UNDERFLIGHT CALIBRATION OF SOHO/CDS AND HINODE/EIS WITH EUNIS-07

Journal Article · Wed Nov 30 23:00:00 EST 2011 · Astrophysical Journal, Supplement Series

DOI:https://doi.org/10.1088/0067-0049/197/2/32· OSTI ID:22047261

Tongjiang, Wang; Brosius, Jeffrey W ^[1]; Thomas, Roger J; Rabin, Douglas M; Davila, Joseph M ^[2]; Young, Peter R ^[3]

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1. Institute for Astrophysics and Computational Sciences (IACS) in the Department of Physics, Catholic University of America, 620 Michigan Avenue NE, Washington, DC 20064 (United States)
2. NASA Goddard Space Flight Center, Code 671, Greenbelt, MD 20771 (United States)
3. College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States)

Flights of Goddard Space Flight Center's Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS) sounding rocket in 2006 and 2007 provided updated radiometric calibrations for Solar and Heliospheric Observatory/Coronal Diagnostic Spectrometer (SOHO/CDS) and Hinode/Extreme Ultraviolet Imaging Spectrometer (Hinode/EIS). EUNIS carried two independent imaging spectrographs covering wavebands of 300-370 A in first order and 170-205 A in second order. After each flight, end-to-end radiometric calibrations of the rocket payload were carried out in the same facility used for pre-launch calibrations of CDS and EIS. During the 2007 flight, EUNIS, SOHO/CDS, and Hinode/EIS observed the same solar locations, allowing the EUNIS calibrations to be directly applied to both CDS and EIS. The measured CDS NIS 1 line intensities calibrated with the standard (version 4) responsivities with the standard long-term corrections are found to be too low by a factor of 1.5 due to the decrease in responsivity. The EIS calibration update is performed in two ways. One uses the direct calibration transfer of the calibrated EUNIS-07 short wavelength (SW) channel. The other uses the insensitive line pairs, in which one member was observed by the EUNIS-07 long wavelength (LW) channel and the other by EIS in either the LW or SW waveband. Measurements from both methods are in good agreement, and confirm (within the measurement uncertainties) the EIS responsivity measured directly before the instrument's launch. The measurements also suggest that the EIS responsivity decreased by a factor of about 1.2 after the first year of operation (although the size of the measurement uncertainties is comparable to this decrease). The shape of the EIS SW response curve obtained by EUNIS-07 is consistent with the one measured in laboratory prior to launch. The absolute value of the quiet-Sun He II 304 A intensity measured by EUNIS-07 is consistent with the radiance measured by CDS NIS in quiet regions near the disk center and the solar minimum irradiance recently obtained by CDS NIS and the Solar Dynamics Observatory/Extreme Ultraviolet Variability Experiment.

• OSTI ID: 22047261
• Journal Information: Astrophysical Journal, Supplement Series, Journal Name: Astrophysical Journal, Supplement Series Journal Issue: 2 Vol. 197; ISSN 0067-0049; ISSN APJSA2
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
79 ASTRONOMY AND ASTROPHYSICS
ASTROPHYSICS
CALIBRATION
CORRECTIONS
DIAGRAMS
EXTREME ULTRAVIOLET RADIATION
EXTREME ULTRAVIOLET SPECTRA
HELIUM IONS
OPERATION
RADIANT FLUX DENSITY
RESPONSE FUNCTIONS
SOLAR RADIATION
SPACE FLIGHT
SUN
ULTRAVIOLET SPECTROMETERS