Transcript Slide 1

Mauna Kea Laser Guide Star
Technical Working Group
Working Group Meeting
November 22, 2005
MK LGS TWG
Agenda
2:00 Welcome & Introductions. Review agenda.
2:10 LGS AO System Status & Schedules
– Purpose: Informational
2:15 Collisions
– Purpose: Reduction of frequency & impact of collisions
3:00 Aircraft safety & Laser Clearinghouse
– Purpose: Reduction of overhead (summit aircraft safety
system, improved LC interaction)
3:25 Mauna Kea Laser Policy
– Purpose: Update policy if appropriate
3:40 Other issues?
3:50 Next steps & action items
– Purpose: Clear path forward
PW
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MK LGS TWG
Welcome & Introductions
MK LGS TWG:
–
–
–
–
–
Doug Simons (Gemini)
Hideki Takami (Subaru)
Christian Veillet (CFHT)
Richard Wainscoat (UH)
Peter Wizinowich (Keck)
Other Participants:
– Gemini: Mathieu Bec, Celine d’Orgeville, Francois Rigaut
– Keck: Randy Campbell, David Le Mignant, Doug Summers
– Subaru: Yutaka Hayano
PW
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MK LGS TWG
LGS AO System Status & Schedules
Keck
Gemini
Subaru
PW
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MK LGS TWG
Keck LGS AO:
The top priority for Keck Science
Keck II: Laser propagation summary and plans
Year
2002
03
04
05
06
07
#nights
2
16
17
47
~100
~140
Operational model by 07A:1 OA at HQ to operate LGS & 1 at summit
to monitor laser & safety systems in addition to telescope
Keck I
– 20W mode locked CW laser contracted with CTI
– LGS AO system design in FY06. Implementation into FY08.
DLM
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MK LGS TWG
Gemini LGS AO
GN: 12W laser and Altair
– LGS first light on May 2, 05
– 2.5 nights for LGSF technical commissioning (May 05) including star wars test w/
Keck + 16 nights for Altair LGS technical commissioning (June, July, Aug, Sep, Nov
05)
– Science commissioning on hold until Feb 06 LLT M1 re-polished; 10-12 nights
planned in 2006A
– Commissioning of instruments in LGS mode: NIFS, etc.
Operational model for 06B:1 laser tech at summit to prep laser in the
afternoon and monitor laser & safety systems for first part of the night, remote
support from home/HP as needed
GS: 50W laser and MCAO
– 50W mode locked CW laser contracted with CTI, delivery in Jan 07
– MCAO I&T through 2006
– LGS first light in 2007A, tech + science commissioning by end of 2007B
Cd’O
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MK LGS TWG
Subaru LGSAO
188 element curvature sensor AO
4W sum frequency laser collaborated with RIKEN at
Nasmyth focus (10W upgrade is planned)
2005/10
2006/1
2006/8
2006/12
2007/3
HT
Laser projection demo in Japan
NGS laboratory closed loop
Laser & LLT deliver to Hilo
NGS first light
First projection of laser to the sky
LGS first light
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MK LGS TWG
LAYOUT of Subaru LGSAO
Instruments
IRCS, HiCIAO
HT
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MK LGS TWG
Collisions
Collision frequency & impact
– Keck statistics
– Is this consistent with predictions?
Rayleigh scatter impact
– Subaru measurement of Keck beam
– UH image
– Impact of cirrus
Impact on instruments
– CFHT, Gemini, Keck, Subaru, UH
URLs
– How are they set at each Observatory?
– Can this be done better
LTCS
– Gemini/Keck test
– What should be improved
Ideas for reducing collision frequency & impact
PW
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MK LGS TWG
Collision Frequency & Impact
Keck statistics
– Average of 18 min time lost to collisions per night
– Time altered considerably more: broken dither pattern, switching
to lower priority object, taking more calibrations than necessary, etc.
One Year, 37 nights, of LGSAO Science at Keck
Notes:
• Collide with all telescopes (except UKIRT?)
