth foci, at the side of the telescope.In the Nasmyth configuration the optical layout is of the Ritchey-Chrtien type, the Cassegrain focus how ever is non of the Ritchey-Chrtien type, changing between the two foci kernel repositioning of the secondary mirror and changing the curvature of the primary mirror.By transferring one Nasmyth focus to another location in the telescope basement the Coud focus is obtained (mirror M4 to M8), from the Coud focus the light can be sent to the combination mode focus or to the interferometric focus.The Coud focus is located below the main telescope structure.The primary mirror (M1)The 8.2 m primary mirror of UT4 is made of Zerodur and is 175 mm thick the shape is actively controlled by means of 150 axial forces actuators, the mirror has a central hole of about 1.0 m. .Zerodur is a glass-ceramic made by Schott Glaswerke AG (Mainz, Germany).The secondary mirror (M2)The secondary mirror is a convex increased mirror made of Beryllium with an external diameter of 1.12 metres and a thickness of 50 mm.By changing the position and orientation of the mirror it is possible to correct some optical aberration of the telescope (defocus and decentring coma) and to change the pointing .The secondary mirror is holded by the M2 Unit at the top of the telescope and reflects the light from the M1 mirror towards the M3 plane mirrorThe optical quality depends on the mode of the mirror, if the mirror is in the active mode (active optics correction in operation) , the Central garishness ratio is larger than or equal to 0.98, with an atmospheric coherence length of 250 mm at a wavelength 500 nm.In the passive mode, active optics correction not in operation, the root mean square (RMS) slope error of the surface of the mirror is less than 0.7 arcsec.The tertiary mirror (M3)The tertiary mirror is flat and elliptically cause (890x1260mm2), the mirror is made of Zerodur and produced by Schott Glaswerke AG.In Nasmyth configuration, see Figure 5, the M3 mirror deflects the light beams towards the scientific instruments located at one or the other Nasmyth focus.In Cassegrain configuration, F igure 5, the M3 mirror assembly is remotely flipped in towed position, parallel to the axis of M3 Tower.Mirror M4 to M8 ( the Coud train)The Coud Train is based on a combination of cylindrical and orbicular mirrors, the lightis sent to the Coud Train by mirror 4 (M4) a concave cylindrical mirror in front of the Nasmyth adapter.Relay optics provide an image of the sky at the Coud focus, the relay optics consists of the following mirrorsM5 a concave spherical mirror (R = 8975 mm)M6 a concave cylindrical mirror (R = 290,000 mm) , the cylinder direction is revolvedby 90 with respect to M4M7 a concave spherical mirror ( R = 5176.2mm)M8 a flat mirror.Technical descriptionThe telescope mounting of Unit Telescope 4 (3) is altitude-azimuth (alt-az), the telescope tube moves around a horizontal axis (the altitude axis ), the two bearings which support the telescope tube are mounted on a fork rotating around a vertical axis (the azimuth axis)The telescope tube is a steel structure, supporting at the bottom the primary mirror (M1) , and at the top the M2 Unit, with the secondary mirror, by metallic beams (spiders).Unit Telescope 4 is protected by an enclosure, this enclosure too provides access for operation and maintenance to certain areas of the telescope and a protection against the wind during observations. The telescope is mounted on a concrete free-baseation, the telescope pier. The geographical coordinates of UT4 are latitude 24 37 31.000 South and longitude 70 24 08.000 WestThe structure