ism3d.uvhelper.ft.advise_header

ism3d.uvhelper.ft.advise_header(uv, center, chanfreq, chanwidth, sortbyfreq=False, antsize=None)

create a header template for discreating cloudlet model before uv sampling

using accroding to UV sampling and primary beam FOV uv.shape (nrecord,2) in units of meter chanfreq quantity frequency array center this could be phasecenter or somewhere near your target antsize=12*u.m

f_max: determines the UV grid size, or set a image cell-size upper limit

a valeu of >=2 would be a safe choice (set a upper limit of cellsize)

f_min: set the UV cell-size upper limit, or a lower limit of image FOV.

a value of >=3 would be translated into a FOV lager than >=3 of interfeormetry sensitive scale ***set a lower limit of imsize

PB: primary beam size, help set a lower limit of FOV

however, in terms of imaging quality metric, this is not crucial ***set a lower limit of imsize

The rule of thumbs are:

• make sure f_max and f_min are good enought that all spatial frequency information is presented in

the reference models * the FOV is large enough to covert the object. * keep the cube size within the memory limit

# note: if dxy is too large, uvsampling will involve extrapolation which is not stable. # if nxy is too small, uvsampling should be okay as long as you believe no stucture-amp is above that scale. # interplate is more or less stable.