IOTA Technical Documentation

What follows is a series of technical articles I wrote while I was developing the data acquisition and control software for the IOTA (Infrared and Optical Telescope Array) project at the Smithsonian Astrophysical Observatory on Mount Hopkins near Amado, Arizona. I wrote these documents for my own reference, so they are sketchy and incomplete, but sometimes useful nonetheless. This stuff is largely out of date due to a recent upgrade to a VxWorks based system that I had nothing to do with.

• Baseline is a description of how to calculate the baseline vector between two telescopes using the delay line positions measured in a series of observations.
• Catchup is a description of how to move an axis (i.e. telescope axis or delay line) so that it will rendez-vous with a moving target position without overshooting.
• Photons is a calculation of the number of photons per second in the photometric V band that you would expect from a magnitude 0 star, and a description of photometric measurements at IOTA that show that about 99% of the light is being lost.
• Pointing is a description of the pointing model for the siderostats.
• Search is a description of how to execute a circular spiral search for a star.