The Main Program Window
When you first load a file fitlc will make an initial rough sweep to populate the period-chi phase space for each template. This can take a while, especially if you are fitting multiple filters or have a generally slow computer. It checks from the period range of .2 to 1.0 days at evenly spaced intervals of .01 days. After it finishes this, it selects the template with the period-template combination with the lowest chi-sql residuals. It then displays this fit in the main program screen, updates the text inputs on the left side of the screen with the appropriate values, plots the period vs chi plot on the top of the screen, and plots out the best fit for each template in the small boxes on the right. It automatically sorts the templates on the right according to their minimum chi values, so technically template 1 should always be the best fitting template and template 8 the worst. There's a lot you can do from the main program window. Below is a picture of a just loaded light curve (click it for the full size version). In fact, this is the file I included as an example on the loading files page.
The Left Bar
On the left is a series of text columns that display the parameters for the fit currently displayed in the main window. You can adjust any of these parameters by hand, and fix any of them by clicking the 'fix' checkbox next to it. If you decide to fix a parameter, you must refit the curve by going to the 'Fitting' menu and clicking 'Re-Fit' There's no point in adjusting parameters if you don't fix them. Any changes you make that aren't fixed will simply be erased when you re-fit the light curves.
The Right Bar
On the right are the best fitted curves for each template. If you click on the plot for a template on the right, the best fit for that template will be displayed in the main plotting window, and the period-chisq plot for that template will be displayed in the center-top. The templates are plotted in order of increasing chi, so the top left template is always the best fitting template, and the bottom right template is the worst fitting.
Display Options
Directly below the main plot window is a series of three checkboxes. Clicking these will change what is displayed in the main plot window. By default, 'Fitted' is selected. This option simply displays the best fitting template. If you select 'Best Fits', it will display the best four fitting plots. Finally, 'Observed' will display the raw light curve, unchanged by any fit parameters. You can change the displayed xrange for the observed plot by specifiying the minday and maxday settings when you load your file.
Chi-sq Plot/Slider
Below the period vs chi-sq plot is a slider. Adjust this slider to quickly adjust the period of the fit. Fitlc will then refit the currently selected template using the selected period, along with any other settings you might have fixed. To provide results quickly it only re-fits the currently selected template. Because the slider only adjusts the currently displayed template, the results are not stored internally. So, before you do anything else (such as using auto-fit, saving, changing templates, etc..) you must use the Re-fit option in the menu bar to actually apply the new period, otherwise your selected period will be lost.
The Main Plot
You can interact with the main plot when you are displaying the best fit or the observed light curve. When either of these two plots are displayed, you can click on a data point to "select" it. A selected point is assigned a random color to distinguish it from the other points. This color is kept consistent throughout all plots in the fitlc screen, allowing you to easily tell where a point in the observed light curve is transformed into the fitted light curve, and to see where it is located in all templates as well. You can select as many points as you want, and if you click a point again, it will be deselected.