Bilinear/Spline how to use them?

[Firefly]

In ISIS's setting Tab, Interpolator type has Bilinear/Spline. I want to know what their difference is? and at what kind of situation shall I use Bilinear? what situation is better to use Spline?

Thanks.

Dong .Li

[Christian Buil]

Spline interpolator give sharpen spectra (less low pass filter effect during processing). But be carrefull if your spectrum show very contrasted features (planerary nebula spectrum for example) : spline interpolation can produce artifact at the base of spectral lines. I recommand, specially for LISA users, to select the linear interpollator for all standard work.

Christian B

[Firefly]

Thank you ! Mr.Buil.

Dong .Li