Proposal 13092 (STScI Edit Number: 0, Created: Wednesday, September 26, 2012 8:53:04 PM EST) - Overview
13092 - WFC3 IR Grisms: Flux Calibration Monitor
Cycle: 20, Proposal Category: CAL/WFC3
(Availability Mode: RESTRICTED)
INVESTIGATORS
Name
Dr. Janice C. Lee (PI) (Contact)
Dr. Norbert Pirzkal (CoI)
Mr. Bryan Hilbert (CoI)
Institution
Space Telescope Science Institute
Space Telescope Science Institute
Space Telescope Science Institute
E-Mail
jlee@stsci.edu
npirzkal@stsci.edu
hilbert@stsci.edu
VISITS
Visit Targets used in Visit
Configurations used in Visit
Orbits Used Last Orbit Planner Run
1A
WFC3/IR
2
(1) GD-153
26-Sep-2012 21:52:52.0
OP Current
with Visit?
yes
2 Total Orbits Used
ABSTRACT
This program enables monitoring of the WFC3 IR G102 and G141 grism calibrations for spectral image displacement and flux. The HST flux
standard GD-153 will be observed at three points over the field-of-view. GD-153 is prefered over GD-71 because it is a well-isolated object, and
does not suffer from contamination by nearby objects. The image displacement and throughput will be compared with Cycle 17, 18 and 19
measurements (from programs 11936, 12357 and 12702) to check for time evolution of these calibrations, and adjustments to the calibrations will be
made as necessary.
OBSERVING DESCRIPTION
The HST primary flux standard GD-153 will be observed at 3 different positions on the detector for each of the G102 and G141 grisms. As in
previous calibration programs, each dispersed exposure is preceeded by two direct images, to measure the source offsets between direct and dispersed
1
Proposal 13092 (STScI Edit Number: 0, Created: Wednesday, September 26, 2012 8:53:04 PM EST) - Overview
modes, and establish the wavelength zeropoint for each dispersed exposure. For the G102 (G140) observations, the F098M and F105W (F140W and
F160W) filters are used for the accompanying direct exposures. The number of FPA readouts (nsamp) is minimized for each exposure in order to
avoid as much visibility time lost to buffer dumps as possible. POSTARGs are used to move the first-order spectra to the desired positions on the
detector, and to dither the exposures taken at each position.
CALIBRATION JUSTIFICATION
Standard star observations with the grisms must be obtained to monitor the on-orbit flux calibration for the grism modes. Large-scale spatial
variations in overall instrument sensitivity must be also be monitored by obtaining standard star spectra at a few different positions on the detector.
This is vital for calibration of multi-object spectroscopic observations, where the targets of interest will be distributed over the entire FOV. The ratio
of the known flux distribution of GD-153 to the observed G102 and G141 spectra will produce an inverse sensitivity curve for each grism mode.
These sensitivity curves will be compared with those currently used within the ST-ECF aXe spectral extraction and calibration software to place all
WFC3 IR grism observations on an absolute flux scale. The spectral trace and image offset information
will also be derived from the observations, and checked against the current aXe calibration files.
Calibration products: Calibration files for sensitivity, spectral trace and image offset for first order spectra will be updated as necessary.
2
Fixed Targets
Visit
Proposal 13092 - Visit 1A - WFC3 IR Grisms: Flux Calibration Monitor
Proposal 13092, Visit 1A
Thu Sep 27 01:53:04 GMT 2012
Diagnostic Status: No Diagnostics
Scientific Instruments: WFC3/IR
Special Requirements: (none)
Comments: GD-153 for flux calibration of G102 (G141). 4x4 staggered pattern to fill FoV, including one pointing at FoV center. The observations at each field point consist of exposures in F098M, F105W, and G102
(F140W, F160W, and G141). Four G102 (G141) exposures are obtained at the central FOV position, using POSTARGS to manually create a small dither pattern. Single exposures in each spectral element are used at
the other field points. All field points use postargs to place the target relative to the default target location for the IR aperture, which is the only aperture available for use with the grisms. The direct exposures in the
direct-direct-grism sequence use the same offsets from the G102-REF (G141-REF) aperture, which is coincident with the IR aperture.
#
Name
Target Coordinates
Targ. Coord. Corrections
Fluxes
Miscellaneous
(1)
GD-153
RA: 12 57 2.3370 (194.2597375d)
V=13.4
Reference Frame: ICRS
Dec: +22 01 52.68 (22.03130d)
Equinox: J2000
Comments: According to ISR WFC3-2011-05, GD-153 is used as the primary flux calibrator for the WFC3 IR grisms.
