NAOMI
OMC/NCU Acceptance Tests at the University of Durham wht-naomi-44
DRAFT (Version date: 2nd June 2000)
The ID numbers are
those used in Dr. Andy Longmore’s Microsoft Access database (see AJL file:
integration_tests.mdb) which summarises the WPD requirements.
Most of the acceptance
tests listed in the database have been included in this document; some
selection of tests has been performed. The pressures of the schedule may lead
to significant reductions. In later versions of this document the author plans
to attach priorities to the tests and indicate test sequences for more
efficient operation, i.e. tests with similar configurations and requirements
should be grouped together. Notes in this draft have partially addressed the
need for grouping but a scheme that readily identifies similar tests is needed.
|
ID |
Objective |
Requirements |
Description of Test |
Date &Examiner |
Pass/ Fail |
Comments |
|
15 |
Verify that the
optics maintain the registration of the DM with the WFS lenslets independent
of the guide star position. |
·
OMC ·
WFS ·
NCU ·
Engineering
level GUI |
1.
The integrated
system is required for this test with the
Nasmyth focal plane mask installed. 2.
Select the WFS
fiducial mask and position the relay-lens/CCD carriage for the pupil-viewing
mode. 3.
Move the WFS
pickoff to the on-axis DL pinhole and verify the DM registration with the
fiducial mask. If not aligned adjust the DM x-y stage accordingly. Move the
WFS pickoff to at least 4 other field points and measure the DM/fiducial-mask
registration. 4.
0.115
subaperture misregistration is predicted due to non telecentricity. |
|
|
|
|
19 |
The NCU should
provide a WHT pupil simulator (for on-axis use only) |
·
NCU ·
OMC ·
WFS ·
Engineering
level GUI. |
1.
Measure the
f/ratio of the NCU output beam with the pupil mask in place. 2.
If brightness
is sufficient, verify that the pupil mask is imaged at the DM and its size is
correct (56 mm). 3.
If brightness
inadequate for visual observation at DM the pupil viewing mode of the WFS may
be used as follows. 4.
Flatten DM and
set FSM to midrange. 5.
Set WFS ADC to
zero dispersion and select doublet. 6.
Acquire on-axis
point source by moving WFS pickoff and centre in WFS FOV. 7.
Switch to WFS
pupil viewing mode. Verify pupil is in focus and record image for analysis.
Confirm that pupil size is acceptable. |
|
|
Test may be limited
by source brightness. |
|
20 |
NCU provide
capability to distortion map of AO optical train. |
·
NCU ·
OMC ·
WFS ·
Engineering
level GUI |
Capability is
demonstrated by performing test ID 22 in WFS acceptance tests. |
|
|
|
|
21 |
Average transmission
from Nasmyth focus to WFS input must be >0.58 over 0.5 to 0.8 mm (Mode 1). |
·
NCU ·
OMC ·
Engineering
level GUI. ·
ATC photometer
(or equivalent, e.g. SBIG camera) ·
0.5 -0.8mm filter |
1.
Flatten DM and
set FSM to midrange. 2.
With on-axis
point source, pupil mask and spectral filter measure NCU output flux. 3.
Measure flux
passing through centre of dichroic at WFS input and calculate transmission. |
|
|
|
|
41 |
Average transmission
from Nasmyth focus to WFS input must be >0.83 over 0.5 to 1.0 mm (Mode 1). |
·
NCU ·
OMC ·
Engineering
level GUI. ·
ATC photometer
(or equivalent, e.g. SBIG camera) ·
0.5 –1.0mm filter (if ATC photometer not available) |
1.
Flatten DM and
set FSM to midrange. 2.
With on-axis
point source, pupil mask and spectral filter measure NCU output flux. 3.
Measure flux
passing through edge of dichroic at WFS input by moving dichroic laterally.
Calculate transmission. |
|
|
|
|
51 |
Show that loop
closure can be maintained while dithering. |
·
NCU ·
OMC ·
WFS ·
Engineering
level GUI |
1.
