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Published byAdelia Willis Modified over 9 years ago
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Image Stability ACS SMOV image stability test (prop 9017) went from a cold soak (anti-solar pointing) for 8 orbits to a hot attitude (including off-nominal roll) –Nominal jitter (typically about 3 mas RMS and 10 mas peak-to-peak) –Smooth drift at rates up to about 6 mas/hr in both the HRC and WFC (same direction). –Drift may be due to FGS's or to rigid body movement of the ACS wrt the OTA –Similar to image drift rates for other SIs.
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Calibration – Flat Fields L-flat for the F555W filter, the plot is a 4th order least-squares fit to the stellar photometry. –~10% gradient from upper left to lower right –(Mack, van der Marel, Bohlin, Blakeslee, Cox)
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Flat field – Sanity Checks Ratio of the F555W photometry in the CRJ to the DRZ image, corrected for distortion. –White is 1.10 and black is 0.93. Pixel Map from Geometric distortion – ratio produces 1% residual
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SensitivitySensitivity Inflight sensitivity vs prediction from components HRCWFC
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WFC Distortion Calibration 4 th order 2D polynomial fit matches observed distortion well - RMS residual 1.1 mas (.02 px) - peak deviation ~.2 px
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WFC CCD Amplifier Cross-talk Low-level “ghosts” of extended objects mirrored in alternate quadrants Slight “droop” (fractional e-) in bias level of all 3 alternate amps Ghosts do not appear to be proportional to target signal Hard (2 e - ) stretch of WFC UGC10214 image
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WFC: Long wave halo Al metal layer reflects long- photons F814wF850LP
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WFC: Long wave halo F775WF850LPFR1016N - 996 IR Encircled Energy Performance
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Optical “Ghosts” Two ghost features have been identified with >0.1% of target energy: WFC CCD to window reflection produces pairs of elliptical ghosts with ~ 0.2% integrated energy F660N [NII] filter produces halos with ~2% of integrated energy due to reflection between its surfaces
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Cats-Eye Nebula NGC 6543 (HRC) [OII] 3727 [OIII] 5007 H Ramp filter
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Coronagraph performance Target acquisition functions executed proposal second time with dithering to determine optimum location under each occulting spot
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Coronagraph Dither Results
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Coronagraph Performance
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SBC – First Light Image Globular star cluster NGC6681. This cluster, with [Fe/H] = -1.5, is rich in Blue Horizontal Branch stars.The image combines first light data taken with three filters F125LP, F150LP, and F165LP.
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Solar Blind Channel
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CALACSCALACS First generation updates to CALACS & PyDrizzle are complete, software is frozen for distribution in next STSDAS Includes ST-ECF AXE software for grism/prism Mosaic generated from 18 images of 47 Tuc
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HDF-N: i+ z & grism WFC - 2x i - 3x z orbits - “HDF overlay” Grism: 3 orbits
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HDF-N ACS Grism examples Emission-line galaxy with continuum and knots - [OIII] 5007 and H 6563 Redshift z = 0.319 F814 AB = 22.5 (WFC 2x i + 3x z orbits, 3 grism orbits)
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HDF-N SN2002dc WFC 2x i + 3x z orbits, 3 grism orbits Galaxy & SN z=0.475 Identified from difference imaging with WFPC2 HDFN
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HDF-N SN2002dc Galaxy and SN at z=0.48 SN mag. is 22.7 (i) Type I (probably Ia) Galaxy & SN z=0.475
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SN2002ddSN2002dd Galaxy z=0.79 Identified from extracted spectra ! SnIa z=1.06
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HDF-N SN2002dd Follow-up with DD proposal
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Cool Image – A1689 Courtesy ACS Science Team
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Image Stability
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