Needs["ErrorBarPlots`"]

Read in the data from your local source

b=.

b = Import["http://physicsx.pr.erau.edu/MathematicaExamples/star2_richard.txt","Table"];

Length[b]

b[[100]]

Make a data structure      {time, distance}     and plot it.

error = Table[ErrorBar[b[[i,3]]],{i,1,Length[b]}];

flux = Table[{{b[[i,1]],b[[i,2]]},error[[i]]},{i,1,Length[b]}];

flux[[50]]

g1=ErrorListPlot[flux,PlotRange->{{6000,6200},{0.6,1.1}}]

g2=ErrorListPlot[flux,AxesLabel->TraditionalForm/@{"λ (Angstroms)","Flux (arb. units)"},BaseStyle->{FontFamily->"Times",FontSize->12},PlotRange->{{6000,6050},{0.6,1.1}}]