TUI supports the following offsets: . Object Arc offset by a given amount on the sky (i.e. along the arc of a great circle). ... Arc offsets are useful for moving a different portion of your object or a different nearby object onto the boresight . ... Object Arc XY this is identical to an Object offset except that it has been rotated to align along the instrument x-y axes. ... This is just like the Calibration XY offset, except that it is typically cleared when you slew to a new object. ...

. " The Arecibo Observatory is sponsored by the National Science Foundation. Any opinions, findings and conclusions or recommendations . expressed in this publication are those of the author(s) and do not necessarily reflect the views of the National Science Foundation."

... Near Infrared Camera and Multi-Object Spectrometer Instrument Handbook for Cycle 17 > Chapter 6: NICMOS Apertures and Orientation > 6.1 NICMOS Aperture Definitions . ... Each HST Science Instrument requires its own local coordinate system and apertures to support both target acquisition and small angle maneuvers (SAMs). ... Each NICMOS camera has two primary apertures. One is positioned at the geometric center of the detector and the other at an optimal position close to the center. ...

The Optical Solar Sensor (OSD) has been designed to determine the direction towards the center of the Sun's visible disc. The direction to the Sun is computed in the instrument coordinate system relative to the pixels' position on the linear CCDs illuminated with the light passed through the incoming coding mask. The OSD coding mask has three groups of slits with three slits in each group. This mask configuration provides for reliability increase as well as for the required accuracy. ...