共查询到20条相似文献，搜索用时 231 毫秒
1.
The imager of the infrared satellite ISO will allow spectral imaging under very low flux conditions in the two to-eighteen-microns range, close to the fundamental limit of the zodiacal background photon noise. To optimize the performance of the imager, we must use an internal calibration device, mainly to track changes in the responsivity of the pixels of the detectors arrays, the limit of detection greatly depending upon the quality of the flat field corrections in certain cases.The first section introduces ISO and its infrared imager and emphasizes the necessity of in-flight calibration. The following chapter presents the specifications for the internal calibration device. The chosen design for the flight model which consists of an infrared emitter and two integrating spheres, is presented in the third chapter. The last part describes the cryogenic bench dedicated to relative photometric tests, the absolute calibration is made in the camera. Endly we present the results obtained with this facility and final tests to achieve the qualification of the device. 相似文献
2.
R. Melchiorri F. Capaccioni A. Coradini G. Filacchione G. Piccioni M. De Petris 《New Astronomy》2004,9(8):635-640
Satellite instrumentations designed for planetary studies are often open to other interesting applications from ground: not only one can efficiently carry out detailed calibrations before space data become available, but also the prototypes of the satellite instruments can be successfully employed in different fields ranging from astrophysics to cosmology. Both possibilities are opened by coupling these instruments with ground based telescopes having short focal ratios, like those designed for far infrared studies. These possibilities are particularly amazing in view of the long delay usually present between the launch and the collection of the first scientific data (months in case of Mars Express, years in case of Rosetta).
We propose in this article to employ immediately this technology, by coupling the developing model of the Image-Spectrometer VIRTIS-M with the ground telescope MITO.
This project will allow us to perform a better calibration of the space qualified instrument and observational campaigns, including some important cosmological investigations. 相似文献
3.
R. Wachter J. Schou M. C. Rabello-Soares J. W. Miles T. L. Duvall Jr. R. I. Bush 《Solar physics》2012,275(1-2):261-284
We describe the imaging quality of the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) as measured during the ground calibration of the instrument. We describe the calibration techniques and report our results for the final configuration of HMI. We present the distortion, modulation transfer function, stray light, image shifts introduced by moving parts of the instrument, best focus, field curvature, and the relative alignment of the two cameras. We investigate the gain and linearity of the cameras, and present the measured flat field. 相似文献
4.
Thomas P. Sparn Gary Rottman Thomas N. Woods Brian D. Boyle Richard Kohnert Sean Ryan Randall Davis Robert Fulton William Ochs 《Solar physics》2005,230(1-2):71-89
The Solar Radiation and Climate Experiment, SORCE, is a satellite carrying four scientific instruments that measure the total
solar irradiance and the spectral irradiance from the ultraviolet to the infrared. The instruments were all developed by the
Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado, Boulder. The spacecraft carrying and accommodating
the instruments was developed by Orbital Sciences Corporation in Dulles, Virginia. It is three-axis stabilized with a control
system to point the instruments at the Sun, as well as the stars for calibration. SORCE was successfully launched from the
Kennedy Space Center in Florida on 25 January 2003 aboard a Pegasus XL rocket. The anticipated lifetime is 5 years, with a
goal of 6 years. SORCE is operated from the Mission Operations Center at LASP where all data are collected, processed, and
distributed. This paper describes the SORCE spacecraft, integration and test, mission operations, and ground data system. 相似文献
5.
Elhanan Almoznino Noah Brosch Ido Finkelman Hagai Netzer Erez R. Yacoby Jeremy Topaz Nachman Saar 《Astrophysics and Space Science》2009,320(4):321-341
We describe in detail the procedures used for the ground testing and calibration of the flight model of the TAUVEX space telescope.
We present the measurements done for this purpose, the various assumptions adopted during the ground calibration process,
the results obtained, and provide a first approximation to the real performance of the experiment.
The results of the ground-based calibration are that the system complies with the predicted performance in all aspects except
for the total throughput, which is a factor of ∼5 smaller than expected. However, the instrument sensitivity measurement is
highly uncertain due to known limitations of the available equipment and a more accurate calibration will be performed in
orbit. 相似文献
6.
P. Barthol A. Gandorfer S. K. Solanki M. Sch��ssler B. Chares W. Curdt W. Deutsch A. Feller D. Germerott B. Grauf K. Heerlein J. Hirzberger M. Kolleck R. Meller R. M��ller T. L. Riethm��ller G. Tomasch M. Kn?lker B. W. Lites G. Card D. Elmore J. Fox A. Lecinski P. Nelson R. Summers A. Watt V. Mart��nez?Pillet J. A. Bonet W. Schmidt T. Berkefeld A. M. Title V. Domingo J. L. Gasent?Blesa J. C. del Toro?Iniesta A. L��pez?Jim��nez A. ��lvarez-Herrero L. Sabau-Graziati C. Widani P. Haberler K. H?rtel D. Kampf T. Levin I. P��rez?Grande A. Sanz-Andr��s E. Schmidt 《Solar physics》2011,268(1):1-34
7.