3
Proposal 13092 - Visit 1A - WFC3 IR Grisms: Flux Calibration Monitor
#
1
2
3
4
5
6
Exposures
7
8
9
10
11
12
13
14
15
16
Label
Center 4x4
F098M
Target
(1) GD-153
Center 4x4
F105W
(1) GD-153
Center 4x4
G102
(1) GD-153
Center 4x4
G102
(1) GD-153
Center 4x4
G102
(1) GD-153
Center 4x4
G102
(1) GD-153
Config,Mode,Aperture
WFC3/IR, MULTIACCUM,
G102-REF
Spectral Els.
F098M
WFC3/IR, MULTIACCUM,
G102-REF
F105W
WFC3/IR, MULTIACCUM, IR
G102
WFC3/IR, MULTIACCUM, IR
WFC3/IR, MULTIACCUM, IR
WFC3/IR, MULTIACCUM, IR
G102
G102
G102
(3,2) 4x4 F0 (1) GD-153
98M
WFC3/IR, MULTIACCUM,
G102-REF
F098M
(3,2) 4x4 F1 (1) GD-153
05W
WFC3/IR, MULTIACCUM,
G102-REF
F105W
(3,2) 4x4 G1 (1) GD-153
02
WFC3/IR, MULTIACCUM, IR
G102
(3,2) 4x4 G1 (1) GD-153
02
WFC3/IR, MULTIACCUM, IR
(3,4) 4x4 F0 (1) GD-153
98M
WFC3/IR, MULTIACCUM,
G102-REF
F098M
(3,4) 4x4 F1 (1) GD-153
05W
WFC3/IR, MULTIACCUM,
G102-REF
F105W
(3,4) 4x4 G1 (1) GD-153
02
WFC3/IR, MULTIACCUM, IR
G102
(3,4) 4x4 G1 (1) GD-153
02
WFC3/IR, MULTIACCUM, IR
Center 4x4
F140W
(1) GD-153
WFC3/IR, MULTIACCUM,
G141-REF
F140W
Center 4x4
F160W
(1) GD-153
WFC3/IR, MULTIACCUM,
G141-REF
F160W
G102
G102
Opt. Params.
SAMP-SEQ=RAPID
;
NSAMP=2
SAMP-SEQ=RAPID
;
NSAMP=1
SAMP-SEQ=SPARS
25;
NSAMP=5
SAMP-SEQ=SPARS
25;
NSAMP=5
SAMP-SEQ=SPARS
25;
NSAMP=5
SAMP-SEQ=SPARS
25;
NSAMP=5
SAMP-SEQ=RAPID
;
NSAMP=2
SAMP-SEQ=RAPID
;
NSAMP=1
SAMP-SEQ=SPARS
25;
NSAMP=5
SAMP-SEQ=SPARS
25;
NSAMP=5
SAMP-SEQ=RAPID
;
NSAMP=2
SAMP-SEQ=RAPID
;
NSAMP=1
SAMP-SEQ=SPARS
25;
NSAMP=5
SAMP-SEQ=SPARS
25;
NSAMP=5
SAMP-SEQ=RAPID
;
NSAMP=2
SAMP-SEQ=RAPID
;
NSAMP=2
4
Special Reqs.
POS TARG -20.0,0
POS TARG -20.0,0
Groups
Exp. Time/[Actual Dur.]
