Tools, Analysis  

Wolfram Knowledge Base, including function graphing and analysis.
Wolfram math reference, dictionary style.
Integrator on Wolfram.
Chi-square probability and critical values applet.
Sage open source substitute for Mathematica.
NIST data gateway.
Ferland et al. atomic line list.
Handbook of Space Astronomy and Astrophysics
LaTeX wikibooks cribsheet.
Cribsheet table for html code for Greek Letters and Symbols.
English usage.
Toroidal, X-ray reprocessor model for Compton-thick and Compton-thin AGN.
Suzaku data anlaysis page on HEASARC.
Suzaku CALDB page on HEASARC.
XMM-Newton data analysis page.
XMM-Newton calibration page.
Heasoft latest information and downloads on HEASARC.
HEASARC list of latest versions of a collection of astronomy software.
XSTAR manual online.
XSPEC pdf manual.