IPP Progress Report for the week 2010.01.04 - 2010.01.08

(Up to IPP Progress Reports)

Eugene Magnier

Heather Flewelling

• preparing for UKIRT run next week (to observe MD fields)
• created (in previous week) preliminary scripts for nightly stacks. Tweaked them a bit more, released 12-27, 12-28, 1-04, 1-08.
• found interesting ripples in z and i band MD01 images. Chris and Gene discovered this was due to Mira.
• edited recipes: USE STDSCIENCE_VO FOR DATES < 2009-12-09 and DEFAULT FOR DATES > 2009-12-09! Pattern subtraction is on for dates < 2009-12-09, and off for dates after.
• processing: started SVS.20100108 and SweetSpot.20100108, consisting of SVS and SweetSpot (all) since 12-09-2009.

Bill Giebink

Roy Henderson

• enabled ability to switch types between IPP and PSPS using mapping file
• tried to learn enough Perl to write a script to run ippToPsps, without much success
• ran program through Valgrind, plugged memory leaks
• generally tidied up, made code safer, comments
• spoke with Jim and Conrad about example FITS file

Paul Price

• Catching up following absence
• Discovered source of ppImage memory bloat: darks are dramatically increasing the noise due to temperature being outside suitable range, causing tonnes of detections in psphot that swamp the memory.
• Image subtraction
  • Generated hotpants subtraction to compare with ppSub: ~/software/hotpants_v5.1.10/hotpants -inim image.gp.01.ch.fits -tmplim image.gp.02.ch.fits -ini image.gp.01.ch.wt.fits -tni image.gp.02.ch.wt.fits -outim image.gp.01-02.hp.diff.fits -oci image.gp.01-02.hp.conv.fits -oni image.gp.01-02.hp.var.fits -tu 1e5 -iu 1e5 -il -1e5 -tl -1e5 -tr 10 -ir 10 -ko 0 -bgo 0 -ng 3 2 0.85 2 1.70 2 3.4 -r 15 -fi 0 -fin 0 -convvar -savexy image.gp.01-02.hp.stamps -oki image.gp.01-02.hp.kernel -hki -v 2 > & image.gp.01-02.hp.log
  • Verified kernel basis functions convolved with image does not sum to zero, though kernel basis functions sum to zero. This is not due to use of FFT convolutions. We suspect edge and/or numerical effects. Slight reason for concern, perhaps?
  • Penalty = 0 for odd basis functions: encourages basis functions that will produce an artificial astrometric shift. Changed penalty function to sum K² r⁴.
  • SYS.ERR and SKY.ERR can really affect the derived normalisation and therefore the quality of the subtraction. Found that turning variance weighting off completely produces a better subtraction (presumably for the same reason Lupton advocates constant weighting for photometry).
  • Artificially forcing single convolution within the framework of dual convolution to verify behaviour.
  • Tracked down error in dual convolution: multiple sign errors.
  • Using SVD with trimming of low-significance singular values, but most important parts to the solution don't have high significance singular values, so tuning required for trim threshold. This is undesirable.
  • Without SVD, matching two Gaussians with different widths results in kernels with a non-zero moment: potentially bad for astrometry (especially of asteroids).

Bill Sweeney

Chris Waters