A spatial and spectral information of the diffuse galactic light emission
is taken from literature:
Lillie and Witt (1976).
Gondhalekar and Wilson, A&A,1975,38,329
Mattila, A&A,1980,39,53
Bahcall & Soneira ApJS, 1984, 55, 67
Leinert et al. (A&AS, 1998, 127, 1)
The spatial distribution of the DGL is contained in the DGL_MAP extension.
The galactic coordinate system is used.
The spectrum is compiled from literature and written into the extension
DGL_SPEC. The intensity of the spectrum is scaled to the reference intensity.
The photon rate are estimated by folding the DGL spectrum with OSIM.
The binary table DGL_CTS lists the expected photon rates for the different
filters at the reference intensity.