SGP/NIMFR/C1 - Intermittent noise, 500nm

Values of direct_normal_narrowband_filter2 (500 nm) were erratic at times, likely the 
result of a poor connection in the signal.  The erratic behavior is last seen on 20081101, 
before the connectors were cleaned.

Filter out obviously bad data. 20081029-20081101 are examples of bad data.

• optical depth for the Direct Narrowband Filter2(barnard_optical_depth_filter2)
• percentage of initial points used in final linear fit for the Direct Narrowband
  Filter2(barnard_good_fraction_filter2)
• rejection flag for Direct Narrowband Filter2(michalsky_badflag_filter2)
• number of points used in final linear fit for the Direct Narrowband Filter2(barnard_number_points_filter2)
• standard deviation around regression line for the Direct Narrowband Filter2(michalsky_standard_deviation_filter2)
• error in optical depth (slope) of final linear fit for the Direct Narrowband
  Filter2(barnard_error_slope_filter2)
• rejection flag for Direct Narrowband Filter2(barnard_badflag_filter2)
• optical depth for the Direct Narrowband Filter2(michalsky_optical_depth_filter2)
• solar constant corrected for solar distance for the Direct Narrowband Filter2(michalsky_solar_constant_sdist_filter2)
• solar constant corrected for solar distance for the Direct Narrowband Filter2(barnard_solar_constant_sdist_filter2)
• Langley regression Io, Michalsky, Direct Narrowband Filter2(michalsky_solar_constant_filter2)
• number of points used in final linear fit for the Direct Narrowband Filter2(michalsky_number_points_filter2)
• error in final linear fit for the Direct Narrowband Filter2(barnard_error_fit_filter2)
• percentage of initial points used in final linear fit for the Direct Narrowband
  Filter2(michalsky_good_fraction_filter2)

• Direct normal narrowband irradiance, filter 2(direct_normal_narrowband_filter2_raw)
• Direct normal narrowband irradiance, filter 2, offset corrected(direct_normal_narrowband_filter2)

• Narrowband Direct Horizontal Irradiance, Filter 2, cosine corrected(direct_horizontal_narrowband_filter2)
• Direct normal narrowband irradiance, filter 2, offset corrected(direct_normal_narrowband_filter2)

• log(irradiance) for the Direct Narrowband Filter2, Barnard(barnard_lnI_filter2)
• rejected points for the final fit for the Direct Narrowband Filter2(barnard_rejected_filter2)
• rejected points for the final fit for the Direct Narrowband Filter2(michalsky_rejected_filter2)
• log(irradiance) for the Direct Narrowband Filter2, Michalsky(michalsky_lnI_filter2)