Sequence 1-6 Non-In [==>]
t in Visit 1A
Orbit
[1]
Sequence 1-6 Non-In [==>]
t in Visit 1A
[1]
Sequence 1-6 Non-In [==>]
t in Visit 1A
[1]
Sequence 1-6 Non-In [==>]
t in Visit 1A
[1]
POS TARG -20.0,-2 Sequence 1-6 Non-In [==>]
t in Visit 1A
[1]
POS TARG -20.0,0. Sequence 1-6 Non-In [==>]
5
t in Visit 1A
[1]
POS TARG -4.0,-28. Sequence 7-10 Non-I [==>]
0
nt in Visit 1A
[1]
POS TARG -4.0,-28. Sequence 7-10 Non-I [==>]
0
nt in Visit 1A
[1]
POS TARG -4.0,-28. Sequence 7-10 Non-I [==>]
0
nt in Visit 1A
[1]
POS TARG -4.0,-26. Sequence 7-10 Non-I [==>]
0
nt in Visit 1A
[1]
POS TARG -4.0,34. Sequence 11-14 Non [==>]
0
-Int in Visit 1A
[1]
POS TARG -4.0,34. Sequence 11-14 Non [==>]
0
-Int in Visit 1A
[1]
POS TARG -4.0,34. Sequence 11-14 Non [==>]
0
-Int in Visit 1A
[1]
POS TARG -4.0,36. Sequence 11-14 Non [==>]
0
-Int in Visit 1A
[1]
POS TARG -20.0,0
POS TARG -20.0,2
POS TARG -20.0,0
POS TARG -20.0,0
Sequence 15-20 Non [==>]
-Int in Visit 1A
[2]
Sequence 15-20 Non [==>]
-Int in Visit 1A
[2]
Proposal 13092 - Visit 1A - WFC3 IR Grisms: Flux Calibration Monitor
17
18
19
20
21
22
23
24
25
26
27
28
Center 4x4
G141
(1) GD-153
Center 4x4
G141
(1) GD-153
Center 4x4
G141
(1) GD-153
Center 4x4
G141
(1) GD-153
WFC3/IR, MULTIACCUM, IR
WFC3/IR, MULTIACCUM, IR
WFC3/IR, MULTIACCUM, IR
WFC3/IR, MULTIACCUM, IR
G141
G141
G141
G141
(3,2) 4x4 F1 (1) GD-153
40W
WFC3/IR, MULTIACCUM,
G141-REF
F140W
(3,2) 4x4 F1 (1) GD-153
60W
WFC3/IR, MULTIACCUM,
G141-REF
F160W
(3,2) 4x4 G1 (1) GD-153
41
WFC3/IR, MULTIACCUM, IR
G141
(3,2) 4x4 G1 (1) GD-153
41
WFC3/IR, MULTIACCUM, IR
(3,4) 4x4 F1 (1) GD-153
40W
WFC3/IR, MULTIACCUM,
G141-REF
F140W
(3,4) 4x4 F1 (1) GD-153
60W
WFC3/IR, MULTIACCUM,
G141-REF
F160W
(3,4) 4x4 G1 (1) GD-153
41
WFC3/IR, MULTIACCUM, IR
G141
(3,4) 4x4 G1 (1) GD-153
41
WFC3/IR, MULTIACCUM, IR
G141
G141
SAMP-SEQ=SPARS
25;
NSAMP=5
SAMP-SEQ=SPARS
25;
NSAMP=5
SAMP-SEQ=SPARS
25;
NSAMP=5
SAMP-SEQ=SPARS
25;
NSAMP=5
SAMP-SEQ=RAPID
;
NSAMP=2
SAMP-SEQ=RAPID
;
NSAMP=2
SAMP-SEQ=SPARS
25;
NSAMP=5
SAMP-SEQ=SPARS
25;
NSAMP=5
SAMP-SEQ=RAPID
;
NSAMP=2
SAMP-SEQ=RAPID
;
NSAMP=2
SAMP-SEQ=SPARS
25;
NSAMP=5
SAMP-SEQ=SPARS
25;
NSAMP=5
5
POS TARG -20.0,0
Sequence 15-20 Non [==>]
-Int in Visit 1A
[2]
Sequence 15-20 Non [==>]
-Int in Visit 1A
[2]
POS TARG -20.0,-2 Sequence 15-20 Non [==>]
-Int in Visit 1A
[2]
POS TARG -20.0,0. Sequence 15-20 Non [==>]
5
-Int in Visit 1A
[2]
POS TARG -4.0,-28. Sequence 21-24 Non [==>]
0
-Int in Visit 1A
[2]
POS TARG -4.0,-28. Sequence 21-24 Non [==>]
0
-Int in Visit 1A
[2]
POS TARG -4.0,-28. Sequence 21-24 Non [==>]
0
-Int in Visit 1A
[2]
POS TARG -4.0,-26. Sequence 21-24 Non [==>]
0
-Int in Visit 1A
[2]
POS TARG -4.0,34. Sequence 25-28 Non [==>]
0
-Int in Visit 1A
[2]
POS TARG -4.0,34. Sequence 25-28 Non [==>]
0
-Int in Visit 1A
[2]
POS TARG -4.0,34. Sequence 25-28 Non [==>]
0
-Int in Visit 1A
[2]
POS TARG -4.0,36. Sequence 25-28 Non [==>]
0
-Int in Visit 1A
[2]
POS TARG -20.0,2
Orbit Structure
Proposal 13092 - Visit 1A - WFC3 IR Grisms: Flux Calibration Monitor
6
Proposal 13092 - Visit 1A - WFC3 IR Grisms: Flux Calibration Monitor
7