Specifies the degree to which arc line features are required to exceed the continuum intensity before they are considered as valid features.
The default value of 1.25 is deliberately low to allow the automatic line-identifier access to very faint features. This parameter should not need adjusting unless the arc spectrum has a difficult continuum or other special problems associated with it. The line identification task provides interactive control over the minimum intensity for 'fitted' features via its (T)hreshold option.
The default value is 1.25.
Martin Clayton