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Space Telescope Imaging Spectrograph
Phase I: STIS CCD Spectroscopic Flat-field Monitor

STIS Cycle-18 Calibration Phase-1 Template

Last Revised: 10/08/2010			
Proposal ID:  12405		
Title:	 STIS CCD Spectroscopic Flat-field Monitor
PI: 	 Elena Mason	
Co-I(s): Charles Proffitt 	

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# Orbit estimates are TOTAL for all of cycle-10; assume 72 weeks) 

Total Prime Orbits:             0
External Parallel Orbits:       0
Internals or no-impact orbits:  37
Comments on orbit estimate:     
_ 9 orbits for  G430M+50CCD spread across the cycle:  one orbit every 41
days;
_ 10  orbits  for G430M+52x2  possibly  to  be  executed within  a  same
annealing period and early in the  cycle (beginning Dec 2010 - end Jan
2011);
_ 5 orbits for G430L+50CCD of which the first 3 orbit should be executed
early  in the  cycle  (beginning Dec  2010  - end  Jan  2011) and  the
remaining 2  are "spread"  across the period  (separated by  about 120
days each other);
_ 10  orbits  for G430L+52x2  possibly  to  be  executed within  a  same
annealing period and  early in the cycle (beginning Dec  2010 - end of
Feb 2011);
_ 3 orbits for  G750L+50CCD to be executed during the  first part of the
cycle (beginning of Dec 2010 - mid Feb 2011).


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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:  Determine the  pixel  to pixel  variation for  spectroscopic
observations.  

Description:
We  use  the  tungsten  lamp   and  the  MR  grism  to  determine  the
pixel-to-pixel   variation   of   the   STIS  CCD   in   spectroscopic
mode. G430M+50CCD or +52x2 are  used to "map" the whole sensitive area
of the detector.

In addition tungsten flats with  LR grisms (G430L and G750L) are taken
with the  purpose of mapping of  the dust motes  which are illuminated
from different angle with respect to the MR grisms. The "observing"
strategy  is  similar  to that  for  the  MR  grisms, i.e.  50CCD  and
"stepped-52x2" flats  are collected and  combined in order to  map -at
high  SNR (>=400)-  the  whole  sensitive area  of  the detector.  The
additional LR grating  (G750L) is required to increase  the SNR on the
blue side of the detector.

The  program is  a continuation  of cycle  17 program  11852. However,
GAIN=1 G430M+50CCD  have been  removed, while the  number of  LR flats
have been increased.

Accuracy:              <= 1%
Comments on Accuracy:  How well the spectroscopic science  data can be
flattened.
Products:              Reference files and ISR.


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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.............................:Tungsten       
Flux (and units)........................:Internal Tungsten Lamp

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

Target or lamp..........................: Tungsten lamp
Type of Acquisition.....................: n/a
Detector for observation................: CCD
Operating mode .........................: ACCUM
Spectral Element........................: G430M
Aperture................................: 50CCD
Central Wavelength......................: 5216
Exposure Time...........................: 21s, crsplit=no
Number of Iterations ...................: 9  (X 9 visits)
ETC PID IDs for Count Rates.............: 
Special Requirements or options.........: GAIN=4, 
Comments: One visit (9 flats) every 41 days.

Target or lamp..........................: Tungsten lamp
Type of Acquisition.....................: n/a
Detector for observation................: CCD
Operating mode .........................: ACCUM
Spectral Element........................: G430L
Aperture................................: 50CCD
Central Wavelength......................: 4300
Exposure Time...........................: 2.5s X 13, crsplit=no
Number of Iterations ...................: 13 (X 5 visits)
ETC PID IDs for Count Rates.............: 
Special Requirements or options.........: GAIN=4
Comments: Do three visits early, and repeat two more at intervals of 4
months.

Target or lamp..........................: Tungsten lamp
Type of Acquisition.....................: n/a
Detector for observation................: CCD
Operating mode .........................: ACCUM
Spectral Element........................: G750L
Aperture................................: 50CCD
Central Wavelength......................: 7751
Exposure Time...........................: 0.6s x 13, crsplit=no
Number of Iterations ...................: 13 (X 3 visits)
ETC PID IDs for Count Rates.............: 
Special Requirements or options.........: GAIN=4
Comments: Do all three visits early.

Target or lamp..........................: Tungsten lamp
Type of Acquisition.....................: n/a
Detector for observation................: CCD
Operating mode .........................: ACCUM
Spectral Element........................: G430M
Aperture................................: 52X2
Central Wavelength......................: 5216
Exposure Time...........................: 550s X 2, crsplit=no
Number  of   Iterations  ...................:   2  (X  10   visits;  1
slit-steps/visit and 5 slit-steps in total).
ETC PID IDs for Count Rates.............: 
Special Requirements or  options.........: GAIN=4, dither with special
slit-pos pattern
Comments:  Do once  early in  Cycle-18.  Group all  visits within  one
annealing period.

Target or lamp..........................: Tungsten lamp
Type of Acquisition.....................: n/a
Detector for observation................: CCD
Operating mode .........................: ACCUM
Spectral Element........................: G430L
Aperture................................: 52X2
Central Wavelength......................: 4300
Exposure Time...........................: 59s x 2, crsplit=no
Number of Iterations  ...................: 2/slit-steps X 3 slit-steps
(X 6 visits) + 3/slit-steps X 2 slit-steps (X 4 visits).  In total, at
the end of  the 10 visits, each slit-steps will  have been observed 12
times.
ETC PID IDs for Count Rates.............: 
Special Requirements or  options.........: GAIN=4, dither with special
slit-pos pattern
Comments: Do all visits early.   As slit-pos cannot be changed without
moving the  aperture, one  clear aperture exposure  can also  be taken
between the slit-pos changes.


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# Special needs of this proposal?

Scheduling: 

Prerequisites: n/a

PDB update?     n/a
On-board table update?    n/a

# Special Requirements:
Real time?                N
Special commanding?       N
Quick Data turnaround?    N
Special timing required?  N
Other?                    N
Describe (& justify) special requirements:

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# Link to Cycle 18 Science
# Use the GO + GTO Phase 1 exposure listing and derived statistics
# posted on WWW.

Fraction of  science programs supported  by this calibration:  15% (of
STIS)

List categories  of science which  can't be executed until  after this
proposal: None.

List categories  of science  which are best  performed contemporaneous
with this proposal:  High S/N CCD spectroscopy 
why: For  programs that need  very high S/N,  it would be best  if the
epoch of the flats spans the observations.  So the flat program should
be spread out over the whole cycle.

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# Analysis Plan

Expected FTE weeks for analysis:                               	4
Required turnaround on analysis (weeks):                       	4
Data volume (Mb needed for analysis):                         	2000
Special software needed for analysis? (Describe):             	None

Description of analysis Plans:  
Do statistical  analysis of data  yearly to check for  any significant
changes in pixel-to-pixel flats. Co-add  G430M flats after 8 weeks and
then again  at end of cycle to  make new pfl files.   Co-add G430L and
G750L data  to make L-flat for L  models. Also use G750L  data to make
independent Lflat, and compare to G430L to estimate red-halo scattered
light effects.