Mirror STEP: testing the impact of mirror size
STEP home Simulations Data Mailing List

Simulated Images for Different Mirror Sizes

If you would like to analyze these images, please download them by December 5th, as they will be removed from the ftp site at that time.

If you want to be included in the study of how mirror size relates to accuracy of shear recovery, please try to complete the analysis by the end of January 2008. Let me know if you plan on participating by sending a brief email to jesford.shred[at]gmail.com. Otherwise the data is available for public use.

You can email your results and/or any questions to Jes Ford: jesford.shred[at]gmail.com. For more information you can download Jes' talk from the 2007 STEP workshop.

The images are available from ftp://ftp.astro.caltech.edu/pub/rhodes/rhodes/Jes_sims/

These images contain 13 different values of input shear, Gamma= [gamma1, gamma2]. With gamma1 set to zero, gamma2 takes on values of -5%, -3%, -1%, 0%, 1%, 3%, 5%, and vice-versa with gamma1 and gamma2 swapped. The mirror sizes included are 40cm, 80cm, 1.2m, 1.6m, 2.0m, and 2.4m in diameter, and there are separate images for galaxies and stars. One set of images were created at a constant exposure time of 1500 seconds, and one set was done at a constant photon flux, where the 1.2m mirror was taken to be at 1500 seconds and the other exposure times were varied accordingly. The total number of star/ galaxy image pairs is 143.

The naming convention for these files is as follows. They all begin with the letter i representing the filter (R-I-Z actually), followed by the date. Then there is the exposure time; every mirror size has a simulation at 1500, and one other time, all measured in seconds. Next is the mirror size (diameter), in meters. Then gamma1 and gamma2 are listed, as percentages. Clearly this is not intended to be a blind STEP-like test, as the input shears are known by participants.

For example: i_July24_1500_2.40000_neg3_0_noisy.fits

  • The i simply represents that these images use the wide R-I-Z filter
  • July24 is the approximate date this image was created
  • 1500 is the exposure time, in seconds
  • 2.40000 is the mirror diameter, in meters
  • neg3 tells you gamma1 is -3%
  • 0 is gamma2 (for each simulation atleast one of gamma1 or gamma2 is zero)
  • noisy just indicated that noise has been added to the image
note: the fact that there the word star is NOT in the image title tells you that this is a galaxy image. Stellar images have star just after the date, but are otherwise identical to their galactic counterpart: i_July24_star_1500_2.40000_neg3_0_noisy.fits

Last modified 16th Nov.
STEP pages maintained by Catherine Heymans: heymans[at]physics.ubc.ca
Questions regarding the Mirror STEP simulations should be directed to Jes Ford (jesford.shred[at]gmail.com), and Jason Rhodes (jason.d.rhodes[at]jpl.nasa.gov).