Select NCU
on-axis point source, i.e. no FP mask. 2.
Flatten DM and
set FSM to midrange. 3.
Move WFS
pickoff to acquire point source and centre in WFS FOV. 4.
Close DM and
FSM loops. 5.
Setting the
configuration to the dither mode, inject an increasing amplitude, low
frequency tilt signal to the NCU tip/tilt mirror (maximum amplitude and
frequency TBD). 6.
Demonstrate
that the system can maintain loop closure while dithering. |
|
|
|
|
55 |
On-axis
common/science path wavefront error shall be <30 nm rms within a
subaperture (note exceptions in WPD). |
·
OMC ·
FISBA interferometer ·
Concave
spherical mirror and x, y & z mount (for use as retroreflector) |
1.
Install dummy
DM with pupil stop. 2.
Mount FISBA on
axis at the OMC input (Nasmyth focus). 3.
Install and
align concave sphere so that its centre of curvature is coincident with the
focused FISBA light at the WFS focus. 4.
Measure and
record the wavefront. Analyse for compliance. 5.
Move the
concave sphere to the science path and repeat the wavefront measurement.
Analyse for compliance. |
|
|
|
|
56 |
Off-axis
uncorrectable wavefront error over 1 arcmin field shall be <50 nm rms
(note exceptions in WPD) |
·
OMC ·
FISBA
interferometer ·
Concave
spherical mirror and x, y & z mount (for use as retroreflector) |
1.
Install dummy
DM with pupil stop. 2.
Mount FISBA at
+0.5 arcmin off axis in x at OMC input (Nasmyth focus). 3.
Install and
align concave sphere so that its centre of curvature is coincident with the
focused FISBA light at the WFS focus. 4.
Measure and
record the wavefront. Analyse for compliance. 5.
Repeat steps
2-5 for –0.5 arcmin in x and + 0.5 arcmin in y. |
|
|
-0.5 arcmin in y may
be omitted due to symmetry of the design. |
|
57 |
The pupil wavefront
error shall be <200 nm rms (goal < 170 nm) within 2 arcmin field. (Note
exceptions in WPD). |
·
OMC ·
FISBA
interferometer ·
Concave
spherical mirror and x, y & z mount (for use as retroreflector) |
1.
Follow same
procedure as for ID 56 except that FISBA and sphere are located at + 1
arcmin in x and y respectively. 2.
Determine rms
wavefront error over the pupil for each field position. |
|
|
|
|
58 |
The pupil wavefront
error shall be <300 nm rms (goal < 265 nm) within 2.9 arcmin field.
(Note exceptions in WPD). |
·
OMC ·
FISBA
interferometer ·
Concave
spherical mirror and x, y & z mount (for use as retroreflector) |
1.
Follow same
procedure as for ID 56 except that FISBA and sphere are located at +
1.45 arcmin in x and y respectively. 2.
Determine rms
wavefront error over the pupil for each field position. |
|
|
|
|
60 |
Non-common path
errors between science path and WFS shall be < 100 nm rms |
·
OMC ·
WFS ·
FISBA
interferometer ·
Concave
spherical mirror and x, y & z mount (for use as retroreflector) |
1.
Calibrate
wavefront quality of concave spherical mirror using the FISBA. Retain
wavefront data for use in other tests that follow. 2.
Set up the
FISBA on axis at the input (Nasmyth focus) to the OMC. WFS should not be in
position. 3.
Flatten the DM
or install the dummy DM. 4.
Install and
align the concave spherical mirror at the IR science port so that the IR
science path can be measured in double pass with the FISBA. Measure and
record the wavefront. 5.
Move the
concave sphere so that its centre of curvature lies at the WFS input focus.
Measure and record the input wavefront to the WFS. Remove sphere. 6.
Install the WFS
and move its pickoff so that the FISBA light passes through to the optical
science port (OSP). Reposition the sphere to allow a double-pass wavefront
measurement to the OSP. Measure and record the wavefront. 7.
