; BSCLN ;--------------------------------------------------------------- ;! Hogbom Clean on beam-switched difference image ;# TASK SINGLEDISH IMAGING ;----------------------------------------------------------------------- ;; Copyright (C) 1999 ;; Associated Universities, Inc. Washington DC, USA. ;; ;; This program is free software; you can redistribute it and/or ;; modify it under the terms of the GNU General Public License as ;; published by the Free Software Foundation; either version 2 of ;; the License, or (at your option) any later version. ;; ;; This program is distributed in the hope that it will be useful, ;; but WITHOUT ANY WARRANTY; without even the implied warranty of ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ;; GNU General Public License for more details. ;; ;; You should have received a copy of the GNU General Public ;; License along with this program; if not, write to the Free ;; Software Foundation, Inc., 675 Massachusetts Ave, Cambridge, ;; MA 02139, USA. ;; ;; Correspondence concerning AIPS should be addressed as follows: ;; Internet email: aipsmail@nrao.edu. ;; Postal address: AIPS Project Office ;; National Radio Astronomy Observatory ;; 520 Edgemont Road ;; Charlottesville, VA 22903-2475 USA ;----------------------------------------------------------------------- BSCLN LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC BSCLN Hogbom-like Clean on beam-switched difference image INNAME Plus image name (name) INCLASS Plus image name (class) INSEQ 0.0 9999.0 Plus image name (seq. #) INDISK 0.0 9.0 Plus image disk unit # IN2NAME Minus image name (name) IN2CLASS Minus image name (class) IN2SEQ 0.0 9999.0 Minus image name (seq. #) IN2DISK 0.0 9.0 Minus image disk unit # OUTNAME Output image name (name) OUTCLASS Output image name (class) OUTSEQ -1.0 9999.0 Output image name (seq. #) OUTDISK 0.0 9.0 Output image disk unit #. BLC Bottom left corner of input TRC Top right corner of input DPARM (1) Throw corr factor (2) Throw angle in degrees (3) Plus/minus beam height (4) Plus beam width corr. (5) Minus beam width corr. NITER Iterations FLUX Min flux for component GAIN 0.0 1.0 Gain BMAJ Output beam width (asec fwhm) NBOXES 0.0 50.0 Number Clean boxes CLBOX Clean boxes DOTV -1.0 10000. TV display control ---------------------------------------------------------------- BSCLN Task: Performs a Hogbom-like Clean on an image made by differencing two beam-switched images. At present, the beam is just two Gaussians (plus and minus) but position, width, strength corrections are made. The standard Hogbom algorithm searches for the maximum pixel in an image and sets a component at that pixel. BSCLN has a beam with a plus point one throw away from a component in one direction and a minus point one throw away in the opposite direction. So the peak of the difference of the residual image one plus throw from a pixel and one minus throw from that pixel is where BSCLN places a component. It helps convergence to have the throw length about an integer number of pixels. This is an experimental algorithm. Please inform Eric Greisen (egreisen@nrao.edu) of any experience you have with it. Adverbs: INNAME.....Input plus image name (name). Standard defaults. INCLASS....Input plus image name (class). Standard defaults. INSEQ......Input plus image name (seq. #). 0 => highest. INDISK.....Disk drive # of input plus image. 0 => any. IN2NAME....Input minus image name (name). Standard defaults. IN2CLASS...Input minus image name (class). Standard defaults. IN2SEQ.....Input minus image name (seq. #). 0 => highest. IN2DISK....Disk drive # of input minus image. 0 => any. OUTNAME....Output image name (name). Standard defaults. OUTCLASS...Output image name (class). Standard defaults. OUTSEQ.....Output image name (seq. #). 0 => highest unique. OUTDISK....Disk drive # of output image. 0 => highest disk number with sufficient space. BLC........Bottom right corner in input image of desired subimage. Default is entire image. TRC........Top right corner in input image of desired subimage. Default is entire image. DPARM......(1) Throw correction factor. The throw is read from the input image header as BSTHROW. 0 -> 1. (2) Throw angle in degrees (3) Ratio of plus beam to minus beam peaks. 0 -> 1. (4) Correction factor for plus beam width. 0 -> 1. (5) Correction factor for minus beam width. 0 -> 1. NITER......Number of Clean iterations. GAIN.......Clean loop gain BMAJ.......Output beam width (asec fwhm) NBOXES.....Number of Clean search areas. CLBOX......Clean boxes: rectangular xmin,ymin,xmax,ymax and circular -1,radius,xcenter,ycenter are supported. DOTV.......<= 0 => no TV display. > 0 => display residual image every DOTV iterations. There is no interaction. ----------------------------------------------------------------