Skip to main content

Focus and Pointing Documentation

The bibliography below lists related reports, papers, and presentations produced by STScI. These documents supplement other papers from the scientific community on observed HST PSF variations and resulting attempts at calibration.

ISR TEL 2019: A Comprehensive Approach to HST Focal Plane Geometric Calibration
J. Sahlmann, E. Nelan, J. Averbukh, C. Cox, M. Lallo
August 6, 2019

ISR COS 2012-01: COS FUV Focus Determination for the G140L Grating
Describes the procedures for determining the COS FUV fine-focus for the G140L grating.
P. Ghavamian
October 3, 2012

ISR WFC3 2012-14: Breathing, Position Drift, and PSF Variations on the UVIS Detector
L. Dressel 
July 13, 2012

Keeping the Hubble Space Telescope in Focus 
SPIE paper describing the focus model details and development.
C. Cox & M. Lallo
June 1, 2012

Experience with the Hubble Space Telescope: 20 Years of an Archetype 
Optical Engineering paper describing the Hubble Mission, covering optical design and performance. Special emphasis is placed on the Space Telescope Science Institute's unique experience with Hubble's behavior as an astronomical telescope in the environment of low earth orbit for over two decades. 
M. Lallo
January 2012

20 Years of Hubble Space Telescope Optical Modeling using Tiny Tim 
SPIE paper describing the evolution and applications of the Tiny Tim PSF Simulation software package.
J. E. Krist & R. N. Hook
October 1, 2011

ISR TEL 2011-01: Evaluation of a Temperature-based HST Focus Model
Describes the performance of the current focus model which includes a new secular formula and updates to SI-specific offsets.
C. Cox & S.-M. Niemi
March 22, 2011

ISR WFC3 2011-07: High Contrast Imaging using WFC3/IR 
Presents results of performing both classical and LOCI (Locally Optimized Combination of Images) PSF subtractions on WFC3/IR images of a bright (V=6.9) star with simulated companions. 
A. Rajan et al.
February 10, 2011

ISR TEL 2010-02: HST Focus in SMOV4: Strategy for OTA Adjustment & SI Focus 
Describes the observatory-level effort to produce optimal focus during Servicing Mission Observatory Verification 4.
M. Lallo et al.
December 10, 2010

ISR TEL 2010-03: Phase Retrieval to Monitor HST Focus: II. Results Post-Servicing Mission 4 
Discusses the results of focus monitoring since the last HST Secondary Mirror adjustment in July 2009, after Servicing Mission 4. Examines current focus of ACS & WFC3. 
S.-M. Niemi & M. Lallo
December 7, 2010

ISR TEL 2010-01: Phase Retrieval to Monitor HST Focus: 1. WFC3 UVIS Software Implementation 
Describes the adaptation and calibration of HST phase retrieval code to WFC3, and its subsequent use for focus and image monitoring.
S.-M. Niemi et al.
July 20, 2010

ISR-WFC3 2009-46: WFC3 SMOV Programs 11425, 11435: IR Channel On-orbit Alignment 
Describes the setting of the IR channel corrector mechanisms for optimal image quality and confocality with the other SIs.
G.F. Hartig et al.
December 14, 2009

ISR WFC3 2009-45: WFC3 SMOV Programs 11424, 11434: UVIS Channel On-orbit Alignment 
Describes the setting of the UVIS channel corrector mechanisms for optimal image quality and confocality with the other SIs.
G.F. Hartig et al.
December 14, 2009

ISR WFC3 2009-38: WFC3 SMOV Programs 11436/8: UVIS On-orbit PSF Evaluation 
Assessment of image quality in the WFC3 UVIS channel on orbit, following its optical alignment to the HST OTA.
G.F. Hartig
November 10, 2009

ISR WFC3 2009-37: WFC3 SMOV Programs 11437/9: IR On-orbit PSF Evaluation 
Assessment of image quality in the WFC3 IR channel on orbit, following its optical alignment to the HST OTA.
G.F. Hartig
November 10, 2009

