Phase 2 Proposal Instructions for Cycle 10

9.4 WFPC2 Aperture Coordinate System

---

Figure 9.1: WFPC2 Aperture Coordinate System

 

 

Coordinate system is onto the sky for the POSition TARGet Special Requirement. The short lines indicate the blooming directions of the CCDs. Units are seconds of arc. See POSition TARGet <X-value>, <Y-value> for details.

Note that the POS TARG XÐ and YÐaxes are not the same as the U2Ð and U3Ðaxes, and that POS TARG axes are associated with each aperture selected (i.e., there is a POS TARG coordinate frame centered on each aperture).