of Unit Telescope 4 consists of a large flake subassemblies and parts see Figure 6 , some of the main assemblies arethe tube structure with the M2 spiders which hold the M2 unit .the fork structure with two Nasmyth platforms that support the Nasmyth instyruments.the Coud tube that provides the interface to the Coud mirror units.azimuth tracks which support the fork structure.an azimuth platform which provides access for the Cassegrain instrument.SpecificationsAdaptive and ac tive opticsUT4 has adaptive optics (AO) correction both at Nasmyth and at Cassegrain foci, UT4 is also equipped with a sodium laser transport star facility for active optics.For the non-AO telescope operation the Central Intensity proportion (CIR) quantifies the image quality. A high CIR implies high signal throughput, high contrast and small image size.The peak signal in the long-exposure point sp withdraw conk out is given by (4) equalitywhere is ta the transmissivity of the atmosphere, r0 the coherent wave-front size, tt the transmissivity of the telescope optics, D the diameter of the telescope and CIR the Central Intensity balance.The Central Intensity Ratio define by equatingwhere y0 is the Strehl ratio of the telescope. (Strehl ratio is the ratio of peak diffraction intensities of an aberrated wavefront versus a perfect wavefront).The optical quality specification is that the Central Intensity Ratio CIR = 0.82 with a coherent wave-front of size r0 = 500 mm (seeing angle 0 .2 arcsec) at = 500 nm.Field of viewThe total field of view (FOV) for UT4 in the Cassegrain focus is 15 arcmin, in the Nasmyth focus 30 arcmin and in the Coud focus 1 arcmin.Atmospheric dispersionThe atmospheric dispersion is corrected up to zenith angles of 50 for instruments requiring high image and spectrophotometric quality.Pointing and trackingUT4 is able to get any mark to within 70 zenith distance in less than 3 minutes. Offset pointing of 45 and 60 in altitude and azimuth respectively is possible within 35 seconds, to within 0.1 arcsec accuracy.UT4 tracks better than 0.05 arcsec RMS over a plosive of 15 seconds without employ guide-star position information, and over a one hour period when using guide-star tracking.Zenith distanceThe UT4 can operate at zenith distances ranging from 0.5 to 70, obstruction by neighboring enclosures is limited to zenith angles larger than 60.InstrumentationThe instruments that are mounted on Unit Telescope 4 are shown in table 1.HAWK-IHAWK- I is a near-infrared (0,85 2.5m) wide-field imager installed at the Nasmyth A focus of UT4 , the operating temperature of the instrument is 120 K, operating temperature of the detectors is of 80 K (3).HAWK-I has 10 observing filters placed in two filter wheels Y, J, H, Ks , 6 narrow-band filters Brg, CH4, H2 and three cosmological filters at 1.061, 1.187, and 2.090 m.SINFONISINFONI is a near-infrared (1-2.5 m) integral field spectrograph installed at the Cassegrain focus of UT4.The spectrograph works with 4 gratings J, H, K, H+K with spectral resolutions of R is 2000, 3000 and 4000, corresponding to the J, H and K gratings respectively, and R is1500 with the H+K grating. The resolution power R of a spectrograph is given by Equationwhere c is the velocity of light and dv the radial velocity .NACO (NAOS + CONICA)The Nasmyth Adaptive Optics System (NAOS) and the High Resolution Near IR Camera (CONICA) are installed at the Nasmyth B focus of UT4. NACO provides adaptive-optics correcte d imaging, polarimetry, spectroscopy, and coronagraphy in the 1-5 m range.The NACO instrumentation will be discussed in more detail in the next section.Laser Guide tetherThe Laser