## Notes on ACIS-S SIM-Z exclusion region of -8 to -11 mm

 ```***---------------------------------------------------------------*** *** Basic numbers *** ***---------------------------------------------------------------*** SIM TSC translation scale size (meters/step) from ODB characteristics ODB_TSC_STEPS = 2.51432D-06 Exact : 2.51432e-3 mm/step => 9.8989e-5 inches/step Roughly: ~400 steps/mm => ~10000 steps/inch Effective fid light distance from ACA = 10065 mm => 20.49 arcsec/mm (ACA angular displacement / mm SIM translation) ***---------------------------------------------------------------*** *** Exclusion zone *** ***---------------------------------------------------------------*** Find recent fid positions based on obsid 5370 (JUL1805 load) Fid 4 ang_y[deg] = 0.59848 ang_z[deg] = 0.04931 = 177.52 arcsec Fid 5 ang_y[deg] = -0.50331 ang_z[deg] = 0.04753 = 171.10 arcsec At position of fid 4, quadrant boundary is at Zag = -27 At position of fid 5, quadrant boundary is at Zag = -22 Fid 4 crosses boundary at (-22 - 171) / 20.49 = -9.4 mm Fid 5 crosses boundary at (-27 - 177) / 20.49 = -10.0 mm A pad of 1mm => ~4 ACA pixels ***---------------------------------------------------------------*** *** ACIS review checks *** ***---------------------------------------------------------------*** From Joe DePasquale: Our ACIS review script checks the Z-sim offset and reports an error if it is between -8.1 and 11.0 mm while the FP is at ACIS-S: if (\$delta_zsim < -8.1 && \$delta_zsim > -11.0 && \$SI2 =~ "ACIS-S") { printf OUT "\n>>>ERROR: THERE IS A SIM TRANSLATION OF %5.2f mm FOR THIS OBSERVATION.\n",\$delta_zsim; print OUT ">>> POSSIBLE FID LIGHT PROBLEM -- Z-SIM IN BLOCKED-OUT REGION.\n\n"; ``` Aspect Information main page Comments or questions: Aspect Help Last modified:10/13/05