Bruno Altieri -- SCI-SDX
XMM
EPIC astrometry update
EPIC CAL/OPS meeting
Vilspa, 23-24 March 2003
B. Altieri
XMM-Newton
2
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.
XMM-Newton
3
Bruno Altieri -- SCI-SDX
XMM-Newton
4
Bruno Altieri -- SCI-SDX
XMM-Newton
5
Bruno Altieri -- SCI-SDX
XMM-Newton
6
Bruno Altieri -- SCI-SDX
Systematic shift in MOS1 CCD6
MOS1
MOS2
XMM-Newton
7
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
XMM-Newton
8
Bruno Altieri -- SCI-SDX
No residuals with old BORESIGHT CCF
XMM-Newton
9
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