A. R. Rao M. H. Patil Yash Bhargava Rakesh Khanna M. K. Hingar A. P. K. Kutty J. P. Malkar Rupal Basak S. Sreekumar Essy Samuel P. Priya P. Vinod D. Bhattacharya V. Bhalerao S. V. Vadawale N. P. S. Mithun R. Pandiyan K. Subbarao S. Seetha K. Suryanarayana Sarma 《Journal of Astrophysics and Astronomy》2017,38(2):33
Charged Particle Monitor (CPM) on-board the Astrosat satellite is an instrument designed to detect the flux of charged particles at the satellite location. A Cesium Iodide Thallium (CsI(Tl)) crystal is used with a Kapton window to detect protons with energies greater than 1 MeV. The ground calibration of CPM was done using gamma-rays from radioactive sources and protons from particle accelerators. Based on the ground calibration results, energy deposition above 1 MeV are accepted and particle counts are recorded. It is found that CPM counts are steady and the signal for the onset and exit of South Atlantic Anomaly (SAA) region are generated in a very reliable and stable manner. 相似文献
8.
T. Hilbig M. Weber K. Bramstedt S. Noël J. P. Burrows J. M. Krijger R. Snel M. Meftah L. Damé S. Bekki D. Bolsée N. Pereira D. Sluse 《Solar physics》2018,293(8):121
This paper describes a new reference solar spectrum retrieved from measurements of the satellite instrument SCIAMACHY in the wavelength region from \(0.24~\upmu\mbox{m}\) to \(2.4~\upmu\mbox{m}\) and its comparison with several other established solar reference spectra. The SCIAMACHY reference spectrum was recorded early in the mission before substantial optical degradation due to the harsh space environment sets in. The radiometric calibration of SCIAMACHY, applied in this study, includes a physical model of the scanner unit. Furthermore, SCIAMACHY’s internal white light source (WLS) is used to correct for on-ground to in-flight changes. The resultant calibrated solar spectrum from SCIAMACHY is in good agreement with several available solar spectral irradiance (SSI) references in the visible spectral range. Strong throughput losses due to detector icing in the near infrared (NIR) are now adequately accounted for. Nevertheless, a deficit with respect to the ATLAS-3 composite and SORCE/SIM SSI is observed in the NIR. However, the SCIAMACHY solar reference spectrum agrees well with the recently re-evaluated SOLAR/SOLSPEC-ISS and recent ground measurements taken at Mauna Loa in the NIR. 相似文献
9.
We report a new approach to the calibration of the radiometric asteroid scale using the recent accurate occultation measurements of the diameters of 2 Pallas and 3 Juno, and the Voyager diameter of J4 Callisto, and new infrared photometry of these objects obtained with the NASA 3-m Infrared Telescope Facility. This calibration is internally consistent to better than 5% and probably has an absolute accuracy of ±5%. A revision of the TRIAD radiometric diameters downward is required to bring them into agreement with the new calibration. 相似文献
10.
11.
H.-U. Kaeufl T. Bonev H. Boehnhardt Y. R. Fernandez C. Lisse 《Earth, Moon, and Planets》2005,97(3-4):331-339
Comet 9P/Tempel 1, the target of the Deep Impact mission, has been intensively observed for a long time period before the encounter. Pre-impact ground based monitoring of the comet was an important prerequisite for the success of the first space experiment in which a comet is treated by an artificial impact. It provided the background data needed to disentangle the features caused by the impact from variations caused by the natural activity of the comet. In this paper we present results from the ESO-monitoring of the comet, conducted in the thermal infrared and optical spectral ranges during several months before the Deep Impact encounter with the comet. 相似文献
12.
13.
A total mass 1014 g added to the Earth's upper atmosphere in the form of small particles of high albedo for visual wavelengths would produce an inverse greenhouse effect, shielding ground level from sunlight but permitting infrared radiation from the ground to escape into space. Such a mass of small particles might be acquired by the Earth in a close approach to a cometary nucleus. Ice ages and ecodisasters, such as that which occurred 6.5×107 years ago, could arise from the effects of such an addition of small particles.Supported in part by the National Science Foundation [PHY76-83685] at Caltech. 相似文献
14.
High sensitivity infrared detectors made from extrinsic semiconductors are used for astronomical applications on satellite missions in the earth orbit. High energy radiation reduces the sensitivity and changes the calibration of these photoconductors drastically. This process is reversible through on board annealing. Laser emission of mid infrared diode lasers was used for efficient annealing with low power dissipation. 相似文献
15.
An atlas of high resolution (R = 60 000) CCD-spectra in the wavelength range 3500-5000A is presented for four objects in metallicity range -3.0 < [Fe/H] < -0.6, temperature range 4750 < Teff < 5900 K, and surface gravity range 1.6 < lgg < 5.0. We describe the calibration of the stellar atmospheric parameters using Alonso's formula based on the method of infrared flux and outline the determination of the abundances of a total number of 25 chemical elements. An analysis of the abundance determination errors for different chemical elements is carried out, and a method is provided for the observations and reduction of spectral material. Properties of the method of producing an atlas of spectra and line identifications are described. 相似文献
16.
