Method

The main menu contains buttons which allow a source region or background region to be defined and allow the two to be subtracted. Once a background or source region has been defined, they become the default; subtractions will use these regions until they are superceeded. This menu includes the following options:

OUTPUT

Allows an output file to be specified - by default all the results are written to the terminal.

MULTI

Once a background region has been defined - subtractions can be performed on a series of sources by selecting the MULTI option. This displays a further menu which has the choices NEWSRC and QUIT. The NEWSRC button must be pressed before each source is selected.

SUBTCT

Subtracts the current background data from the current source data, normalising for area.

Bckgnd

Defines the background region. This displays a further menu which allows the box shape to be selected.

Source

Defines the source region. This displays a further menu which allows the box shape to be selected.

SETBAD

Allows pixels within a polygon to be set bad.

ICL

Enables ICL temporarily so that a single command such as: IZOOM, ISCALE, $DIR etc... can be entered

• Bckgnd menu
• Multi menu
• Source menu