Page tree

Versions Compared

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.


Content Block
overflowauto
meta-propertiestrue
nameSummary
id277319516
classpdf-full

JWST NIRCam subpixel dithers are small pointing offsets between exposures that mitigate an undersampled PSF and bad detector pixels.


Content Block
overflowauto
nameContent
id277805920
classpdf-full

Overview of NIRCam subpixel dithers

Parent pages: NIRCam Operations → NIRCam Dithers and Mosaics

NIRCam subpixel dithers are small pointing offsets performed between exposures in imaging, coronagraphy, and wide field slitless spectroscopy observations. They include subpixel offsets designed to mitigate undersampled PSFs. The available subpixel dither patterns serve different purposes for different observing modes:

  • NIRCam standard subpixel dithers, for imaging observations, are small telescope pointing maneuvers (0.2"–2") designed to optimally sample the PSF and improve the spatial resolution of stacked images.
  • NIRCam small grid dithers, for imaging and coronagraphy, are very small pointing shifts (<0.06") performed quickly and precisely with the fine steering mirror:
    • Imaging small grid dithers perform the same optimal pixel subsampling as standard subpixel dithers, but with smaller shifts performed with more efficiency.
    • Coronagraphy small grid dithers are designed to optimize PSF subtraction of a reference star from the science target.
  • NIRCam WFSS subpixel dithers (WFSS) are small telescope pointing maneuvers (~0.6") optimized to improve long wavelength grism observations and short wavelength simultaneously-obtained images.





Content Block
overflowauto
nameReferences
id281944791
classpdf-full

Anchor
ref
ref
References

Anderson, J. 2009, JWST-STScI-001738
Dither Patterns for NIRCam Imaging

Anderson, J. 2011, JWST-STScI-002199
NIRCam Dithering Strategies I: A Least Squares Approach to Image Combination

Anderson, J., 2014, JWST-STScI-002473
NIRCam Dithering Strategies II: Primaries, Secondaries, and Sampling

Coe, D. 2017, JWST-STScI-005798
More Efficient NIRCam Dither Patterns

Koekemoer, A. M. & Lindsay, K. 2005, JWST-STScI-000647
An Investigation of Optimal Dither Strategies for JWST

Lajoie, C-P et al., 2016, SPIE, 99045K
Small-grid dithers for the JWST coronagraphs





Content Block
overflowauto
nameIcon
id278719485
classpdf-hide

Multiexcerpt include
MultiExcerptNameNIRCam icon and name
PageWithExcerptMR:NIRCam icon and name


Content Block
nameUpdates
id1074221578
classpdf-hide


HTML Wrap
padding0
margin0
idupdatesbox


HTML Wrap
tagspan
classupdatesbox-heading

Last updated

Published February 9, 2018


Comment

The format for 'Last updated' is shown below. Enter updates above this internal"Comment" box. Only enter major updates (not typos or formatting changes).


Updated April 05, 2017

  • Lorem ipsum dolor sit amet, consectetur adipiscing elit. Aliquam fermentum vestibulum est. Cras rhoncus. 
  • Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Sed quis tortor. 

Published March 02, 2017