We describe a flagging and calibration pipeline intended for making quick look images from GMRT data. The package identifies and flags corrupted visibilities, computes calibration solutions and interpolates these onto the target source. These flagged calibrated visibilities can be directly imaged using any standard imaging package. The pipeline is written in ??C?? with the most compute intensive algorithms being parallelized using OpenMP. 相似文献
17.
Ian S. McLean 《Experimental Astronomy》2002,14(1):25-32
The advent of solid-state imaging devices transformed astronomy. Beginning with the introduction into astronomy of charge-coupled
devices in 1976, followed a decade later by infrared arrays, astronomers gained access to near-perfect imaging devices. The
consequences have been nothing short of revolutionary, perhaps especially so in the infrared. Witness, for example, the spectacular
pictures from the Hubble Space Telescope cameras, or the impressive infrared imagery from the 2MASS project. Within the last
decade CCD formats deployed or planned for use in ground-based cameras have become huge. Infrared mosaics, stimulated by the
Next Generation Space Telescope, are coming soon. In addition, new technologies such as CMOS (Complementary Metal Oxide Semiconductors)
and STJs (Superconductiong Tunnel Junctions) are being developed and the future of astronomical detectors looks very exciting,
especially in an era of giant telescopes performing at their diffraction-limit.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
18.
Wenda Cao Klaus Hartkorn Jun Ma Yan Xu Tom Spirock Haimin Wang Philip R. Goode 《Solar physics》2006,238(1):207-217
We discuss a near-infrared (NIR) narrow-band tunable birefringent filter system newly developed by the Big Bear Solar Observatory (BBSO). This is one of the first narrow-bandpass NIR filter systems working at 1.56 μm which is used for the observation of the deepest solar photosphere. Four stages of calcite were used to obtain a bandpass of 2.5 Å along with a free spectral range (FSR) of 40 Å. Some unique techniques were implemented in the design, including liquid crystal variable retarders (LCVRs) to tune the bandpass in a range of ±100 Å, a wide field configuration to provide up to 2° incident angle, and oil-free structure to make it more compact and handy. After performing calibration and characteristic evaluation at the Evans Facility of the National Solar Observatory at Sacramento Peak (NSO/SP), a series of high-resolution filtergrams and imaging polarimetry observations were carried out with the Dunn Solar Telescope of NSO/SP and the 65-cm telescope of BBSO, in conjunction with the high-order adaptive optics system and the Fabry–Pérot Interferometer (FPI). In this paper, we describe the optical design and discuss the calibration method. Preliminary observations show that it is capable of serving as either a stand-alone narrow-band filter for NIR filtergram observations or an order-sorting filter of a FPI applied to NIR two-dimensional imaging spectro-polarimetry. 相似文献
19.
Ch. Haniff 《Astrophysics and Space Science》2003,286(1-2):163-170
The opportunity to deliver high-angular resolution model-independent images is one of the most attractive prospects for optical/infrared
interferometry. In this paper I use simple imaging simulations to identify some of the practical difficulties that may arise
in achieving this goal with the VLTI. For the types of studies investigated here – stellar surface imaging and the mapping
of emission line disks – it is likely that the key challenges will be to measure the visibility function on a sufficiently
large range of baselines, and to secure accurate and reliable phase information.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
20.
R. Neuhuser E.W. Guenther J. Alves N. Hulamo Th. Ott A. Eckart 《Astronomische Nachrichten》2003,324(6):535-542
We present deep high dynamic range infrared images of young nearby stars in the Tucana/Horologium and β Pic associations, all ∼10 to 35 Myrs young and at ∼10 to 60 pc distance. Such young nearby stars are well‐suited for direct imaging searches for brown dwarf and even planetary companions, because young sub‐stellar objects are still self‐luminous due to contraction and accretion. We performed our observations at the ESO 3.5m NTT with the normal infrared imaging detector SofI and the MPE speckle camera Sharp‐I. Three arc sec north of GSC 8047‐0232 in Horologium a promising brown dwarf companion candidate is detected, which needs to be confirmed by proper motion and/or spectroscopy. Several other faint companion candidates are already rejected by second epoch imaging. Among 21 stars observed in Tucana/Horologium, there are not more than one to five brown dwarf companions outside of 75 AU (1.5″ at 50 pc); most certainly only ≤5% of the Tuc/HorA stars have brown dwarf companions (13 to 78 Jupiter masses) outside of 75 AU. For the first time, we can report an upper limit for the frequency of massive planets (∼10 Mjup) at wide separations (∼100 AU) using a meaningfull and homogeneous sample: Of 11 stars observed sufficiently deep in β Pic (12 Myrs), not more than one has a massive planet outside of ∼100 AU, i.e. massive planets at large separations are rare (≤9%). (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献