Determine the
non-common path errors from the measured wavefronts. |
|
|
|
|
77 |
Measures shall be
taken to protect personnel from hazards. |
·
OMC ·
NCU ·
Engineering
level GUI |
Verify compliance
with documented safety audit. Procedure to be established when document is
made available to Durham. |
|
|
|
|
78 |
Handling procedures
and lifting aids should be provided for heavy items. |
·
NCU ·
OMC ·
Lifting aids
(e.g. handles) |
Verify availability
and function of lifting aids when demonstrating installation and alignment
(or disassembly on completion of tests). |
|
|
|
|
94 |
SciOpReq Clauses 1 –
3 performance achievable for 1 hour integrations without recalibration |
·
NCU ·
OMC ·
WFS ·
Engineering
level GUI |
Test operations to
be defined later. Test is identical to WFS test ID 144 in AJL database. |
|
|
|
|
95 |
The uncorrectable
tip/tilt induced jitter shall be < 30 nrad (0.006 arcsec) in WHT object
space. Note the inclusion of the WFS in the specification. |
·
WFS ·
NCU ·
OMC ·
Engineering
level GUI ·
SBIG camera |
1.
Flatten DM and
set FSM to midrange. 2.
Install SBIG
camera at the optical science port to view DL pinhole in FP mask. 3.
Align WFS to
suitable pinhole in FP mask without obscuring image of the SBIG camera. 4.
Measure PSF
width at science port with WFS power sources off. 5.
Turn on WFS
power sources. Close FSM loop. Measure PSF width again. Determine change in
width. Note: This test is
similar to the WFS test ID 146 which also lacks a satisfactory procedure. |
|
|
Test requires
further thought. Difficult to distinguish uncorrectable tilt from other
sources of PSF degradation. |
|
97 |
Cleaning procedures
demonstrated on witness samples of all coatings. |
·
Witness samples ·
Cleaning
materials and procedures |
1.
If a suitable
spectrophotometer is available the transmittance or reflectance of all
witness samples should be measured before and after cleaning. 2.
Perform
cleaning in accordance with documentation. Verify that the cleaning does not
leave residue or cause damage. |
|
|
|
|
100 |
Verify that the DM
and its associated electronics on bench can be removed and re-installed
safely in 1 hour or less. |
·
OMC ·
NCU ·
WFS ·
Engineering
level GUI |
1.
Flatten DM and
set FSM to midrange. Select on-axis point source in NCU. 2.
Select lenslet
1 and 4 x 4 pixel mode. Set ADC dispersion to zero. 3.
Acquire and
centre point source image in WFS by moving its pickoff. 4.
In pupil
viewing mode verify that DM segments are aligned to lenslets. If not adjust
DM x-y position as required. 5.
Turn off all
power to system. 6.
Remove and
re-install DM and bench-mounted electronics, noting time required for
complete operation. |
|
|
|
|
101 |
Verify that only
further minor alignment is needed on re-installation of DM. |
·
OMC ·
NCU ·
WFS ·
Engineering
level GUI |
This test is a
continuation of the procedure for test ID 100. 1.
Power up the
system and check for the image of the point source and pupil alignment in the
WFS. 2.
If re-alignment
is required, verify that it is minor, i.e. within limits of adjustments
provided. |
|
|
|
|
103 |
Verify that there is
at least + 4mm of travel on the DM motorized stages. |
·
OMC ·
Engineering
level GUI. ·
Travelling
microscope or equivalent |
1.
Set up
travelling microscope to view a reference point on the DM, e.g. segment
boundary. Take care not to touch the DM surface. 2.
Command the DM
x-y stage drive to each limit of travel and measure distance moved with the
travelling microscope. Verify travel is acceptable. |
|
|
|
|
104 |
Verify that DM
motorized stage motions are repeatable to < 0.2 mm. |
·
OMC ·
Engineering
level GUI. ·
Travelling
microscope or equivalent |
This test should be
combined with test ID 103. 1.
