addfield adds a star field to a data frame generated with setfield and generates one or more images. It is possible to define a linear drift plus random jitter plus corrections every few frames to add to the positions for simulation of typical tracking. The offsets used are reported along with the frame name. See also noise.
addfield field data over [seed xd yd xrms yrms seeing1 seeing2 nreset nvary avary tvary pvary]
| field | --- | Name of the star field. |
| data | --- | data file or list of data files to add star field to. |
| over | --- | Oversampling factor (in terms of unbinned pixels). i.e. the stellar profile is computed on a grid spaced by 1/over pixels. 'over' must be > 0. This keeps better photometry especially when the profile is narrow, but takes longer to compute of course. |
| seed | --- | Random number seed. This and succeeding arguments is only prompted for there is more than 1 image |
| xdrift, ydrift | --- | Drift per image in x and y. |
| xrms, yrms | --- | RMS scatter in x and y. |
| seeing1 | --- | Starting seeing, in pixels. It is assumed that the profiles given are without any seeing added. Then a linear ramp of seeing will be added to them with image number. The seeing is added in quadrature to the semi-major and semi-minor axes of the ellipses. |
| seeing2 | --- | Ending seeing, in pixels. It is assumed that the profiles given are without any seeing added. |
| nreset | --- | Reset drift every nreset images. Simulates a position correction at the telescope. |
| nvary | --- | Number of aperture to vary sinusoidally in brightness |
| avary | --- | Fractional semi-amplitude of variation to impose |
| tvary | --- | t0 of variation, marking peak of brightness. |
| pvary | --- | Period of variation, in days |
This command is a member of the classes: Programs, Testing.
Author: T.R. Marsh
Created: 14 February 2002
Revised: 09 May 2006