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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.

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Presentation on theme: "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."— Presentation transcript:

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2 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.

3 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)

4 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

5 SensitivitySensitivity Inflight sensitivity vs prediction from components HRCWFC

6 WFC Distortion Calibration 4 th order 2D polynomial fit matches observed distortion well - RMS residual 1.1 mas (.02 px) - peak deviation ~.2 px

7 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

8 WFC: Long wave halo Al metal layer reflects long- photons F814wF850LP

9 WFC: Long wave halo F775WF850LPFR1016N - 996 IR Encircled Energy Performance

10 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

11 Cats-Eye Nebula NGC 6543 (HRC) [OII] 3727 [OIII] 5007 H  Ramp filter

12 Coronagraph performance Target acquisition functions executed proposal second time with dithering to determine optimum location under each occulting spot

13 Coronagraph Dither Results

14 Coronagraph Performance

15 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.

16 Solar Blind Channel

17 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

18 HDF-N: i+ z & grism WFC - 2x i - 3x z orbits - “HDF overlay” Grism: 3 orbits

19 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)

20 HDF-N SN2002dc WFC 2x i + 3x z orbits, 3 grism orbits Galaxy & SN z=0.475 Identified from difference imaging with WFPC2 HDFN

21 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

22 SN2002ddSN2002dd Galaxy z=0.79 Identified from extracted spectra ! SnIa z=1.06

23 HDF-N SN2002dd Follow-up with DD proposal

24 Cool Image – A1689 Courtesy ACS Science Team

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26 Image Stability


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