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: http://mavr.sao.ru/hq/lsfvo/devices/scorpio/ifp/cubes.html
Дата изменения: Unknown Дата индексирования: Mon May 26 19:01:44 2008 Кодировка: Поисковые слова: martian surface |
Introduction: what is "data cubes"?
![]() This figure shows example of ordinary data cube. Its interference rings of Ne line which use for phase calibration (convert object data to wavelength-scale). | |
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Calibration cubes
Calibration set with Fabry-Perot including standard frames for CCD observation such as BIAS and DARK frames. Moreover will be obtained NEON-line calibration cube and FLAT-FIELD calibration cube for each setting of narrow-band order-separate filter.
NEON cube![]() | Line wavelength is a function of radial distance in each channel of the original OBJECT data cube. Therefore individual spectra in each pixel has a shift along wavelength-axis. Set images of ring picture from the reference emission line of He-Ne-Ar lamp need use for wavelength calibration. NEON data cube is construction from that images. Then a map of phase shifting formed from data cube. |
FLAT-FIELD cube ![]() |
For flat fielding calibration uses the whitelight lamp
with cogtinuous spectra. Flat Field calibration need for two reasons:
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Wavelength calibration
Phase surface ![]() | Phase map is a 2D-image where value of each pixel is corresponding to a relatively shift the calibration emission line's center in NEON data cube. Shape of the emission line is a Airy profile really, but it is approximated as Lorentzian very well. It has a Lorentzian profile in radial direction, and has breaks in regions where interference order takes turn. | |
ORIGINAL OBJECTs CUBE![]() | ORIGINAL NEONs CUBE ![]() | WAVELENTGH's CUBE![]() |
System of rings in the OBJECT original cube is night sky lines. Phase surface are extracted from NEON data cube and uses for wavelength calibration procedure (linearization). Individual spectra in the OBJECT cube are shifted by value of phase shifting and re-scaled to wavelength units. Each channel in the output OBJECT cube like as a image in narrow filters which has FWHM < 1 A. |
The example of wavelength corrected data
Click here for more examples.