From fa080de7afc95aa1c19a6e6fc0e0708ced2eadc4 Mon Sep 17 00:00:00 2001 From: Joseph Hunkeler Date: Wed, 8 Jul 2015 20:46:52 -0400 Subject: Initial commit --- noao/digiphot/apphot/doc/apsums.noao | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) create mode 100644 noao/digiphot/apphot/doc/apsums.noao (limited to 'noao/digiphot/apphot/doc/apsums.noao') diff --git a/noao/digiphot/apphot/doc/apsums.noao b/noao/digiphot/apphot/doc/apsums.noao new file mode 100644 index 00000000..fd920b49 --- /dev/null +++ b/noao/digiphot/apphot/doc/apsums.noao @@ -0,0 +1,17 @@ +The apphot and daophot package aperture photometry tasks have been modified +to compute the aperture sums and areas in double precision instead of real +precision. This change minimizes machine precision errors that can become +significant for large apertures and very low noise or synthetic data. + +These tasks have also been modified to output negative values of the total +flux should they occur. Formerly these values were being artificially set to +0.0. This change makes it easier to see the effects of any sky value and machine +errors. + +The modified apertures photometry tasks are available under irafx. Let me +know if you have any questions about the modified tasks or encounter and +problems using them. + + + Lindsey Davis + davis@noao.edu -- cgit