  The software package aXe provides comprehensive spectral extraction
facilities for all the slitless modes of the ACS, covering the Wide Field
Channel (WFC) grism, the High Resolution Channel (HRC) grism and prism and the
Solar Blind Channel (SBC) prisms. The latest developments to the package apply
to all ACS slitless modes leading to improved spectral extraction. Many
thousands of spectra may be present on a single deep ACS WFC G800L image such
that overlap of spectra is a significant nuisance. Two methods of estimating
the contamination of any given spectrum by its near neighbours have been
developed: one is based on the catalogue of objects on the direct image;
another uses the flux information on multi-filter direct images. An improvement
to the extracted spectra can also result from weighted extraction and the Horne
optimal extraction algorithm has been implemented in aXe. A demonstrated
improvement in signal-to-noise can be achieved. These new features are
available in aXe-1.5 with the STSDAS 3.4 release.
