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Mini-TES mirror dust corrections Amy Trueba Knudson Mini-TES dust correction telecon 26 February 2007.

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Presentation on theme: "Mini-TES mirror dust corrections Amy Trueba Knudson Mini-TES dust correction telecon 26 February 2007."— Presentation transcript:

1 Mini-TES mirror dust corrections Amy Trueba Knudson Mini-TES dust correction telecon 26 February 2007

2 M. Smith whitepaper A sol 411 A sol 422

3 Mirror dust corrections 1.S. Ruff - Empirical retrieval of mirror dust spectral shape from pre and post-dusted external calibration target observations 2.A. D. Rogers - Empirical retrieval of mirror dust shapes (emission and transmission) through target transformation/factor analysis. Corrected spectra acquired through deconvolution with mineral library and reconstruction without dust endmembers. 3.M. Smith - Assumes known dust absorption shape (derived from TES data) and calculates Tau of mirror from upward and downward looking spectra throughout the mission

4 External Cal Target Correction S. Ruff  cor = [  o - (  ext-cal_  T1 -  ext-cal_predust + 1) + 1] Assumptions:  T1 (target - mirror  T) describes the necessary variables in mirror dust contribution Dust on External Cal Target has not changed since the dust cleaning/dusting event

5 FA/TT and Deconvolution A. D. Rogers FA/TT derived shapes –Mirror dust emission –Mirror dust transmission –Downwelling radiance Linear deconvolution with mineral library and dust shapes Reconstruct surface without dust and atm components A. D. Rogers whitepaper

6 Theoretical Correction M. Smith I corr (  )=[I cal (  ) - (1-e -T i (  ) ) x B(T inst,  )] / e -T i (  ) Assumes: Known spectral shape of the dust Known upward looking and downward looking spectral shape Dust is on one mirror and is emitting at the temperature of the optics Derived Instrument Tau Spirit τ i = 0 sol < 340 τ i = 0.05(sol − 340)/80 340 < sol < 420 τ i = 0.45 − 0.03(sol − 420)/250 420 < sol < 670 Opportunity τ i = 0 sol < 70 τ i = 0.075(sol − 70)/255 70 < sol < 325 τ i = 0.075 +0.205(sol −325)/75 325 < sol < 400 τ i = 0.28 + 0.47(sol − 400)/210 400 < sol < 610

7 El Dorado

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12 Coslada Madrid

13 Dust correction comparison External calibration target correction Works well at Spirit –Dust on external calibration target may remain thick enough for effectively constant emissivity since sol ~400. Does not work well for Opportunity –external cal target shows a lot of variation in Pancam data FATT/Deconvolution correction Does not seem to work well on Spirit –Need to investigate reasons for this, could be choices of library mineral endmembers Best current correction for Opportunity, gives reasonable results Theoretical correction Works well for Spirit –Can add a slope to derived emissivity - mirror temperature may not be accurate for the re-emitted radiation Only works well for dust in emission on Opportunity –Missing details of transmissive loss due to dust in the equation?


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