Instrument Science Report NICMOS 2002-002
NICMOS Cycle 10 Interim
Calibration Plan
S.Arribas, D. Calzetti, S. Malhotra, E.Bergeron, T. Boeker, M. Dickinson,
S. Holfeltz, L. Mazzuca, B. Mobasher, K. Noll, E. Roye, A. Schultz, M. Sosey, C. Xu.
March 14, 2002
ABSTRACT
This document describes the NICMOS calibration activities for cycle 10 which will execute after the completion of the SMOV3b program and before the start of the routine Cycle
11 calibration program. These activities cover a period of approximately 5 months and
pursue the following objectives: i) enable calibration of the imaging mode for the three
cameras and all the spectral elements, ii) complete the calibrations of the spectroscopic
mode, iii) monitor during this period key aspects of the instrument (optics stability, detectors properties, scientific capability), and iv) to perform special calibrations (i.e. ‘gain
test’; accum-darks to support post-SAA observations) which were not implemented in the
SMOV3b program .
Introduction
The NICMOS SMOV-3b program is intended to demonstrate that the instrument is functioning as expected but, though it includes many calibration-related activities, does not
provide a full calibration of the science modes. For further details about the planned activities during SMOV see NICMOS Instrument Handbook for Cycle 11, page 200.
Full calibration of the instrument will be performed thanks to the routine calibration programs for each cycle (e.g., Calibration Program for Cycle 11 , and on) . The present
document refers to an interim calibration program which will be executed during the
period between SMOV3b and the nominal start of Cycle 11 and therefore it will extend
over a period of 3-5 months.
Copyright© 1999 The Association of Universities for Research in Astronomy, Inc. All Rights Reserved.
NICMOS Cycle 10 Interim Calibration Plan
Objectives
According to the current schedule (launching date February 28th, 2002), the period
between the end of SMOV to the start of cycle 11 will last 3 months. Obviously, the
present Interim Calibration Plan (ICP) can not provide a full calibration of all NICMOS
science capabilities. The objectives pursued for the ICP are:
i) Calibration of the imaging mode for the three cameras and all the spectral elements. The
imaging mode is by large the NICMOS science mode most commonly used.( During
Cycles 7 & 7N more than 80% of the exposures taken with NICMOS were in this mode).
A full calibration of this mode requires a number of individual calibration activities
(darks, flats, image quality & photometric stability, etc). The ICP will 1) provide with
flats for all narrow band filters (SMOV program 8985 includes wide, medium, and polarizer filters), 2) improve the accuracy of the darks taken during SMOV, and 3) study in a
greater detail the image quality and photometric stability of the instrument.
ii) Calibrations of the spectroscopic mode. This science mode was the second most used
during Cycles 7 & 7N with about 5.6% of the total number of exposures. The ICP will
provide with the flats for the narrow filters for NIC3, which together with the program
8991 executed during SMOV will allow calibration of this mode.
iii) Monitor of the main instrument properties. ICP includes four monitor programs
(‘darks’, ‘flats’, ‘focus’, ‘photometry’). These programs are considered key to understanding the behavior and stability of the instrument, specially under the current uncertainties
associated with the installation of the NCS. To provide continuity with similar programs
executed during SMOV, they will start as soon as possible (i.e. before the completion of
the SMOV). The ‘dark’ program (which will provide information about the linear component of the dark current, shading, and amplified glow, as well as the detector temperature
via the bias-based method proposed by Bergeron (2002, ISR in preparation), will execute
weekly. The other three programs will execute monthly.
iv) Special calibrations. ICP also includes two special calibrations. The ‘gain test’ aimed
to demonstrate the benefits of implementing a new gain value, and ‘accum darks’ to support post-SAA observations.
v) ICP will provide data necessary to implement the ‘Dark Generator’ and the ‘Flat Generator’ tools for generation of synthetic darks and flats, respectively. It is anticipated that
one of the objectives for the Cycle 11 calibration plan will be to test such tools in detail.
The polarimetric mode will be calibrated during cycle 11. As for coronography, SMOV
will demonstrate its possibilities, and a full calibration will depend on the GO demands.
