LLiST - IOTA's new star tracker camera

On March 10, 2004, around 1:30am MST, the control loop on the three telescopes of IOTA was closed for the first time with LLiST, the new star tracker camera.

Nat Carleton and Peter Schuller operated the instrument on site, while Pete Schloerb (see monitor) worked on the software remotely.

A screen snapshot of the control software. Note the parameters used, mainly "Threshold" and "IntTime" for the star tracker.

A modified version of the current control software was used, dubbed ICS 3.2-LL and invoked by launching "vxworks-start-LL" instead of "vxworks-start" at the right place (see computer startup notes). The shortes possible integration time in closed loop operation was 2ms, so that the control system was still in sync with the camera. The readout time of LLiST alone lies under 1ms in the mode used. This mode bins 4x4 pixels into one "super pixel" and therefore corresponds to "coarse mode". It is currently the only mode available with LLiST.

Some technical details

(will gradually be updated)

• Star tracker camera assembled at MIT's Lincoln Laboratory.
  • Thermoelectric cooler (TEC) by FerroTec Inc.:
    part 6300/017/040 (17-couple, 4-ampere, single-stage)
  • Thermistor (on cooler) by Thermometrics Inc.:
    part HM35NF103J (10 000Ohm @ 25°C), material type F;
  • TEC controller by New England Photoconductor (NEP):
    model TC2-030, 2.5A max. TEC output current
• To prevent light leakage from the Short Delay Line metrology laser to the star tracker, which could confuse the tracker's performance, a filter was installed in front of the camera. The filter (Rugate notch filter by Edmund Optics Inc.) has a transmission rejection band with a central wavelength of 632.8nm and a FWHM of 31.6nm.
• First and preliminary test results

Last update: PASch, 2005-01-25