Some calculations to assist with building the DESI model from an existing ZEMAX model and other sources.
You can safely ignore this if you just want to use the model.
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import batoid
from batoid.utils import normalized
import yaml
import numpy as np
from ipywidgets import interact
import ipywidgets as widgets
import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D
%matplotlib inline
Load the DESI model:
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fiducial_telescope = batoid.Optic.fromYaml("DESI.yaml")
Setup YAML to preserve dictionary order and trunctate distances (in meters) to 5 digits:
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import collections
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def dict_representer(dumper, data):
return dumper.represent_dict(data.items())
yaml.Dumper.add_representer(collections.OrderedDict, dict_representer)
def float_representer(dumper, value):
return dumper.represent_scalar(u'tag:yaml.org,2002:float', f'{value:.5f}')
yaml.Dumper.add_representer(float, float_representer)
Define the corrector internal baffle apertures, from DESI-4103-v1. These have been checked against DESI-4037-v6, with the extra baffle between ADC1 and ADC2 added:
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# baffle z-coordinates relative to FP in mm from DESI-4103-v1, checked
# against DESI-4037-v6 (and with extra ADC baffle added).
ZBAFFLE = np.array([
2302.91, 2230.29, 1916.86, 1823.57, 1617.37, 1586.76, 1457.88, 1349.45, 1314.68,
1232.06, 899.67, 862.08, 568.81, 483.84, 415.22])
# baffle radii in mm from DESI-4103-v1, checked
# against DESI-4037-v6 (and with extra ADC baffle added).
RBAFFLE = np.array([
558.80, 544.00, 447.75, 417.00, 376.00, 376.00, 378.00, 378.00, 395.00,
403.00, 448.80, 453.70, 492.00, 501.00, 496.00])
Calculate batoid Baffle surfaces for the corrector. These are mechanically planar, but that would put their (planar) center inside a lens, breaking the sequential tracing model. We fix this by use spherical baffle surfaces that have the same apertures. This code was originally used to read a batoid model without baffles, but also works if the baffles are already added.
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def baffles(nindent=10):
indent = ' ' * nindent
# Measure z from C1 front face in m.
zbaffle = 1e-3 * (2425.007 - ZBAFFLE)
# Convert r from mm to m.
rbaffle = 1e-3 * RBAFFLE
# By default, all baffles are planar.
nbaffles = len(zbaffle)
baffles = []
for i in range(nbaffles):
baffle = collections.OrderedDict()
baffle['type'] = 'Baffle'
baffle['name'] = f'B{i+1}'
baffle['coordSys'] = {'z': float(zbaffle[i])}
baffle['surface'] = {'type': 'Plane'}
baffle['obscuration'] = {'type': 'ClearCircle', 'radius': float(rbaffle[i])}
baffles.append(baffle)
# Loop over corrector lenses.
corrector = fiducial_telescope['DESI.Hexapod.Corrector']
lenses = 'C1', 'C2', 'ADC1rotator.ADC1', 'ADC2rotator.ADC2', 'C3', 'C4'
for lens in lenses:
obj = corrector['Corrector.' + lens]
assert isinstance(obj, batoid.optic.Lens)
front, back = obj.items[0], obj.items[1]
fTransform = batoid.CoordTransform(front.coordSys, corrector.coordSys)
bTransform = batoid.CoordTransform(back.coordSys, corrector.coordSys)
_, _, zfront = fTransform.applyForward(0, 0, 0)
_, _, zback = bTransform.applyForward(0, 0, 0)
# Find any baffles "inside" this lens.
inside = (zbaffle >= zfront) & (zbaffle <= zback)
if not any(inside):
continue
inside = np.where(inside)[0]
for k in inside:
baffle = baffles[k]
r = rbaffle[k]
# Calculate sag at (x,y)=(0,r) to avoid effect of ADC rotation about y.
sagf, sagb = front.surface.sag(0, r), back.surface.sag(0, r)
_, _, zf = fTransform.applyForward(0, r, sagf)
_, _, zb = bTransform.applyForward(0, r, sagb)
if zf > zbaffle[k]:
print(f'{indent}# Move B{k+1} in front of {obj.name} and make spherical to keep model sequential.')
assert isinstance(front.surface, batoid.Sphere)
baffle['surface'] = {'type': 'Sphere', 'R': front.surface.R}
baffle['coordSys']['z'] = float(zfront - (zf - zbaffle[k]))
elif zbaffle[k] > zb:
print(f'{indent}# Move B{k+1} behind {obj.name} and make spherical to keep model sequential.')
assert isinstance(back.surface, batoid.Sphere)
baffle['surface'] = {'type': 'Sphere', 'R': back.surface.R}
baffle['coordSys']['z'] = float(zback + (zbaffle[k] - zb))
else:
print(f'Cannot find a solution for B{k+1} inside {obj.name}!')