2
NICMOS Cycle 10 Interim Calibration Plan
Estimated Time (orbits)
ID
Proposal Title
Frequency
Resources
Scheduling
Accuracy
Required Products
Required
Required
“External” “Internal”
(FTE)
Notes
Routine Monitoring Programs
9321 Dark current, shading profile, and weekly
read noise
63
after 8975
0.25
CDBS
4%
9323 Focus Stability
monthly
15
after 8980
0.3
ISR/IR
1mm
9325 Photometric Stability
monthly
10
after 8986
0.15
CDBS
2%
9326 Flat Stability
monthly
5
after 8985
0.15
IR/ISR
1%
Input for the ‘Dark Generator Tool’
Special Calibration Programs
9322 Accum Darks
monthly
9324 Gain Test
once
2
9327 Flats NIC1 (NIC2+NIC3)
once
9557 Flats NIC3
once
TOTAL TIME (including all executions)
5
after 8987
6
Needed for the CR persistence calibration
0.15
IR/ISR
13 (CVZ)
0.2
CDBS
3%
Needed for the ‘Flat Generater Tool’
3 (CVZ)
0.1
CDBS
3%
Needed for the grism calibration.
Needed for the ‘Flat Generator Tool’
48
74
1.4
Engineering Test
NICMOS Cycle 10 Interim Calibration Plan
Proposal ID 9321: NICMOS Cycle 10 ICP: Dark current, shading profile, and read noise
Plan
Purpose The purpose of this proposal is to monitor the detector dark current, read noise, and shading profile for all three NICMOS cameras from the onset of normal NCS operations throughout the
start of Cycle 11.
Description Each iteration of this proposal consists of ten dark exposures of
1088s (sample sequence of SPARS64 and NSAMP=19) for all 3
cameras. In addition, a set of 3 SCAMRR, NSAMP=25
sequences for each camera will be obtained in order to obtain an
accurate estimate of the read noise. Finally, in order to characterize the shading profile of the NICMOS detectors, a set of 5
STEP256, NSAMP=12 sequences for each camera are taken.
These contain all commonly used NICMOS Delta-times, except
the shortest one (0.2s) which is covered by the SCAMRR
sequences. As an additional benefit, the dark exposures will
allow us to estimate the cosmic ray rates outside the SAA. This
sequence will be repeated once a week for 21 weeks to allow the
monitoring of NICMOS detector behavior as a function of both
time and temperature between the end of SMOV3B and the
beginning of Cycle 11.
Fraction 100%
GO/GTO
Supported
Resources Each weekly visit will require 3 internal orbits.
Required: Therefore, 63 internal orbits are required from Apr. to Aug.2002
Observation
Resources 0.25 FTE
Required:
Products Darks for all readout sequences.
Accuracy 4-5 % per visit for the linear component of the dark current. In
Goals principle S/N ~ 50, but degradation due to CR lower this figure.
S/N ~ 35 (12) for the amplifier glow at the corner (center).
Scheduling& weekly after proposal 8975 is executed (currently 3/24/02).
Special
Requirements
4
NICMOS Cycle 10 Interim Calibration Plan
Proposal ID 9322: NICMOS Cycle 10 ICP: Accum. Darks
Plan
Purpose The goal is to obtain ACCUM darks with exposure time=256
seconds with NREADS=25, taken away from the SAA. These
are needed to calibrate the post-SAA darks that will be used to
remove CR persistence from NICMOS science images. In the
early calibration plan they should be obtained every 4 weeks.
We will evaluate need for repeats later.
Description A set of 10 dark observations in all three cameras will be
obtained every 4 weeks from April 2001 until August 2001, for
a total of 5 repeats. Each set should be obtained within a period
of 8 hours, to ensure closeness in Temperature and that they are
obatined within a single SAA-free period..
Fraction 20%
GO/GTO
Programs
Supported
Resources Each monthly visit will be 1 internal orbit
Required: Therefore, we will need 5 external orbits
Observation
Resources 0.10 FTE
Required:
Analysis
Products Darks files to the CDSB
Accuracy 5%. For each visit the S/N ~ 30 for the linear component of the
Goals DC. However, CR will degrade this figure.