Guide Star is an artificial source, a 4W CW Sodium Laser (589 nm) will be used for this. The laser beam is focussed at an altitude of 90 km, at that height an atomic sodium layer is present which backscatters the spot image, producing an artificial star with a magnitude range from 11 mag. to 14 mag.NACO instrumentationInstrument characteristicsNAOSNAOS is an adaptive optics (AO) system that has been designed to work with natural guide stars (NGS) and moderately extended sources , NAOS can also use the laser guide star facility (LGSF) and a natural tip-tilt source (TTS) to provide adaptive optics correction (3).NAOS gives a upheaval corrected f/15 beam and a 2 arcmin field of view to CONICA. Two off-axis parabolas re-image the telescope pupil on the deformable mirror and the Nasmyth focal plane on the entr ance focal plane of CONICA.A dichroic-filter splits the light between CONICA and the wave front sensor, a field call foror is placed after the wave front sensor input focus to select the reference object for wave front sensing, see Figure 7.NAOS has two wavefront sensors one visible light and one near-IR sensor , the two sensors are of the Shack-Hartmann type. It is possible to select an off-axis natural guide star within a 110 arcsec diameter field of view (FOV). NAOS allows wave front sensing with go natural guide stars and extended objects, observations of very bright objects are possible with the visible wave front sensor using neutral density filters.CONICACONICA is an infra-red (IR) (1 5 m) imager and spectrograph which is fed by NAOS.CONICA is capable of imaging, long slit spectroscopy, simultaneous differential imaging (SDI), coronagraphy, polarimetry , with a large range of plate scales, filters and masks.The CONICA detector is a InSb Aladdin 3 array, the parameters of t he array areformat 10261024 pixelspixel size 27mdark current 0.05-0.15 ADUs-1 pixel-1wavelength range 0.8-5.5 mQuantum efficiency 80-90 %The detector has three readout modes and four detector modes .The readout modes refer to the way the array is read out, the read our modes are UncorrThe array is reset and then read once, used for situations when the background is high.The stripped-down detector integration m (DIT) is 0.1750 seconds.Double_RdRstRdThe array is read, reset and read again, used for situations when the background is intermediate between high and low.The minimum DIT is 0.3454 seconds.FowlerNsampThe array is reset, read four periods at the beginning of the integration ramp and four times again at the end of the integration ramp. Each time a pixel is addressed, it is read four times. This is used for situations when the background is low.The minimum DIT is 1.7927 seconds.The detector mode refers to the setting of the array bias voltage, four modes have been defined Hig hSensitivity, HighDynamic, HighWellDepth and HighBackground.HighSensitivity has the fewest hot pixels, but it has the smallest well depth, this mode is used for long integrations in low background situations.HighBackground has the largest well depth but has many more hot pixels, this mode is used in high background situations .S13 cameraCONICA is equipped with several cameras such as S13, S27, S54, the characteristics of camera S13 are scale 13.221 0.017 mas/pixel, field of view (FoV)1414 arcsec and spectral range 1.0-2.5 m.Available filters for the S13 camera are broad- and narrowband filters in the 1-2.5 m expanse,Information on the broadband filters can be found in table 1.Unit Telescope 4 parametersExample observation planningThe observation planning contains the next subjects (5)targetscientific name and address