lines = yaml.dump(baffles)
for line in lines.split('\n'):
print(indent + line)
baffles()
Validate that the baffle edges in the final model have the correct apertures:
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def validate_baffles():
corrector = fiducial_telescope['DESI.Hexapod.Corrector']
for i in range(len(ZBAFFLE)):
baffle = corrector[f'Corrector.B{i+1}']
# Calculate surface z at origin in corrector coordinate system.
_, _, z = batoid.CoordTransform(baffle.coordSys, corrector.coordSys).applyForward(0, 0, 0)
# Calculate surface z at (r,0) in corrector coordinate system.
sag = baffle.surface.sag(1e-3 * RBAFFLE[i], 0)
z += sag
# Measure from FP in mm.
z = np.round(2425.007 - 1e3 * z, 2)
assert z == ZBAFFLE[i], baffle.name
validate_baffles()
Calculate simplified vane coordinates using parameters from DESI-4110-v1:
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def spider(dmin=1762, dmax=4940.3, ns_angle=77, widths=[28.5, 28.5, 60., 19.1],
wart_r=958, wart_dth=6, wart_w=300):
# Vane order is [NE, SE, SW, NW], with N along -y and E along +x.
fig, ax = plt.subplots(figsize=(10, 10))
ax.add_artist(plt.Circle((0, 0), 0.5 * dmax, color='yellow'))
ax.add_artist(plt.Circle((0, 0), 0.5 * dmin, color='gray'))
ax.set_xlim(-0.5 * dmax, 0.5 * dmax)
ax.set_ylim(-0.5 * dmax, 0.5 * dmax)
# Place outer vertices equally along the outer ring at NE, SE, SW, NW.
xymax = 0.5 * dmax * np.array([[1, -1], [1, 1], [-1, 1], [-1, -1]]) / np.sqrt(2)
# Calculate inner vertices so that the planes of the NE and NW vanes intersect
# with an angle of ns_angle (same for the SE and SW planes).
angle = np.deg2rad(ns_angle)
x = xymax[1, 0]
dx = xymax[1, 1] * np.tan(0.5 * angle)
xymin = np.array([[x - dx, 0], [x - dx, 0], [-x+dx, 0], [-x+dx, 0]])
for i in range(4):
plt.plot([xymin[i,0], xymax[i,0]], [xymin[i,1], xymax[i,1]], '-', lw=0.1 * widths[i])
# Calculate batoid rectangle params for the vanes.
xy0 = 0.5 * (xymin + xymax)
heights = np.sqrt(np.sum((xymax - xymin) ** 2, axis=1))
# Calculate wart rectangle coords.
wart_h = 2 * (wart_r - 0.5 * dmin)
wart_dth = np.deg2rad(wart_dth)
wart_xy = 0.5 * dmin * np.array([-np.sin(wart_dth), np.cos(wart_dth)])
plt.plot(*wart_xy, 'rx', ms=25)
# Print batoid config.
indent = ' ' * 10
print(f'{indent}-\n{indent} type: ClearAnnulus')
print(f'{indent} inner: {np.round(0.5e-3 * dmin, 5)}')
print(f'{indent} outer: {np.round(0.5e-3 * dmax, 5)}')
for i in range(4):
print(f'{indent}-\n{indent} type: ObscRectangle')
print(f'{indent} x: {np.round(1e-3 * xy0[i, 0], 5)}')
print(f'{indent} y: {np.round(1e-3 * xy0[i, 1], 5)}')
print(f'{indent} width: {np.round(1e-3 * widths[i], 5)}')
print(f'{indent} height: {np.round(1e-3 * heights[i], 5)}')
dx, dy = xymax[i] - xymin[i]
angle = np.arctan2(-dx, dy)
print(f'{indent} theta: {np.round(angle, 5)}')
print(f'-\n type: ObscRectangle')
print(f' x: {np.round(1e-3 * wart_xy[0], 5)}')
print(f' y: {np.round(1e-3 * wart_xy[1], 5)}')
print(f' width: {np.round(1e-3 * wart_w, 5)}')
print(f' height: {np.round(1e-3 * wart_h, 5)}')
print(f' theta: {np.round(wart_dth, 5)}')
spider()
Plot "User Aperture Data" from the ZEMAX "spider" surface 6, as cross check:
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def plot_obs():
wart1 = np.array([
[ -233.22959, 783.94254],
[-249.32698, 937.09892],
[49.02959, 968.45746],
[ 65.126976, 815.30108],
[ -233.22959, 783.94254],
])
wart2 = np.array([
[-233.22959, 783.94254],
[ -249.32698, 937.09892],
[49.029593, 968.45746],
[65.126976, 815.30108],
[-233.22959, 783.94254],
])
vane1 = np.array([
[363.96554,-8.8485008],
[341.66121, 8.8931664],
[1713.4345, 1733.4485],
[1735.7388, 1715.7068],
[363.96554,-8.8485008],
])
vane2 = np.array([
[-1748.0649, 1705.9022],
[ -1701.1084, 1743.2531],
[ -329.33513, 18.697772],
[ -376.29162, -18.653106],
[-1748.0649, 1705.9022],
])
vane3 = np.array([
[ -1717.1127, -1730.5227],
[ -1732.0605, -1718.6327],
[ -360.28728, 5.922682],
[-345.33947, -5.9673476],
[ -1717.1127, -1730.5227],
])
vane4 = np.array([
[ 341.66121, -8.8931664],
[363.96554, 8.8485008],
[1735.7388, -1715.7068],
[1713.4345, -1733.4485],
[ 341.66121, -8.8931664],
])
extra = np.array([
[ 2470 , 0 ],
[ 2422.5396 , -481.8731 ],
[ 2281.9824 , -945.22808 ],
[ 2053.7299 , -1372.2585 ],
[ 1746.5537 , -1746.5537 ],
[ 1372.2585 , -2053.7299 ],
[ 945.22808 , -2281.9824 ],
[ 481.8731 , -2422.5396 ],
[ 3.0248776e-13 , -2470 ],
[ -481.8731 , -2422.5396 ],
[ -945.22808 , -2281.9824 ],
[ -1372.2585 , -2053.7299 ],
[ -1746.5537 , -1746.5537 ],
[ -2053.7299 , -1372.2585 ],
[ -2281.9824 , -945.22808 ],
[ -2422.5396 , -481.8731 ],
[ -2470 , 2.9882133e-12 ],
[ -2422.5396 , 481.8731 ],
[ -2281.9824 , 945.22808 ],
[ -2053.7299 , 1372.2585 ],
[ -1746.5537 , 1746.5537 ],
[ -1372.2585 , 2053.7299 ],
[ -945.22808 , 2281.9824 ],
[ -481.8731 , 2422.5396 ],
[ 5.9764266e-12 , 2470 ],
[ 481.8731 , 2422.5396 ],
[ 945.22808 , 2281.9824 ],
[ 1372.2585 , 2053.7299 ],
[ 1746.5537 , 1746.5537 ],
[ 2053.7299 , 1372.2585 ],
[ 2281.9824 , 945.22808 ],
[ 2422.5396 , 481.8731 ],
[ 2470 , -1.0364028e-11 ],
[ 2724 , 0 ],
[ 2671.6591 , -531.42604 ],
[ 2516.6478 , -1042.4297 ],
[ 2264.9232 , -1513.3733 ],
[ 1926.1589 , -1926.1589 ],
[ 1513.3733 , -2264.9232 ],
[ 1042.4297 , -2516.6478 ],
[ 531.42604 , -2671.6591 ],
[ 3.3359379e-13 , -2724 ],
[ -531.42604 , -2671.6591 ],
[ -1042.4297 , -2516.6478 ],
[ -1513.3733 , -2264.9232 ],
[ -1926.1589 , -1926.1589 ],
[ -2264.9232 , -1513.3733 ],
[ -2516.6478 , -1042.4297 ],
[ -2671.6591 , -531.42604 ],
[ -2724 , 3.2955032e-12 ],
[ -2671.6591 , 531.42604 ],
[ -2516.6478 , 1042.4297 ],
[ -2264.9232 , 1513.3733 ],
[ -1926.1589 , 1926.1589 ],
[ -1513.3733 , 2264.9232 ],
[ -1042.4297 , 2516.6478 ],
[ -531.42604 , 2671.6591 ],
[ 6.5910065e-12 , 2724 ],
[ 531.42604 , 2671.6591 ],
[ 1042.4297 , 2516.6478 ],
[ 1513.3733 , 2264.9232 ],
[ 1926.1589 , 1926.1589 ],
[ 2264.9232 , 1513.3733 ],
[ 2516.6478 , 1042.4297 ],
[ 2671.6591 , 531.42604 ],
[ 2724 , -1.1429803e-11 ],
[ 2470 , 0 ],
])
plt.figure(figsize=(20, 20))
plt.plot(*wart1.T)
plt.plot(*wart2.T)
plt.plot(*vane1.T)
plt.plot(*vane2.T)
plt.plot(*vane3.T)
plt.plot(*vane4.T)
plt.plot(*extra.T)
w = 1762./2.
plt.gca().add_artist(plt.Circle((0, 0), w, color='gray'))
plt.gca().set_aspect(1.)
plot_obs()
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