###########################################################################
225 gigahertz tau fits- done by Jonathan Bird, CALTECH
Updated: 2003-12-11

Files contained in this directory:
tau225.README-		This file.
YYMMDD.ps-	plot of that day's 225 gigahertz tau data. The fit line is plotted in red.
		Residuals of the fit appear below each plot.
tau225_all.fit-	ASCII text file containing the functions for each fit.
shartau.tar-	Tarball of sharctau source, used in conjunction with these fits and explained below.

###Model###
These are least square polynomial fits of t, where t is simply the UT time expressed as fraction of a day. This format was chosen to mirror similar fits performed by Berndt for the JCMT. For the 225 Ghz fits, the data is weighted by 1/(sigma)^2. 


###The format of tau225_all.fit is as follows###

UTdate t_1 t_2 order coefficients

where:
The UTdate is in YYYYMMDD.
t_1 is time at which the fit becomes valid.
t_2 is time at which the fit becomes invalid.
order is simply the order of the fit.
The coefficients then follow, starting with the constant term. Each coefficient is separated by a space.

Note: t_1 and t_2 are in fraction of a day form. t_1 to t_2 is obviously the range of time over which the fit is valid.

###Sharctau###
Sharctau, a C program written by Colin Borys, takes as input a scan, reads that scan's header, extracts the date and time the scan was taken, parses through the tau350.fitall file, finds the correct function and plugs in the appropriate time, returning the best fit tau. 


###Planed updates###
1) Still unhappy with the fits for the following days:
	#List to come shortly...

	I will get these fixed as soon as possible. I am sure there are others that can be improved.


###Comments?###
Please email bird@submm.caltech.edu if you have any comments or suggestions. Any input on fits that you think need improvement (and not specifically mentioned above) would be greatly appreciated.