NICMOS Image Quality

The high image quality of NICMOS can be characterized by the Strehl ratio of the PSF, namely the ratio of the observed PSF to the TinyTim PSF peak fluxes. This ratio is very high for NICMOS, ranging from 0.8 to 0.9 at all wavelengths and in all cameras at their optimal focus. Important information on Image Quality can be found in the Image Quailty section of Chapter 4 of the NICMOS Instrument Handbook. For more specific details on NICMOS image quality, follow the links to the documents listed below.

NICMOS Image Quality Documentation

Advisories:
Important updates, discoveries and developments that could potentially affect NICMOS observations, calibration, or data analysis.

FAQs:
Frequently Asked Questions.

Performance Summaries:
Status reports reflecting the current understanding of instrument characteristics, performance and calibration.

Handbooks:
The NICMOS Instrument Handbook is the primary guide regarding the characteristics and use of the instrument. The HST Data Handbook is the primary guide for calibration, reduction and analysis of NICMOS data.

Instrument Science Reports:
ISRs are technical reports written by members of the NICMOS Group about various aspects of the instrument and data. They usually contain in-depth information about specific topics.

NICMOS ISR 2002-004: SM3b Science Flats
This report describes the results from the NICMOS pointed flat-field calibration program for SM3B. During programs 8998, 9557, and 9327, multiple sky background and lamp-on exposures were obtained for all filters with all cameras. Analysis of the DQE reveals that the relative countrates are at expected levels with respect to the operating temperature of 77K and are all within 8% of the ratio of modeled QE at 77K-to-62K performed during the 1997/1998 warm-up program. The resulting lamp-on minus background images were normalized to create the final calibration reference files.
L. Mazzuca 06 Oct 2002 (pdf)

NICMOS ISR 2002-002: NICMOS Cycle 10 Interim Calibration Plan
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 .
S. Arribas 14 Mar 2002 (pdf)

NICMOS ISR-99-011: Long-Term Trends in the NICMOS Camera 2 Obscuration Pattern and Aberrations
Phase retrieval measurements of well-exposed NICMOS Camera 2 star images show that long-term changes occurred in coma and the cold mask position over the 1997-1998 lifespan of the instrument. The derived trends have been implemented in Version 5 of Tiny Tim.
J. Krist 15 Nov 1999 (pdf)

NICMOS ISR-99-008: GROT in NICMOS Cameras
Grot is exhibited as small areas of reduced sensitivity, most likely due to flecks of anti-reflective paint scraped off the optical baffles as they were forced against each other. This paper characterizes grot associated with all three cameras. The main products of this analysis are grot masks for each of the cameras.
M. Sosey 20 Sep 1999 (pdf)

NICMOS ISR-99-007: NIC 2 Growth Curves
The Encircled Energy for isolated stars has been analyzed for NIC 2 F110W, F160W and F165M to quantify both spatial and temporal variations in the growth curve.
S. Holfeltz 13 Sep 1999 (pdf)

NICMOS ISR-98-015: NICMOS Focus and HST Breathing
Biweekly NICMOS focus monitoring measurements are compared with the predictions of the three OTA focus breathing models.
A. Suchkov 15 Sep 1998 (pdf)

NICMOS ISR-98-013: Second NIC3 Campaign Results
This report describes the point spread function (PSF) information for data taken in the second NICMOS camera 3 (NIC3) refocus campaign.
A. D. Storrs 13 Jul 1998 (pdf)

NICMOS ISR-98-009: Focus Variation and the Orbital Phase of Observations
We report the effects of cyclic OTA 'breathing' on focus position for a variety of observational strategies with special attention given to NICMOS coronagraphic observations of bright targets.
A. Storrs 14 May 1998 (pdf)

NICMOS ISR-98-007: Possible Evidence for NICMOS Focus 'Precessional Breathing'
Combining the results of measurements of NICMOS focus and temperature (outside NICMOS dewar), we have found a correlation between detrended NICMOS focus and detrended temperature. The correlation suggests that there is a thermally induced (quasi)periodic component in NICMOS focus variation which has a time scale resembling the HST precessional period.
A. Suchkov 01 May 1998 (pdf)

NICMOS ISR-98-004: NICMOS Focus Monitoring
We describe techniques to measure NICMOS foci and present the results of the NICMOS focus monitoring program as of February 1998. Procedures to correct for various affects which impact focus measurements are discussed.
A.Suchkov 16 Mar 1998 (pdf)

Papers and Proceedings:
Selected NICMOS related published papers and workshop proceedings.

Tutorials:
Cookbook style instructions, prescribed procedures, and helpful tips.

Examples:
Examples of how to use various NICMOS-related tools, calibration and analysis techniques.

Space Telescope Analysis Newsletters:
STANs contain useful information regarding calibration and data reduction.