class rubin_sim.maf.maf_contrib.FermatSpiralDitherFieldPerVisitStacker(ra_col='fieldRA', dec_col='fieldDec', field_id_col='fieldID', num_points=60, max_dither=1.75, gold_angle=137.508)

Bases: BaseStacker

Offset along a Fermat’s spiral with num_points, out to a maximum radius of max_dither. Sequential offset for each visit to a field.

Note: dithers are confined to the hexagon inscribed in the circle with with radius max_dither Note: Fermat’s spiral is defined by r= c*sqrt(n), theta= n*angle, n= integer

ra_col: str

name of the RA column in the data. Default: ‘fieldRA’.


name of the Dec column in the data. Default: ‘fieldDec’.


name of the fieldID column in the data. Default: ‘fieldID’.

num_points: int

number of points in the spiral. Default: 60

max_dither: float

radius of the maximum dither offset, in degrees. Default: 1.75

gold_angle: float

angle in degrees defining the spiral: theta= multiple of gold_angle Default: 137.508