| | 28 | * Catching up following absence |
| | 29 | * 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. |
| | 30 | * Image subtraction |
| | 31 | * 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 |
| | 32 | * 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? |
| | 33 | * Penalty = 0 for odd basis functions: encourages basis functions that will produce an artificial astrometric shift. Changed penalty function to sum K^2^ r^4^. |
| | 34 | * 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). |
| | 35 | * Artificially forcing single convolution within the framework of dual convolution to verify behaviour. |
| | 36 | * Tracked down error in dual convolution: multiple sign errors. |
| | 37 | * 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. |
| | 38 | * Without SVD, matching two Gaussians with different widths results in kernels with a non-zero moment: potentially bad for astrometry (especially of asteroids). |
| | 39 | |