visibleness period of targetmandatory observing conditionsseeingatmospheric transparencylunar illuminationrequired observing timelist of required instruments, modes a nd configurations posteriorThe chosen observation target is the Becklin-Neugebauer (BN) object located in the Orion Nebula Cluster, coordinates right ascension (RA) 05h 35 m 14s.117 and declination (D) -05 2222.90, epoch 2000.0,Scientific goalThe Becklin-Neugebauer object was discovered as a bright 2 m infra-red source (10) by Becklin and Neugebauer in 1967 (11), about 45 in projection from the trapezium bone stars of the Orion Nebula Cluster, at a distance of 450 pc.The Becklin-Neugebauer object together with the Kleinmann-Low nebula (KL) is part of the Orion Molecular Cloud 1 (OMC-1) region, a high-mass star formation region in the Orion constellation.In 2004 Shuping, Morris and Bally (8) discovered, at 12.5m, an arc of emission associated with the BN object, the so-called BN SW arc.The nature of this SW arc is still unknown, it may be externally heated gas or dust by UV radiation or is possibly a compressed shell created by an fountain or jet from BN.The BN SW arc is an intere sting feature that needs further investigations both imaging and spectroscopy at other wavelengths to determine its accredited nature.Required observing conditionsSeeing/airmassSeeing is defined as the image full width half maximum (FWHM )in arcsec ,the seeing values are 0.8and 1.2 at Zenith.Airmass quantifies the effects of all atmospheric processes, these atmospheric effects will be minimum when radiation travels vertically through the atmosphere, in this case z = 1.During the observation period the airmass ranges between z = 1.0 and z = 1.5 see table A, appendix 1, average airmass z = 1,2.Atmospheric transparencyDuring the observation period there should be no visible clouds and the transparency variations should be less than 2%.Lunar illuminationLunar illumination (FLI) is defined as the fraction of the lunar disk that is illuminated at local (Chile) civil midnight, where 1.0 is fully illuminated.Dark time corresponds to slug illumination less than 0.4, so the best time to obs erve the target is when the moon is new, see subsection 7.4.Visibility period of targetTo calculate the visibility of the target I have used the local sidereal time equationEquationwhere LST = local sidereal, HA = hour angle and RA = right ascension.RA of BN-object = 05h 35 m 14s.117 = 5.587 hr. , on 21 edge RA = 12hr is on the meridian at local midnight.RA = 5.587 hr will be on the meridian at local midnight about (5.587-12.0)-30/2 = 96 days = 3 months earlier . Thus the target will be well placed in November 2011 and December 2011.New Moon is on 25 November 2011 and 24 December 2011, so the best dates to observe the BN- object will be 22-27 November and 22-26 December 2011, see table B, appendix 2.The chosen observation period is the night of 24/25 December 2011, between 22hr and 2hr local time.Required observing timeAngular resolutionThe theoretical angular limit of resolution is given byEquationwhere l = wavelength, D = aperature diameterThe wavelength of the K-filter is l = 2 .18 m, so the resolution isThe resolution however is limited by atmospheric turbulence towhere r0 is the Fried parameter.The Fried parameter is directly linked to the strength of the turbulence and it depends on the wavelength asEquationfor average observing conditions, r0 is about 0.6 m at 2.2 m.Seeing diskThe angular diameter of the seeing disk isEquationso for l = 2.18 m and r0 = 0.6 mArea of seeing disk characterization timeExposure time Equationwhere t = integration timer = signal