GSC2 @ ESO:Applications to the ESO Imaging Survey and to the VLT

R.Mignani (ESO)

7th GSC2 Meeting

2001

ESO Imaging Survey (www.eso.org/eis)• The ESO Imaging Survey (EIS) is a pilot project in

preparation for VST (2003) and VISTA (2004)

ESO Imaging Survey• EIS carried on with WFI@2.2m (34x33 arcmin 8 chips

mosaic CCD)• GSC2 is now used in the EIS pipeline for astrometric

calibration of the survey fields• The Deep Public Survey (DPS) (started fall ‘99) covers 3

(0.5x2 deg) patches in UBVRI + JKs, including Chandra Deep Field South

• EIS CDFS observations relased early this year (Vandame et al. 2001 A&A- accepted; Arnouts et al. 2001 A&A in press)- test release of GSC2.1 used (<0.1” rms)- data will be rereleased asap with GSC2.2 astrometry

• The Pre-FLAMES Survey (PFS) covers 160 (0.5x0.5 deg) fields in BVI - GCs, OCs, LMC, SMC, GB ... targets for the SV of FLAMES@KUEYEN• The GOODS/ESO observations of the CDFS tbd with WFI@2.2m, ISAAC@Antu

GOODS/ESO coverage

EIS coverage

NGC1904

FLAMES@KUEYEN• FLAMES is a Fiber system feeding GIRAFFE and UVES MOS spectrographs @VLT/KUEYEN (Commissioning end

of 2001)• GIRAFFE in MEDUSA mode is fed by 130 fibers (1.2” diam)• Automatic ACQ • Very stringent requirements on the astrometry (< 0.2”)• Challenge for the GSC2• First data released so far:• 4 OCs: Berkeley 20, NGC 2477, NGC2506, M67• 2 SMC Fields: NGC330,NGC346• Momany et al 2001 A&A-in press

USNOA2.0 vs GSC2.2Test computed wrt the M67 field

RA,DEC residuals vs RA,DEC

RA,DEC residuals vs mag

USNOA2.0&GSC2.2 vs RefAstrometry compared vs Reference astrometry of M67 field (Girard et al. 1989 AJ 98, 227)

Landolt vs GSC2• Visual inspections on the DSS have shown that Landolt

stars are off from the nominal positions (Landolt 1992 AJ 104,340)

• In some cases, differences up to few arcmin have been found

• Unknown PMs (to be measured)• Errors in the original Astrometry• Pbs for automatic recognition of standards and photom pipelines• Reassessment of Landolt coo in the GSC2 system• Interactive ID interface set up with SKYCAT• Possible variables found• The revised Landolt cat being published

Conclusions• ESO is waiting for 100% sky coverage before using

routinely GSC2 for telescope operations • EIS is GSC2 “best customer” with GSC2 used in ALL EIS Surveys• GSC2 accuracy well within the requirements• GSC2 is valuable support for FLAMES users• GSC2 used to set a new astrometric standard for Landolt

stars --> important for pipeline photometric calibrations ... not only EIS but also VLT