Scheduling& These observations should be scheduled during earth occultaSpecial tions, well after SAA passages. Should be executed monthly,
Requirements after the SMOV proposal 8987.
5
NICMOS Cycle 10 Interim Calibration Plan
Proposal ID 9326: NICMOS Cycle 10 ICP: Flats Stability
Plan
Purpose A series of flat field observations will be obtain to monitor the
stability and health of the NICMOS detectorss
Description Each 1-orbit visit will obtain pointed flat fields in each
camera (NIC1 filters F110M, F110W, F160W; NIC2 filters
F110W, F160W,F222M; NIC3 filters F110W, F160W,
F222M).A four point dither pattern will be used to allow
removal of background objects. At each dithered position,
observations will be obtained with the lamp off and followed by
lamp on observations. Cameras 1 and 2 will be used in parallel.
For almost all the exposures, Lamp 1 (High Intensity) will be
used. The exposure times for the lamps-on are for the system
powered by the MEB-1 (the nominal flight configuration)
Fraction 100%
GO/GTO
Programs
Supported
Resources Each monthly visit will be one orbit. Therefore, 5 orbits are
Required: required for the complete period.
Observation
Resources 0.15 FTE
Required:
Analysis
Products Depending on the results an internal report or an ISR.
Accuracy 1 %
Goals
Scheduling& After SMOV proposal 8985 is executed
Special
Requirements
6
NICMOS Cycle 10 Interim Calibration Plan
Proposal ID 9327:NICMOS Cycle 10 ICP: Narrow flats NIC1( NIC2,NIC3)
Plan
Purpose This proposal obtains sequences of NICMOS narrow band filter
flat fields for camera 1. In cameras 2 and 3, parallel observations
will allow us to obtain high S/N flats for all spectral elements..
Description External flat field observations will be obtained with NIC1 for
all narrow band filters. The observations should be scheduled
close in time. At each dithered position, repeats will be
obtained for selected filters plus camera combinations with and
without the lamp on. For all the exposures, Lamp 1 (High Intensity) will be used. Parallel observations in cameras 2 and 3 will
allow us to obtain high S/N flats for all spectral elements. We
will compare these NIC3 flats with the ones obtained with proposal 9557
Fraction
GO/GTO
Programs
Supported
10% in a direct way. However, together with SMOV 8985, this
contains all the information needed by the ‘ Flat Generator Tool’
to create flats at any T and wavelength. Therefore, in an indirect
way this may support 100% of the GO programs.
Resources NIC 1 and NIC2 are in parallel and need 13 external orbits.
Required:
Observation
Resources 0.3 FTE
Required:
Analysis
Products High S/N flats will be delivered at CDBS
Accuracy 3 %
Goals
Scheduling& CVZ orbits
Special
Requirements
7
NICMOS Cycle 10 Interim Calibration Plan
Proposal ID 9324: NICMOS Cycle 10 ICP : Gain Test
Plan
Purpose Test of the viability and advantage of multiple NICMOS gain
settings.
Description Dark frames in all three Cameras in parallel for a total exposure
time of about 10,000 seconds will be obtained both at standard
gain (NTDGAIN=2) and at higher gain value (NTDGAIN=8).
This part of the observations will test whether digitization noise
is decreased by the higher gain. Flat-field frames in F160W in
all three cameras (plus associated background observations)
will be obtained for three gain values: 2, 4, and 8. This part of
the test will verify that multiple sets of reference files will not
be needed to support different gains if offered. Similar scope is
assigned to the observation of P330E in NIC2, F160W, at the
two gains 2 and 8..