ISR WFC3 2008-41: WFC3 IR PSF Evaluation in Thermal-Vacuum Test #3 
Assessment of image quality of the WFC3 IR channel in a flight-like thermal-vacuum environment.
G.F. Hartig
September 16, 2008

ISR TEL 2008-02: The Cosmic Origins Spectrograph Pre-flight Aperture Model and SIAF.dat File
M. Lallo
September 10, 2008

ISR WFC3 2008-40, WFC3 UVIS PSF Evaluation in Thermal-Vacuum Test #3 
Assessment of image quality in the WFC3 UVIS channel in a flight-like thermal-vacuum environment.
G.F. Hartig
August 20, 2008

ISR WFC3 2008-014: WFC3 Support in Tiny Tim 
Discusses the extension of the PSF simulator, Tiny Tim, to model WFC3 PSFs.
R. Hook & F. Stoehr
June 27, 2008

ISR ACS 2008-03: HST Focus Variations with Temperature 
Describes the temperature-based HST focus model that is the basis of our current (post-2002) modeling tool.
D. Di Nino et al.
May 7, 2008

HST Focus & PSF Stability 
Telescopes Group Talk Series, Talk #1 
M. Lallo
September 19, 2007

ISR ACS 2007-12: ACS PSF Variations with Temperatures 
Describes observed PSF widths and their correlation with HST temperatures. Predates the temperature-based focus model detailed in Di Nino et al., (2008).
K. C. Sahu et al.
September 18, 2007

ISR TEL 2006-01: Modeling Aberrations in the Advanced Camera for Surveys 
Investigates the plausibility of optical misalignments as the cause of apparent aberration changes implied by phase retrieval of HRC PSFs. 
K. Houairi et al.
October 10, 2006

Temporal Optical Behavior of HST: Impact on Science Observations 
SPIE paper giving some discussion and examples that relate measurements of defocus wavefront error to characterizations more common to science data analysis (e.g. FWHM, and ellipticity).
R. B. Makidon et al.
May 2006

Temporal Optical Behavior of HST: Focus, Coma & Astigmatism History 
SPIE paper describing variations of HST aberrations as revealed by ongoing monitoring using phase retrieval techniques.
M. Lallo et al.
May 2006

ISR ACS 2006-01: PSFs, Photometry, and Astrometry for the ACS/WFC 
Develops and provides a method for characterizing the HST PSF using the "effective PSF". A given observed ACS WFC PSF can be fit by interpolating between an array of fiducial PSFs over the detector, and by employing a "perturbation PSF" to capture the time-variability due mainly to focus changes. Effective PSF grids for 6 common WFC filters are provided, along with FORTRAN code for performing this analysis.
J. Anderson & I. R. King.
February 2006

HST Temporal Optical Behavior: Models & Measurements with ACS 
HST Calibration Workshop presentation describing apparent behavior of coma, astigmatism, and focus in ACS/HRC, and their effects on measured PSF characteristics.
R. B. Makidon et al.
October 30, 2005

ISR TEL 2005-03: HST Temporal Optical Behavior & Current Focus Status 
Reviews the timescales, mechanisms, and importance of variations in aberrations (focus, coma, astigmatism). Presents focus status of the observatory.
M. Lallo et al.
October 27, 2005

ISR TEL 2005-02: Guiding Errors in 3-Gyro: Experience from WF/PC, WFPC2, STIS, NICMOS and ACS 
This report summarizes typical behavior gleaned from several observations with ACS, WF/PC, WFPC2, STIS and NICMOS.
R. L. Gilliland
February 20, 2005

Telescope Image Modeling (Tiny Tim) Handbook 
User's manual for "Tiny Tim". Software package for simulating HST PSFs. NOTE: this is the general User's Guide. It pre-dates WFC3 capability and the web-based user-input defocus values.
J. E. Krist
June 1, 2004

