The use of extra-solar stars as a standards laboratory to test the instrumentation of space missions to facilitate in situ calibration is discussed. Calibrated lightcurves of Arcturus can be used to aid in reducing the errors inherent in such a procedure. The original lightcurve data is presented along with improved photometry. The exact phase location of the stellar spots is determined and the binary nature of the star is used to subtract the reflected light signal, estimated at more than 75 percent of the total light. An airglow correction is proposed, based on the elimination of a significant part of the thermal background. Since Arcturus emits predominantly in the optical part of the spectrum, a determination of the galactic dust emission is not needed, thus reducing the complexity of the calibration and also permitting its application to distant world or stellar samples.
The World View 4 image from the NRO’s Scanning Imaging Spectrometers air- and ground-based instruments on the DSN are described. A spectral calibration and absolute gain calibration using gold-silver-gold thin film resistor standards is presented. A sample of observations of Jupiter are also presented, showing the variations of the signal with time after a burst of electron density fluctuations. The updated DSN Routines Interface Commands to allow direct shooting of the data stream from the PDS to the DSN for processing are described.
The procedure for obtaining a uniform linearity test for the multichannel radiometer (MCR) is presented here, for investigating the uniformity of a radiometer's response to a uniform source, and is applicable irrespective of the number of channels and whether the MCR is single- or multi-channel. A set of narrow-band photometers calibrated and standardized using parabolic retroreflectors was obtained and used to test the MCR response for linearity of the detector signal over the test's range of calibration. Two channels of the MCR were then made to illuminate an illuminated screen, to test both operation and beam stability. Our results show that over a large part of range covered, the detectors can be treated as linear, with typical ratios between adjacent detector elements that are similar to the expected values for noise limited sensors. d2c66b5586