Keck Interferometer Auto-Alignment System

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Nov 14, 2013 (3 years and 11 months ago)

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KECK
INTERFEROMETER
Keck Interferometer
Auto-Alignment System
Leonard J. Reder
Leonard.J.Reder@jpl.nasa.gov
818-354-3639
Jet Propulsion Laboratory
Pasadena, California
20 Nov. 2002Keck Interferometer Autoaligner2
Contributors

At JPL: A. Booth, M. Colavita, E. Deems,
E. Hovland, R. Johnson, R. Ligon, J. Moore,
D. Palmer, R. Smythe, A. Tumminello,
G. van Belle

At Keck Observatory: A. Rudeen, T.
Saloga, K. Tsubota
20 Nov. 2002Keck Interferometer Autoaligner3
Keck Interferometer Update

2 Keck 10m telescopes with full adaptive optics (AO).

Wavelengths 1.2 um to 10 um (AO operates in visible).

Science:
nulling, differential phase, astrometry,
imaging.

First fringes with Keck Telescopes March, 2001.
20 Nov. 2002Keck Interferometer Autoaligner4
First Fringes

Initial fringes using siderostats were obtained on Feb. 22,
2001.

Checked out hardware to be used with
Kecks
on next run.

Two 50-cm siderostats feeding fixed 40 cm telescopes (essentially
the same as the Palomar Testbed Interferometer front-end optics).

EPICS 3.14 alpha SNL sequencer used for sidereal delay
line target generation through 2001.
Enclosures

First fringes using two large
Kecks
March 12-14, 2001
(3 1/2-nights)
20 Nov. 2002Keck Interferometer Autoaligner5
What I will talk about

Interferometer Major Components

Automatic Alignment Process
-
Sequencers -
EPICS State Notation Language (SNL)
--
Beam Train Alignment Sequencer (btSeq)
--
Internal Instrument Alignment Sequencer (iiSeq)
-
Optical alignment control user interface (aligner.tcl)
--
Manual and automatic

Sensors/Actuators/Targets and EPICS
-
Device Support and Drivers
-
Use of existing EPICS components (Records, Device
Support and Drivers)
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Fast
delay
lines
Long delay lines
Beam
Injection
and
Switching
Switch-
yard
Imaging
and nulling
combiners
Fringe trackers
Angle trackers
Auto-aligner
Keck 1
CCD
Optical Path Through the Basement
Keck 2
20 Nov. 2002Keck Interferometer Autoaligner7
Optics and Control Layout for First Fringes
k5,m10
k6,m10
k6,m11
k5,m11
k1,m11
k2,m11
k1,m14p
k2,m14p
k1,m20p
k2,m20p
k1,m24p
k2,m24p
k1,m
21p
k2,m21p
k
2,
ccdp
k1,ccdp
FDL0
FDL1
KAT
p
k0,dcrp
k2,dcrp
k1,dcrp
bc1,m23f
bc1,m23b
bc1,bfw
bc1,f
fw
bc1,m25
bc1,stim,wlm
bc
1,
stim,bslm
Bore Sight
White Light
bc1,stim,wfw
bc1,stim,wlint
bc1,stim,bs
lint
k1,m10
k2,m10
Sid 2
Keck 1
Keck 2
Sid 1
Optics Layout for motion cont
rol for fir
s
t fringes
v1.7, 6/26/01,
A
.J
.Booth
LDL1
LDL0
k1,m9
k2,m9
FA
TCAT1
ft1,fw
f
t1,prsm
ft1,tt1
ft1,tt2
k1,shp
k2,shp
bc1,stim, bslsh
kat,sh
ftf
bs
bc1,sh1
bc1,sh2
bc1, m2
bc
1
,
m1
bc1,stim,wlsh
ft1,focus
sy,ccaln
sy,ccf
ts
bc1,stim,inp
CT met
k1,shct
k2
,shct
k2,stop
k1,stop
k2,shkat
k1,shkat

AA Sequencers:
-6
B
e
a
m
T
r
a
i
n
-
4 Internal

Sensors:
-2
C
.
T
.
-
4 Cameras

Stimuli Targets:
-
White Light
-
Laser Boresite
-
12 LEDs

Actuators:
-
20 Newport 850G
-
26 Pico Motors
-
16 Shutters
-
Other Misc.
20 Nov. 2002Keck Interferometer Autoaligner8
Interferometer Major Components
Beam Transport Optics
(Coude Train)
Keck 1 FM
Fringe Tracker (FATCAT)
Fast Delay Lines (FDL)
Angle Tracker (KAT)
Long Delay Lines (LDL)
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Keck Interferometer Software
CORB
A
JPL RTC Toolkit
“Fast Servo Control”
-Fringe Tracking
-Delay Lines
-Tip Tilt
JPL/Keck EPICS
“Auto-Alignment”
-Motion Control
-Sensors/Targets
Keck EPICS
“Telescope S/W”
-
Sequencer
User Interface Scripts
Optical Alignment
Tool
(aligner.tcl)
Misc. dm and dm2k
panels.
Sequencer
Observing Tool
(seq.tcl)
Chann
el
Access
JPL RTC JAVA
Engineering GUI
Channel
Access
20 Nov. 2002Keck Interferometer Autoaligner10
Automatic Alignment Approach
1.
Align “backwards” from detector to telescope.
2.
Threading optical axis from instrument internal combiner
out through beam train to optical telescope.
Front view:
Mirror surface
and LED target
in front.

