THE ISO POINTING PERFORMANCE

摘要

The standard ISO observing mode was a 3-axis stabilised pointing at a selected astronomical target, allowing observations for a period up to several hours. The ISO pointing performance was found to be better than expected at the time of satellite commissioning. It appeared during the first months of the mission that further improvement was possible, which would benefit those scientific instruments using smaller apertures, in particular the SWS. Thanks to the good collaboration of motivated spacecraft and operation teams, co-located at the Ground Station, a new method for minimisation of residual errors was developed and successfully applied after a year of operations. Subsequent improvements in the pointing system were achieved also after the mission and applied in the Offline Processing Pipeline, reaching an absolute pointing error of ≈1.4", which is almost an order of magnitude better than the specifications.