theta_grid

screens.fields.theta_grid(d_eff, mu_eff, fobs, dtau, tau_max, dfd, fd_max)

Make a grid of theta that sample the parabola in a particular way.

The idea would be to impose the constraint that near tau_max the spacing is roughly the spacing allowed by the frequencies, and near the origin that allowed by the times. In practice, one needs to oversample in both directions, by about a factor 1.3 in tau (which makes some sense from wanting to sample resolution elements with about 3 points, not just 2 for a FFT), but by about a factor 1.6 in f_d, which is less clear.

Parameters:

d_effQuantity

Effective distance. Should be constant; if different for different points, no screen-to-screen scattering is taken into account.

mu_effQuantity

Effective proper motion (v_eff / d_eff), parallel to theta_par.

fobsQuantity

Mean frequency for which the doppler factor should be calculated.

dtauQuantity

Requested spacing in delay (typically should somewhat oversample the spacing in the secondary spectrum).

tau_maxQuantity

Maximum delay to consider. Can be up to the value implied by the the frequency resolution (i.e., 1/(f[2]-f[0])).

dfdQuantity

Requested spacing in doppler factor (typically should oversample the spacing in the secondary spectrum).

fd_maxQuantity

Maximum doppler factor to consider. Can be up to the value implied by the time resolution (i.e., 1/(t[2]-t[0])).