ISR ACS 2003-06: ACS WFC & HRC Field-dependent PSF Variations due to Optical and Charge Diffusion Effects
Examines PSF width and ellipticity variations over WFC and HRC field resulting from optical and charge diffusion effects.
J. E. Krist
June 25, 2003

Post-2003 Jitter File Description Document 
Defines the current format of the HST jitter file products. Supplement to the "Pre-2003 Jitter File Description Document" 
J. Baum
February 2, 2003

OTA Focus Review Memo 
Reviews focus history, mirror moves, and typical accuracies of measurements and commands.
M. Lallo
June 25, 2002

Pre-2003 Jitter File Description Document 
Archived document that specifies the HST jitter files prior to spring 2003; describes their interpretation and application. For observations after this date, see Post-2003 Jitter File Description Document 
M. Lallo
June 2, 2002

On-orbit Alignment & Imaging Performance of HST ACS 
SPIE paper documenting the on-orbit optical alignment of the ACS, with an assessment of residual aberrations and comparisons with models. Effects of HST OTA focus changes are also discussed.
G. F. Hartig et al.
January 2002

ISR OTA 2001-01: HST Focus in Year 2000 - A Review of the Cycle 9 Focus Monitor Program 
Discusses the state of HST focus during the science cycle following an HST refocusing in June 2000.
M. Lallo
February 14, 2001

SESD 97-01: Modelling HST Focal-Length Variations 
This report laid out the first attempt at a comprehensive temperature-based HST focus model. Though the specific model has since been replaced (Di Nino et al., 2008, & Cox 2011), the temperatures and temperature functions that most closely correlate with focus changes were first identified here. Also described was an attempt at a predictive model, expressing the focus function in terms of HST attitude parameters, rather than the resulting temperature changes. 
J. Hershey
June 1998

TIR WFPC2 1997-10: WFPC2 Photometry from Subtraction of Observed PSFs 
Based on observed PSFs from WFPC2 calibration programs, a series of PSF subtraction tests were performed and the resulting photometry analyzed.
J. Surdej et al.
October 3, 1997

Velocity Aberration Correction for Parallel Observations
C. Cox 
October 1, 1997

WFPC2 Photometry from Subtraction of TinyTim PSFs 
Describes a method for determining best fitting model PSFs for WFPC2/PC1 observations.
M. Rémy et al.
September 1997

NICMOS SM-2 SMOV Alignment Results
O. Lupie
August 6, 1997

ISR WFPC2 1997-01: Impact of Focus Drift on Aperture Photometry 
Examines the impact of long term and short term focus variations on small aperture photometry performed on WF & PC channels of WFPC2.
A. Suchkov & S. Casertano
January 31, 1997

Transforming Non-COSTAR Aperture Positions to the New Vehicle Reference
M. Lallo 
October 3, 1996

Attitude Determination and Target Location
C. Cox 
September 6, 1995

Phase-Retrieval Analysis of Pre- and Post-Repair HST images 
Applied Optics paper discussing phase retrieval techniques used for HST PSF monitoring and characterization.
J. E. Krist & C. J. Burrows
August 1, 1995

ISR OTA-18: Focus Monitoring and Recommendation for Secondary Mirror Move 
Focus monitoring and recommendation for secondary mirror move.
S. Casertano
January 3, 1995

An Investigation into the Guidance of FOC GTO 4073
S. Holfeltz 
June 7, 1994

A Determination of the Pointing History during FOS Scans of Mars
C. Cox 
December 1, 1993

SESD 1993-16: Orbital Focus Variations in the Hubble Space Telescope 
This report first described the relationship between observed HST orbital focus changes and temperatures differences measured at HST's Light Shield just fore of the Secondary Mirror.
P. Y. Bély et al.
August 1993

Pre-footer

HST Help Desk 

Please contact the HST Help Desk with any questions.