Use camera at back end of
system.

Use LEDs mounted on swing arm
and positioned in front of mirror as
alignment targets.

Illuminate
LEDs, and align prior
mirror in beam train.

Repeat from inside instrument up
to telescope to thread beam along
optical axis.
20 Nov. 2002Keck Interferometer Autoaligner11
EPICS Alignment Control of Major Components
Long Delay Lines Sled
Beam Transport Optic
As Seen from Coude
Tunnel
Beam Transport Optic

Beam Transport Optics (Coude
Train) and Long Delay Lines (LDL)
auto-alignment via SNL sequencer implementation (btSeq).
20 Nov. 2002Keck Interferometer Autoaligner12
EPICS Alignment Control of Major Components
Opened Fringe Camera
Fiber-fed laser metrology
Dichroic Optic

Fringe Tracker (FATCAT)

PZTs driven by JPL custom device support for alignment.

Focus and filter wheel control, white light stimulus adjustment, etc.

Angle Tracker (KAT) and Constant Term Metrology SNL seq. alignment
20 Nov. 2002Keck Interferometer Autoaligner13
EPICS Automatic Alignment Sequencers

Implemented in VxWorks using SNL.

One instance of sequencer per mirror to align.

Internal Instrument Alignment Sequencer (iiSeq)

Alignment of back end sensor components
(KAT, FATCAT, CCD).

Auto-align constant term metrology.

Beam Train Alignment Sequencer (btSeq)

Large transport optic mirrors.

LDLs and Coude Train.
20 Nov. 2002Keck Interferometer Autoaligner14
Autoaligner Camera System
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Frame Grabber/Centroiding
genSub
Image
Grab/Centroid
forward link
triggered from
sequencer or
periodic rate
scan.
Frame
count
INP link to
Select
Snapper 24
XCEN,
YCEN
coordinate
of
alignment
target.

DataCell
Snapper 24 PLC frame grabber used with modified version of
driver written by Miroslaw Dach
(dach@psi.ch) at the Paul
Schere Institure.

Device support links driver and Image Record written by Ned Arnold
(nda@aps.anl.gov) LANL. Image Record is glue between EPICS IOC and
genSub
record.

genSub
record used to wrap alignment target centroid estimation algorithm.
20 Nov. 2002Keck Interferometer Autoaligner16
Actuated Optics
Transport Optic w/850G
Dichroic
Optic w/Picomotors

Common actuators used: two kinds throughout system.

Beam Train Transport Optic driven by Newport 850G DC
servo long travel actuators.

Piezoelectric New Focus Picomotors
used on smaller optic.
20 Nov. 2002Keck Interferometer Autoaligner17
Actuated LED Targets
Retracted
In position and illuminated

AA Targets position and illuminate with a high degree of
repeatable motion: 0.25mm

Limit switch feedback state of target to EPICS device support.
20 Nov. 2002Keck Interferometer Autoaligner18
EPICS Device Support and Drivers

Datacell Snapper 24 Frame Grabber image record support.

Delta Tau
Turbo PMAC device support and motion
control sequencing used on Keck AO bench is used for
beam train transport optic positioning.

Originally written by Thomas Coleman, ANL

Updated by Kevin Tsubota and Paul Stomski, Keck

Industry Pack device drivers support utilizing Andrew
Johnson’s Industry Pack Driver Software (drvIpac).

Acromag IP480, IP230, IP330 modules

Greenspring IP-Digital24, IP-Driver40 modules

Generic device support for bi, bo, ao, ai,
longin, longout

JPL specific device support implemented.

Picomotors, cryo focus motor, laser attenuator, etc.
20 Nov. 2002Keck Interferometer Autoaligner19
Automatic and Manual Optical Alignment
User Interface TCL Application (aligner.tcl)
Alignment
Position
Status
Actuator
Status
AA
Sequencer
Monitors &
Controls
AA Mirror
Select
Text Status
Sensor
Select
Alignment Vector
& AA Camera Image
20 Nov. 2002Keck Interferometer Autoaligner20
Summary

KI is taking “shared risk” science data (since June).

Automatically aligning parts of interferometer.

Angle Tracke
r (KAT).

CT Metrology.

Fringe Tracker (FATCAT).

Beam Train Mirrors.

Refinement of Frame Grabbing Technology and
Centroiding
for better beam train auto-alignment is needed
(presently ~ 1.5 pixels, requirement 0.1 pixels).

A top level sequencer to orchestrate all alignment is next
major development effort.

More info about Keck Interferometer go to web site:
http://planetquest.jpl.nasa.gov.

Device support codes available from
reder@huey.jpl.nasa.gov.
20 Nov. 2002Keck Interferometer Autoaligner21
W. M. Keck Observatory: Feb. 2002