... Meta Index / Home Page / Description / Specifying source region shapes . When radiusstyle =`contour', the task calculates the source region shape as an elliptical locus which approximates the contour of the PSF at a given flux value. ... Clearly, in order to calculate the shape of such a flux contour, it is necessary firstly to normalize the PSF to the source brightness and secondly to determine the flux level (in `brightness' units per pixel) at which to find the contour. ...

... This paper describes the main algorithms used by the Einstein Level One processing to create the exposure masks and the background maps for Einstein IPC images, and how these algorithms were recreated in the IRAF environment. Our goal was to recreate the algorithms used by the Level One Processing to create exposure masks and background maps for Einstein Image Proportional Counter (IPC) data (cf. sections 2.5 and 2.7 of Harnden et al. ...

Target Acquisition Reference Information . ... In almost all cases where an onboard acquisition will not work (because the object is in a crowded field, or is variable, or is a moving target), it is sufficient to use an early acquisition to get a WFPC2 or FOC image a few weeks in advance of the GHRS observation. ... Explicit BRIGHT and FAINT limits may be specified if you desire, although there is an increased risk of a failed acquisition unless you are confident of those fluxes. ... MAPs . ...

. This diagram shows a small table with three transparent cells and illustrates how their final background is determined. The table consists of two rows. Four (labeled) cells lie in the first row, but the second cell spans the first and second row. The first, third, and fourth cells of the second row are "empty". Each non-empty cell has a red background and a double black border. Each empty cell has the table's background color (specified as #ff0) as its own. Return to image.

... User Guide ] Task: moment Purpose: Calculate moments of a Miriad image. ... Key: in The input image. No default. ... Key: mom -3: Velocity at peak intensity using a three-point quadratic fit around the peak (km/s). 2: Peak intensity using a three-point quadratic fit (units same as individual channels). ... The moments are calculated independently for each pixel using spectral channels with intensity satisfying the specified clip range. ... Key: axis Axis for which the moment is calculated. ...

Next: 1--Dimensional Images (``Spectra'') Up: 2--Dimensional Images Previous: Patterns . ... CREATE/RAMP . produces square two--dimensional images of user--specified dimensions, with mean flux per pixel of 100 units, of user--specified slope of the plane, and with the plane itself sloping at a position angle. ... CREATE/WAVE . ... Again, the image is two--dimensional, of user--specified dimensions, and with user--specified amplitude and period. ... The mean flux per period is 0 units. ...