I began the astroutils site in ~2010 when I was a graduate student at OSU. For 15 years after I graduated, OSU graciously continued to host them. Unfortunately, they are no longer able to do so. If you know of someone who might be willing to host them (they require a PHP script that calls out to the shell to run an IDL code on the server side), please contact me at jason.eastman@cfa.harvard.edu.

Meanwhile, here are some alternatives you might find useful:

• BJD calculator:
  https://arbiter.nextastro.org/toolkit/bjd-converter
• Limb darkening coefficients:
  https://exoctk.stsci.edu/limb_darkening
• EXOFAST modeling:
  https://exoplanetarchive.ipac.caltech.edu/cgi-bin/ExoFAST/nph-exofast
• Ephemeris Calculator:
  https://exoplanetarchive.ipac.caltech.edu/cgi-bin/TransitView/nph-visibletbls?dataset=transits
• Barycentric Velocity Calculator:
  https://pypi.org/project/barycorrpy/ (python package) https://github.com/jdeast/EXOFASTv2/tree/master/barycorr (IDL package)