to noise ratiof = mingle transmitted by atmospherefsky = sky background fluxa = area of seeing discA = effective area of telescope UT4Q = quantum efficiencyl = flux of the BN objectl = wavelength = 5.510-7 mh = Plancks constant = 6.6310-34 Jc = velocity of light = 3.0108 ms-1The adopted signal to noise ratio S/N = r = 5.The flux transmitted by the atmosphere f = 1.0, see figure 3.2 NACO User Manual (3)The liming sky background magnitude is 13.0 mag (3), the sky background fluxEquationArea of seeing d isk a = 0.442 arcsecEffective area of UT4Quantum efficiency Q = 0.85The magnitude of the BN object corrected for extinction mv = 5.2 mag (11), the extinction in the V passband Av = 18 mag. (8) so the apparent magnitude of the BN object m = 23.2 mag.Flux /magnitude conversionEquationThe flux of the BN object isThe exposure time for the BN object ist = 639 sec.The exposure time calculated with ETC is 122,320 seconds ? , see appendix 4 table D.List of required instruments, modes and configurationsThe required telescope to observe the BN object is UT4 with the NACOS instrumentation.The NAOS with natural guide star, the CONICA imager with camera S13 and broadband filter K (2.18 mm).The chosen detector readout mode is FowlerNsamp and not Double_RdRstRd because the intergration time is larger than 60 seconds.Guide star id. 0477400932, RA 05hr 35m 16s.41, Dec -05 23 23.0 magnitude 5.00 see table C, appendix 3,ConclusionThe Very Large Telescope array is at this moment the most advanced optic al instrument and the most productive individual ground-based observatory in the world.The instrumentation programme is the most ambitious programme for a single observatory and because of to the outstanding angular resolution and the use of adaptive optics VLT opens a new era of discoveries.Bibliography/ReferencesESO http//www.eso.org/sci/facilities/paranalGiacconi R. The VLT White go forESOhttp//www.eso.org/public/products/books/vlt_whitebook/Girard J. et al. Very Large TelescopeNACO Users ManualDo. No. VLT-MAN-ESO-14200-2761Date 12-02-2010http//www.eso.org/sci/facilities/paranal/instruments/naco/doc/VLT-MAN-ESO-14200-2761_v86.0.pdfDierickx P., et al The VLT primary mirrors mirror production and measured performancehttp//www.eso.org/sci/facilities/paranal/telescopes/ut/m1unit.htmlde Zeeuw T. Call for ProposalsESO Period 8730 August 2010http//www.eso.org/sci/observing/proposals/CfP87.pdfMoorwood A. Astronomical NewsReport on the ConferenceScience with the VLT in the ELT EraHeld in Garching, Germany8-12 October 2007Minchin N.R. et al Near-infrared imaging polarimetry of bipolarNebulae-I. The BN-KL region of OMC-1Mon. Not. R. astr. Soc.(1991) 248,715-729Shuping R. Y., Morris M. and Bally J. A new mid-infra red map of the BN/KLRegion using the Keck telscopeThe Astronomical Journal, 128363-374, 2004 JulySansom A. UVOIR astronomy AA2053University of Central Lancashire , 2010 erythema solare J. The Becklin-Neugebauer Object as runaway B starejected 4000 years ago from the q1C system.The Astrophysical Journal Letters11-12-2001http//arxiv.org/abs/astro-ph/0401552v2Robberto M. et al The Orion Nebula in the mid-infraredThe Astronomical Journal, 129000-0002005 MarchBecklin E.E., Neugebauer G. Observations of an infrared star in the OrionNebulaCalifornia Institute of TechnologyPasadena, CaliforniaSeptember 12,1966http//adsabs.harvard.edu/abs/1967ApJ147..799BTestor G. et al VLT/NACO near-infrared imaging andspectroscopy of N159-5 in the LMC HII complex N159Astronomy Ast rophysics469, 459-469 (2007)AppendicesAppendix 1Hourly airmasses for 05 35 14.12 -05 22 22.90Paranal Observatory (VLT)Sat, December 24, 2011*** Hourly