Fraction 20%
GO/GTO
Programs
Supported
Resources 6 internal (darks) + 2 external (flats and photometry)
Required:
Observation
Resources 0.15 FTE
Required:
Analysis
Products Internal Report justifying the implemtation of the new gain
Accuracy
Goals
Scheduling& This proposal should execute as early as possible, compatibly
Special with SMOV3B proposals, but after NICMOS has reached final
Requirements focus
8
NICMOS Cycle 10 Interim Calibration Plan
Proposal ID 9323: NICMOS Cycle 10 ICP: Focus Stability
Plan
Purpose The purpose of this activity is to determine if the best focus
determined in SMOV is stable. This program will execute in
approximately one month intervals starting about 1 month after
the last execution of proposal 8980
Description This program is a version of the standard focus sweep used
since cycle 7. It has been modified to go deeper and uses narrower filters for improved focus determination.Steps: a) Use
refined target field positions as determined from cycle 7 calibrations b) Use MULTIACCUM sequences of sufficient dynamic
range to account for defocus c) Do a 17-point focus sweep, +/8mm about the PAM mechanical zeropoint for each cameras 1
and 2, in 1.0mm steps. d) Use PAM X/Y tilt and OTA offset
slew compensations refined from previous focus monitoring/
optical alignment activities e) Use encircled energy algorithms
to establish PAM focus and X/Y tilt positions for each camera.
.
Fraction 100%
GO/GTO
Programs
Supported
Resources Each monthly visit will be 5 external orbits. It should be exeRequired: cuted after SMOV 8980 (currently 5/16/02). Therefore, 5x3=15
Observation external orbits are required.
Resources 0.3 FTE
Required:
Analysis
Products ISR or IR
Accuracy The best focus should be known within 1 mm
Goals
Scheduling& Monthly after SMOV 8980 is executed for second time.
Special
Requirements
9
NICMOS Cycle 10 Interim Calibration Plan
Proposal ID 9325: NICMOS Cycle 10 ICP: Photometric Stability
Plan
Purpose This proposal carries out photometric monitoring observations
after SMOV3b, nominally spanning the approximate time frame
April-August 2002.
Description Photometric monitoring will be done for all three NICMOS
cameras. The filters to be used are: NIC1: F090M F110W
F160W F190N, NIC2: F110W F160W F190N F222M, NIC3:
F110W F160W F222M These choices provide monitoring in the
most commonly used broad band filters, plus a selection of additional filters spanning in wavelength. F110W, F160W are common to all three cameras, and there is one long-wavelength
filter in common for pairs of cameras (i.e., F190N for NIC1+2,
F222M for NIC2+3). NIC1 F090M provides one check on
behavior at the shortest wavelengths. All observations are done
using a spiral dither pattern,with 5 dither points for NIC1 and
NIC2, and 7 dithers forNIC3 . The integration times are set to
achieve S/N ~ 200-350 in the standard photometry apertures for
each exposure, while keeping peak pixel counts to < 66% of saturation. The NIC1/F190N observation has somewhat lower S/N
(~110) . NIC3/F110W may come slightly closer to saturation
(~73% according to the ETC). .
Fraction 100%
GO/GTOSupported
Resources : 10 external orbits (2 orbits per visit x 5 visits).
Observation
Resources 0.15 FTE
Analysis
Products Depending on the results an internal report or an ISR.
Acc. Goals 2 %
Scheduling& After SMOV proposal 8986 is executed Visits are scheduled
Special approximately every four weeks, from late April through
Requirements August.
10
NICMOS Cycle 10 Interim Calibration Plan
osal
Proposal ID 9557:NICMOS Cycle 10 ICP: Narrow filter flats for NIC3
Plan
Purpose This proposal obtains sequences of NICMOS Camera 3 to build
high S/N flat fields for all the narrow band filters and grisms.
Description External flat field observations will be obtained with NIC3 for
all narrow band filters and the GRISMs. The observations
should be scheduled close in time. At each dithered position
repeats will be obtained for selected filter/grism plus camera
combinations with and without the lamp on. For all narrow band
filters Lamp 1 (High Intensity) will be used, while a switch to
Lamp 2 is required for the grisms..
Fraction
GO/GTO
Programs
Supported
10% in a direct way. However, together with SMOV 8985, this
contains all the information needed by the ‘ Flat Generator Tool’
.It is also needed for the photometric and grism calibrations.
Therefore, in an indirect way this may support 100% of the GO
programs.
Resources NIC3 requires 3 additional external orbits
Required:
Observation
Resources 0.1 FTE
Required:
Analysis
Products High S/N flats will be delivered at CDBS
Accuracy 3 %
Goals
Scheduling& CVZ orbits
Special
Requirements
11