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Hubble Space Telescope
Phase I: 12086

COS Cycle-17 Calibration Phase-1 Template

Last Revised:			Date
Proposal ID:			(e.g. 9026)
Title: Generation of 1-D Fixed Pattern Templates
PI:	
Co-I(s):	

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# Orbit estimates are TOTAL for all of cycle-17; assume 72 weeks) 

Total Prime Orbits:             11
External Parallel Orbits:       0
Internals or no-impact orbits:  0
Comments on orbit estimate:     From previous, similar observations


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# This section should be written with a GO audience in mind -- use 
# Calibration plans in WFPC-2 handbook as a guide.

Purpose:  
Obtain the data needed to construct 1-D fixed pattern templates to correct 
the grid wire shadows and detector features in COS medium dispersion spectra. 

Description:   
Tests have shown that application of a 1-D fixed pattern template to a COS 
spectrum can reduce the fixed pattern noise in G130M or G160M spectra to an 
equivalent S/N of about 30/1.  For this to be occur, the template must be 
derived from data for the same grating and nearly the same central wavelength 
as the observation.  This is because each grating has a different cross 
dispersion profile, and different central wavelengths fall at different 
cross dispersion detector locations.  As a result, spectra obtained at each 
grating and central wavelength setting are derived from different regions of 
the detectors -- each with their own, unique detector features and grid wire 
shadows.  

The high S/N spectra obtained in Program 11494 produced reliable templates for 
one G160M (CENWAVE=1600) and one G130M (CENWAVE=1309) setting.  These settings 
fall at the mid-points of the cross dispersion pixel ranges covered by the 
different CENWAVE settings for each grating.  To span all of the cross
dispersion positions encompassed by the nominal grating positions (about 3 
pixels for the FUVA and 2.5 for FUVB), we must obtain data for the extreme 
settings: CENWAVE=1577 and 1623 for the G160M, and CENWAVE = 1291 and 1327 
for the G130M.  Together with the existing data, the new observations will 
provide a large enough set of 1-D templates to insure that there wiil be a 
template within half of a cross dispersion pixel of observations at the 
nominal CENWAVE settings.  In this way, errors introduced by interpolating 
the available templates to the observed cross dispersion location will be 
minimal.  



Accuracy:                       2%
Comments on Accuracy:           Poisson
Products:          
1-D flat filed templates to correct G130M and G160M spectra for grid wires 
and detector features.  

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# Link to Cycle 17 Science
# Use the GO + GTO Phase 1 exposure  listing and derived statistics
# posted on WWW.

Fraction of science programs supported by this calibration:     100%

List categories of science which can't be executed until after this proposal:
why:
All G130M or G160M data contain grid wire shadows and detector features 
which need to be removed.  

List categories of science which are best performed contemporaneous with 
this proposal:
All

why:
The proposed observation will affect all quantitative measurements.

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# THE REST OF THIS FORM IS FOR INTERNAL USE
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Observation summary:

# Target information (copy for each target)

Target Name.............................: GD50
RA......................................:		
Dec.....................................:		
Flux (and units)........................:	
Visibility window (if known or relevant):
Comment on choice of target:

Target Name.............................: WD0947+857
RA......................................:		
Dec.....................................:		
Flux (and units)........................:	
Visibility window (if known or relevant):
Comment on choice of target:

# Exposure list plan at the Phase I level. Be as complete as reasonable. 
# If possible information should be complete enough to allow easy 
# submission of a Phase 2 from this form. However, if you have to leave
# some of the fields blank below, or want to provide the information
# in another format, that is acceptable. (Make sure you do the BOP checking
# though, as this is a phase-1 issue.)

Table of exposures (copy for each exposure as appropriate/desired):

Target or lamp..........................: WD 0947+857
Type of Acquisition.....................: ACQ-IMAGE
Detector for observation................: FUV
Operating mode .........................: TIMETAG
Spectral Element........................: G130M
Aperture................................: PSA
Central Wavelength......................: 1291, 1327
Exposure Time...........................: 2500s each, fp-pos=1,2,3,4
Number of Iterations ...................: e.g. 1
BOP Predicted Local Count Rate for MAMA.:
BOP Predicted Global Count Rate for MAMA:
ETC PID IDs for Count Rates.............: 
Special Requirements or options.........: (e.g. GAIN=4; LOW-SKY)
Comments: (e.g. if monitoring, specify frequency) 

Target or lamp..........................: GD50
Type of Acquisition.....................: ACQ-IMAGE
Detector for observation................: FUV
Operating mode .........................: TIMETAG
Spectral Element........................: G160M
Aperture................................: PSA
Central Wavelength......................: 1577, 1623
Exposure Time...........................: 2500s each, fp-pos=1,2,3,4
Number of Iterations ...................: e.g. 1
BOP Predicted Local Count Rate for MAMA.: Exceeds global FUVB count rate by 19%
BOP Predicted Global Count Rate for MAMA:
ETC PID IDs for Count Rates.............: 
Special Requirements or options.........: (e.g. GAIN=4; LOW-SKY)
Comments: Target exceeds the global FUVB count rate by 19% and must be 
approved.