airmass for Target ***Epoch 2000.00 RA 5 35 14.1, dec -5 22 23Epoch 2011.98 RA 5 35 49.5, dec -5 21 57At midnight UT date 2011 Dec 25, Moon 0.00 illum, 151 degr from objLocal UT LMST HA secz par.angl. SunAlt MoonAlt HelCorr22 00 1 00 2 31 -3 05 1.502 -118.5 -4.2722 30 1 30 3 01 -2 35 1.341 -121.5 -4.3223 00 2 00 3 31 -2 04 1.229 -126.1 -4.3823 30 2 30 4 01 -1 34 1.152 -132.8 -4.430 00 3 00 4 32 -1 04 1.101 -142.9 -4.500 30 3 30 5 02 -0 34 1.071 -157.8 -4.561 00 4 00 5 32 -0 04 1.059 -177.2 -4.621 30 4 30 6 02 0 26 1.066 162.7 -4.692 00 5 00 6 32 0 56 1.090 146.5 -4.75Table A Hourly airmasss during observation period.SkyCalc provided by courtesy of John Thorstensen, Dartmouth College. emailprotectedhttp//www.eso.org/sci/observing/tools/calendar/observability.htmlAppendix 2Observability for 05 35 14.117 -05 22 22.90Par anal Observatory (VLT)RA dec 5 35 14.1, -5 22 23, epoch 2000.0Site longlat +4 41 36.8 (h.m.s) West, -24 37 30 North.Shown local eve. date, moon phase, hr ang and sec.z at (1) eve. twilight,(2) natural center of night, and (3) morning twilight then comes number ofnighttime hours during which object is at sec.z less than 3, 2, and 1.5.Night (and twilight) is defined by sun altitude Date (eve) moon eve cent morn night emailprotectedHA sec.z HA sec.z HA sec.z 2011 Oct 11 F -8 54 down -4 28 2.5 -0 02 1.1 4.7 3.9 3.02011 Oct 26 N -7 45 down -3 31 1.7 +0 42 1.1 5.4 4.6 3.82011 Nov 10 F -6 33 down -2 32 1.3 +1 29 1.1 6.2 5.4 4.52011 Nov 24 N -5 25 5.7 -1 34 1.2 +2 17 1.3 7.0 6.2 5.32011 Dec 9 F -4 13 2.2 -0 29 1.1 +3 15 1.6 7.4 7.2 6.12011 Dec 24 N -3 05 1.5 +0 37 1.1 +4 19 2.4 7.4 7.0 6.12012 Jan 8 F -2 02 1.2 +1 44 1.2 +5 30 6.3 6.8 6.0 5.1Table B Observability of Becklin-Neugebauer objectSkyCalc provided by courtesy of John Thorstensen, Dartmouth College. emailprotectedhttp//www.eso.org/ sci/observing/tools/calendar/observability.htmlAppendix 3ESO GSC Online Server Query ResultCenterRA 053514.117DEC -052222.90 search radius20 arcminutesnr gsc_id ra (2000) dec mag mu d pa1 0477400932 05 35 16.41 -05 23 23.0 5.00 F 1.15 1502 0477400931 05 35 16.47 -05 23 22.8 5.09 F 1.16 1503 0477400933 05 35 22.83 -05 24 57.8 5.09 F 3.37 1404 0477400871 05 35 17.10 -05 23 40.6 5.51 F 1.49 1505 0477400934 05 35 26.27 -05 24 58.2 6.40 F 3.98 1316 0477400930 05 35 17.16 -05 23 12.7 6.69 F 1.12 1387 0477801369 05 35 54.09 -05 37 43.2 7.09 T 18.28 1478 0477400906 05 35 31.37 -05 16 02.7 7.19 T 7.65 349 0477400906 05 35 31.26 -05 16 02.0 7.58 T 7.65 3410 0477801369 05 35 53.99 -05 37 42.1 7.74 T 18.25 14711 0477400935 05 35 31.33 -05 25 14.1 8.18 F 5.15 12412 0477400915 05 35 06.10 -05 12 15.5 8.28 F 10.32 34913 0477400809 05 34 46.89 -05 34 14.3 8.30 F 13.66 21014 0477400849 05 35 09.73 -05 27 52.6 8.53 F 5.60 19115 0477400823 05 34 55.20 -05 30 21.7 9.04 F 9.27 21116 0477400867 05 35 58 .44 -05 22 31.0 9.11 F 11.03 9117 0477400855 05 36 27.09 -05 24 31.0 9.28 F 18.29 9718 0477400792 05 34 42.19 -05 07 14.2 9.39 T 17.10 33219 0477400894 05 35 34.18 -05 06 20.9 9.45 F 16.79 1720 0477400830 05 35 18.12 -05 03 54.5 9.48 F 18.50 321 0477400792 05 34 42.19 -05 07 14.3 9.55 T 17.10 33222 0477400890 05 35 31.28 -05 33 08.5 9.74 F 11.58 15823 0477400829 05 35 35.71 -05 12 20.5 9.78 F 11.39 2824 0477400877 05 35 21.17 -05 09 15.7 9.79 F 13.24 825 0477400812 05 35 00.05 -05 25 15.7 9.85 F 4.53 23126 0477400878 05 34 52.14 -05 33 08.1 9.96 F 12.06 20727 0477400810 05 34 49.89 -05 18 44.4 9.96 F 7.04 301gsc 1.0 25/Sep/1995.ESO/ST-ECF Archive ESO ST-ECF Help SearchSend comments to HYPERLINK http//archive.eso.org/comments/emailprotected/Page/cgi-bin/gsc.Table C Guide stars Becklin-Neugebauer object