90 likes | 192 Views
EPIC astrometry update. EPIC CAL/OPS meeting Vilspa, 23-24 March 2003 B. Altieri. MOS metrology & astrometry. Goal: improve MOS relative astrometry MOS metrology in LINCOORD CCF : relative CCD offsets How : cross-correlate EPIC source list with 2MASS (NIR)
E N D
EPIC astrometry update EPIC CAL/OPS meeting Vilspa, 23-24 March 2003 B. Altieri Bruno Altieri -- SCI-SDX
MOS metrology & astrometry • Goal: improve MOS relative astrometry • MOS metrology in LINCOORD CCF : relative CCD offsets • How : cross-correlate EPIC source list with 2MASS (NIR) • 2MASS astrometric accuracy < 0.2” • Tune new BORESIGHT CCF (v17) for possible systematics in absolute astrometry and relative astrometry between EPICs. Bruno Altieri -- SCI-SDX
Systematic shift in MOS1 CCD6 MOS1 MOS2 Bruno Altieri -- SCI-SDX
Hint of systemic astrometry residuals • Global astrometry shift tends to be in same direction in S/C frame • But statistics is poor (nobs=14) • Hint of offset between MOS1 and MOS2 • But correlation is not very good thermal bending effect ? • or reaching limit of measurement accuracy Bruno Altieri -- SCI-SDX
No residuals with old BORESIGHT CCF Bruno Altieri -- SCI-SDX
Astrometry: an old job ! Nebra sky disc: “The oldest concrete representation of the stars in the world” 2002, Nebra, Germany, 3600 yr old Bruno Altieri -- SCI-SDX