RAS/HOMS Calibration Plan : BATC (Feb-Mar 2001)

AUTHORS : A. Martel and G. Hartig

GOAL :

The goal of this campaign is to obtain a potentially final set of all calibration data for the HRC Build 1 and WFC Build 4 flight detectors with RAS/HOMS (Refractive Aberrated Simulator/Hubble Opto-Mechanical Simulator), which provides an external, OTA-like illumination above its refractive cutoff wavelength of ~3500 Ang. A host of activities will be undertaken to acquire pre-launch data that would be prohibitive or impossible to obtain on-orbit or at GSFC. The SBC has been fully calibrated in the first thermal vacuum campaign (TV1) and so is not considered in this campaign.

LOCATION AND DATE : BATC : Feb 20 - Mar 2, 2001

INSTRUMENT CONFIGURATION :

ACS is fully integrated and all flight detectors are in final alignment in RAS/HOMS in ambient environment. The lab chillers are attached to the ASCS I/F plate. It is assumed that at the start of the calibration program, the instrument is in its flight configuration and has been fully verified. No adjustments, alignments, or other modifications to hardware or software are expected once this program commences. If such changes are made, some aspects of the calibration may be rendered invalid. The clean room is light-tight. By default, all the data will be acquired with MEB 1, although if time permits, comparison data will also be obtained with MEB 2. The default gain settings are 1 e-/DN for the WFC and 2 e-/DN for the HRC, with a bias offset of 3 for both detectors. The WFC will be read-out with all four amplifiers (ABCD) and the HRC with amp C, the least noisy of its four amps. A brief description of the chip formats is available.

APPARATUS :

The different light stimuli and optical elements used in RAS/HOMS for this campaign are described in detail in Calibration Facilities, Test Apparatuses, and Stimuli.

CALIBRATION ACTIVITIES :

The calibration activities for this campaign are divided into several items, listed in the following table. The estimated execution time for each activity is tabulated, as well as the command mode, either in real time (RT) or by SMS.

Note :

• FF : Flat field.
• PP : The Mylar transmissive diffuser is placed at the location of the pupil plane.
• FP : The Ronchi ruling, the inverse field mask, or the pinhole array are placed at the RAS focal plane.
• T2, T4 : Internal tungsten lamps for the WFC (T2) and HRC (T4).
• The number of hours is the minimum execution time for each item simply based on the number of exposures and chip read-out times. Overhead for test exposures, changes in instrumental setup, contingencies, etc..., will likely be significant.
• Since the illumination for the "Gain Measurements" is entirely internal, it is preferable to schedule its execution outside the RAS/HOMS campaign.

MISCELLANEOUS :

• Complete list of spreadsheets and IDL procedures for this campaign