Set up travelling
microscope to view a reference point on the DM, e.g. segment boundary. Take
care not to touch the DM surface. 2.
Command the x-y
stage to drive set distances (TBD) repeatedly and measure position after each
command with the travelling microscope. Verify that the repeatability is
acceptable. |
|
|
|
|
110 |
Verify that the FSM
is protected against being driven to limits of its safe operational range. |
·
OMC ·
Engineering
level GUI |
Drive the FSM in incremental steps (TBD)
towards its limits noting the point at which the offload to the TCS occurs.
Verify that FSM does not exceed safe operating limits. Note: A means of
independently monitoring the FSM surface tip/tilt is desirable for this test. |
|
|
|
|
111 |
Verify that FSM
offsets are off-loadable to the TCS. |
·
OMC ·
Engineering
level GUI |
This test should be
combined with test ID 110. |
|
|
|
|
112 |
Verify that FSM
frequency response is > 250 Hz (-3dB point) |
·
OMC ·
Engineering
level GUI ·
Collimator and
position-sensing detector to measure FSM surface tilt. |
1.
Set up
collimator and position-sensing detector (PSD) to measure FSM surface tilt. 2.
Apply small
amplitude (< 50mrad surface tilt)
sinusoidal oscillation to FSM progressing from low to higher frequencies.
Record FSM tip/tilt amplitude as measured with PSD. Exercise caution if
resonance starts to occur. 3.
Determine –3 dB
frequency. |
|
|
Repeat of tests
performed at the ATC. Test subject to equipment availability. |
|
113 |
Verify that the FSM
open-loop jitter is < 48 nrad (0.01 arcsec) rms in WHT object space for
either axis. |
·
OMC ·
SBIG camera ·
NCU ·
Engineering
level GUI |
1.
Install and
align the NCU and OMC. 2.
Flatten the DM
or install the dummy DM. 3.
Install the
SBIG camera at the OSP to view the NCU on-axis DL point source. 4.
With the FSM
power off, measure the point spread function (PSF) using the SBIG. 5.
Measure the PSF
again with the FSM power on in open loop. 6.
Determine the
increase (if any) in the PSF width in both axes with the power on and convert to angle in WHT object space
using the plate scale. |
|
|
|
|
131 |
OMC and WFS must
register repeatably to each other with < 50 mm
accuracy in all 3 axes. |
·
OMC ·
NCU ·
WFS ·
Engineering
level GUI. |
This test is
identical to WFS test ID 39 and it should not be repeated. |
|
|
|
|
147 |
NCU provides on-axis
point source which is full-aperture diffraction limited (DL) at visible
wavelengths. |
·
NCU ·
SBIG camera |
1.
Set up the SBIG
camera to view the NCU on-axis point source. 2.
Record and
analyse the PSF. |
|
|
|
|
150 |
Verify that the NCU
point source radiant intensity conforms to OMC WPD Table 2. |
·
OMC ·
NCU ·
WFS ·
Engineering
level GUI. |
1.
Flatten DM and
set FSM to midrange. 2.
Select WFS
lenslet 1, 4 x 4 pixel mode and ADC to zero dispersion. 3.
Move WFS
pickoff to acquire and centre NCU on-axis point source image in WFS field of
view. 4.
Determine
photons received per subaparture in 5 msec integration time and convert to
radiant intensity from source. 5.
Extrapolate to
infrared from these test results. |
|
|
More detailed
information to be provided. |
|
153 |
Verify that the NCU
point source tip/tilt injection amplitude is variable up to 2.6 arcsec |
·
OMC ·
NCU ·
WFS ·
Engineering
level GUI. |
1.
Select NCU on-axis
point source, i.e. no FP mask. 2.
Flatten DM and
set FSM to midrange. 3.
Select WFS
doublet and set ADC dispersion to zero. 4.
Move WFS
pickoff to acquire point source and centre in WFS FOV. 5.
