Invited Article: Deep Impact instrument calibration

被引：37

作者：

Klaasen, Kenneth P. ^{[1
]}

A'Hearn, Michael F. ^{[2
]}

Baca, Michael ^{[3
]}

Delamere, Alan ^{[4
]}

Desnoyer, Mark ^{[5
]}

Farnham, Tony ^{[2
]}

Groussin, Olivier ^{[2
]}

Hampton, Donald ^{[6
]}

Ipatov, Sergei ^{[2
]}

Li, Jianyang ^{[2
]}

Lisse, Carey ^{[7
]}

Mastrodemos, Nickolaos ^{[1
]}

McLaughlin, Stephanie ^{[2
]}

Sunshine, Jessica ^{[2
]}

Thomas, Peter ^{[5
]}

Wellnitz, Dennis ^{[2
]}

机构：

[1] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA

[2] Univ Maryland, Dept Astron, College Pk, MD 20742 USA

[3] Sci Applicat Int Corp, Chantilly, VA 20151 USA

[4] Delamere Support Serv, Boulder, CO 80304 USA

[5] Cornell Univ, Ithaca, NY 14853 USA

[6] Ball Aerosp & Technol, Boulder, CO 80301 USA

[7] Johns Hopkins Univ, Appl Phys Lab, SD SRE, Laurel, MD 20723 USA

来源：

REVIEW OF SCIENTIFIC INSTRUMENTS | 2008年 / 79卷 / 09期

基金：

美国国家航空航天局;

关键词：

D O I：

10.1063/1.2972112

中图分类号：

TH7 [仪器、仪表];

学科分类号：

0804 ; 080401 ; 081102 ;

摘要：

Calibration of NASA's Deep Impact spacecraft instruments allows reliable scientific interpretation of the images and spectra returned from comet Tempel 1. Calibrations of the four onboard remote sensing imaging instruments have been performed in the areas of geometric calibration, spatial resolution, spectral resolution, and radiometric response. Error sources such as noise (random, coherent, encoding, data compression), detector readout artifacts, scattered light, and radiation interactions have been quantified. The point spread functions (PSFs) of the medium resolution instrument and its twin impactor targeting sensor are near the theoretical minimum [similar to 1.7 pixels full width at half maximum (FWHM)]. However, the high resolution instrument camera was found to be out of focus with a PSF FWHM of similar to 9 pixels. The charge coupled device (CCD) read noise is similar to 1 DN. Electrical cross-talk between the CCD detector quadrants is correctable to <2 DN. The IR spectrometer response nonlinearity is correctable to similar to 1%. Spectrometer read noise is similar to 2 DN. The variation in zero-exposure signal level with time and spectrometer temperature is not fully characterized; currently corrections are good to similar to 10 DN at best. Wavelength mapping onto the detector is known within 1 pixel; spectral lines have a FWHM of similar to 2 pixels. About 1% of the IR detector pixels behave badly and remain uncalibrated. The spectrometer exhibits a faint ghost image from reflection off a beamsplitter. Instrument absolute radiometric calibration accuracies were determined generally to <10% using star imaging. Flat-field calibration reduces pixel-to-pixel response differences to similar to 0.5% for the cameras and similar to 2% for the spectrometer. A standard calibration image processing pipeline is used to produce archival image files for analysis by researchers. (C) 2008 American Institute of Physics. [DOI: 10.1063/1.2972112]

引用

页数：77

共 26 条

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