# Flat correction (dialog)

The “Flat correction” dialog is used to select a flat frame during the calibration of the source files. The flat-frame calibration is used in the standard and the advanced calibration scheme.

## Activating the dialog

The dialog can be activated:

1. from the main menu: Reduce ‣ Flat correction.

2. from the main toolbar:

## File browsing

The dialog for selecting a flat frame

The button “Type a file name” (1) shows and hides the “Location” text box. The keyboard shortcut Ctrl+L key combination does the same action.

In the “Location” text box (2) you can type a path to a file. If you don’t type any path, the name of the selected file will be displayed. You can also type the first letters of the name: it will be auto-completed and a list of file names beginning with these letters will be displayed.

(3) The path to the current folder is displayed. You can navigate along this path by clicking on an element.

(4) Here, you can access to your main folders and to your store devices.

(5) Here, you can add bookmarks to folders, by using the “Add” or the “Add to Bookmarks” option you get by right-clicking a folder in the central panel, and also remove them.

The contents of the selected folder is displayed here (6). Change your current folder by double left clicking on a folder in this panel. Select a file with a single left click. You can start the operation by clicking on the Execute button or by a double left click on a file. Right-clicking a folder name opens a context menu.

If the selected file is a file recognized by the C-Munipack, the preview and short info is displayed in the right part of the dialog (7). Double click on the preview to show a larger preview in a separate dialog.

(8) By clicking the Add button, you add the selected folder to bookmarks.

By clicking the Remove, you remove the selected bookmark from the list.

(9) It is possible to apply the operation on all source files in the project or on the files that are currently selected in the table of input files.

## Applying the flat correction

Click the “Execute” button (10) to start the operation. The flat correction is applied to a working copy of source files. The working copy is replaced by corrected frames.

- A working copy of source frame must be made before the flat correction.

- The bias and the dark correction must be applied before the flat correction, if necessary.

- The flat correction can be applied to each frame only once.

- The flat correction must be applied before the photometry.

If you make a mistake, you can revoke the step by making a fresh copy of source frames by means of the “Fetch/convert files” function.

See also

Main window, Master flat frame (dialog)