Set NCU tip/tilt mirror to 2.6 arcsec amplitude at
< 10Hz and determine amplitude seen by WFS. |
|
|
|
|
154 |
Verify that the NCU
point source tip/tilt injection frequency is controllable from 0.1 to 150 Hz. |
·
OMC ·
NCU ·
WFS ·
Engineering
level GUI. |
Depending on maximum
frame rate achieved with WFS, this test may be carried out as a continuation
of ID 153. Spot motion will be poorly sampled at 150 Hz. Alternative approach
is to use NCU He-Ne laser and a position-sensing detector (as used at the
ATC). |
|
|
|
|
157 |
NCU point source
spectral distribution shall correspond to G0 to K0 spectral type. |
·
NCU ·
ATC photometer
or equivalent calibrated detector. ·
Spectral
filters (ideally 0.1 mm bandwidth over 0.5 to
1.0 mm) |
Measure the spectrum
of the direct output of the NCU using the photometer and filters. |
|
|
Test subject to
availability of suitable filters and detector. |
|
165 |
Verify that the
extended source radiance conforms to Table 3 of OMC WPD. |
·
NCU ·
Engineering
level GUI ·
ATC photometer |
Note that the solid
angle of the extended source must be determined (or assumed from the optical
design). The photometer measures irradiance and the solid angle is needed to
determine radiance, i.e. W/cm2/ster. As the ATC photometer only
operates over 0.5 to 1.0 mm one may have to use an
IR camera to complete the measurement. |
|
|
Test subject to
equipment availability. |
|
167 |
Verify that NCU
extended source uniformity is < 0.5 % over 10 mm diameter. |
·
NCU ·
Engineering
level GUI ·
ATC photometer
with 1mm dia mask. ·
x-y stage with
>10 mm travel for photometer head |
1.
Install mask on
photometer head and mount assembly at NCU output. 2.
Set up NCU to
provide extended source. 3.
Measure
uniformity of illumination across at least two diameters moving in <
1 mm increments. |
|
|
Difficult to make
reliable measuremen-ts to 0.5 %. |
|
168 |
Verify that a NCU
He-Ne laser source is available for on-axis alignment. |
·
NCU ·
OMC ·
Engineering
level GUI |
1.
Install He-Ne
laser in NCU 2.
Turn on the
laser and verify that beam properly illuminates the DM. |
|
|
|
|
186 |
Provision must be
made to calibrate non-common path errors between science path and the WFS. |
·
NCU ·
OMC ·
WFS ·
Engineering
level GUI ·
SBIG camera |
Procedure to be
added later to cover methods developed by Durham. |
|
|
|
|
199 |
Verify fit and
function of spare components, if any. |
·
Spare
components |
Any components to be
identified by the ATC. |
|
|
|
|
200 |
Verify the
mechanical fit of the OMC/NCU
components in their shipping containers. |
·
OMC ·
NCU ·
Shipping
containers |
Pack and inspect. |
|
|
|
|
202 |
Measure the
open-loop transfer function of the NCU tip/tilt mirror. |
·
OMC ·
NCU ·
SBIG camera ·
Engineering
level GUI. |
This test should be
performed after ID 154, i.e. independent verification of the frequency range
is required. The approach assumes that a sufficiently sensitive, high
bandwidth position-sensing detector is not available. 1.
Flatten DM and
set the FSM to midrange. Set up the SBIG on axis at the science port. 2.
Turn on the
on-axis point source with the tip/tilt mirror stationary. Record the image
and determine the PSF width (baseline). 3.
Turn on the
tip/tilt mirror (amplitude TBD) at 1 Hz. 4.
Integrate with
SBIG for > 30 sec. Determine width of blurred PSF and subtract baseline
width to arrive at measured amplitude of oscillation. 5.
Repeat at 10 Hz
intervals to 150 Hz. Shorter integration times may be used at the higher
frequencies. 6.
Derive transfer
function from ratio of commanded motion to measured motion as a function of
mirror frequency. |
|
|
Test approach is
subject to review. Phase information is not obtained. |