• Don’t collide with K1 more frequently (likely
because no impact flag set whenever
possible)
• Some recent collisions apparently during
slewing by other telescopes (UH & Subaru)
• Had collisions while aligning laser at zenith
when CFHT & Subaru weren’t tracking
(collecting twilight flats)
RC
Weather
16.2%
Overheads
(inst+tel+ao)
37.3%
Laser Traffic
Control
1.3%
Spotters
0.2%
Space Cmd
0.7%
Laser faults
11.9%
AO faults
2.8%
Open Shutter
Science Time
w/LGSAO
27.4%
Other Faults
(inst+tel)
3.2%
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MK LGS TWG
Collision Frequency & Impact
Gemini preliminary data
– Data not automatically collected yet
– Based on May, June, July, Aug, Sep and Nov 2005 engineering
runs (lots of zenith propagation, no “real science” and no queue
yet): 0-3 collisions/night (none in 2-night Nov run!?)
RC
Run (2005)
May
June
July
Aug
Sep
Nov
#nights
2
4
6
3
3
2
Predicted
collisions
>2 ?
2
1xCFHT
Effective
collisions
2
2
0
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MK LGS TWG
Scatter Impact Measurement with
Keck II and Subaru (Hayano et al. 2003)
Keck II was pointed to SAO99809 on
December 24, 2001. (El ~ 70 - 80).
Subaru was pointed to fixed direction.
(El = 45, 60).
Scattered light was measured by
APDs of Subaru AO WFS.
Three collisions were observed.
YH
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MK LGS TWG
Scatter Impact Measurement with
Keck II and Subaru (Hayano et al. 2003)
Pupil plane measurement for finite FOV q
(e.g. 1 arcsec).
If (d+L q) < D, pupil does not illuminate
fully. (Larger D, closer laser beam L).
Smaller telescope affected more.
– Sky background proportional to D2,
while laser beam scattered light
proportional to min(D2, D(d+L q)).
Imager with smaller pixel scale less
sensitive to laser beam scattering.
– Laser beam seems to be bright to
naked eye or a sky monitor camera.
YH
Focal plane measurement.
Laser beam scattered light completely defocused
with a size of (d+D)/L radian.
1 arcmin @ 30km, 0.5 degree @ 1km
19 arcsec @ 90km, (LGS size at focal plane)
If LGS magnitude is 10,
– 14mag/arcsec2 @ 80m (19x38 arcsec2)
13
2)
– 18.8mag/arcsec2 @1000m (19x231 arcsec
MK LGS TWG
Estimation of Scatter Impact
(Hayano et al. 2003)
Rayleigh scatter and Mie scatter model
YH
– Number density of molecule is derived from Hilo radio-sonde observation. (for Rayleigh)
– Aerosol distribution mode is estimated from AERONET database and particle counter
data at Subaru for Mie scatter evaluation. (Scale height of aerosol was ~ 3km. It was
class ~14000 at Mauna Kea.)
– Model calculation showed that the number of Rayleigh scattered photons was about 6
times as much as that of Mie scattered photons.
– Roughly speaking, the surface brightness of 17.5 mag/arcsec2 is comparable to the sky
brightness at about 15 degrees away from full moon.
– The impact is larger for smaller and nearer telescopes.
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MK LGS TWG
Rayleigh Scatter Impact from digital photograph
Factor 8 brighter than dark sky in R (2.2 magnitudes)
Factor 4 brighter than dark sky in V (1.5 magnitudes)
Dark sky:
R: 20.3 mag/(“)2
V: 21.1 mag/(“)2
RW
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MK LGS TWG
Rayleigh Scatter & Cirrus
Current Keck propagation criteria have been revised in
KAON 318
1. The laser must be shuttered if spotters detect an aircraft within 25º of
the beam.
2. The laser must be shuttered if thick clouds are present within 25º of the
beam, preventing approaching aircraft from being seen.
3. Our experience is that we have been able to propagate through thin
cirrus (& have productive LGSAO science nights). The spotters report
to the Observing Assistant (OA) on the passing of thin clouds that
could produce an increase in scattered light. The OA & LGSAO
operator monitor the scattered light using the WFS intensity display,
the acquisition camera and other available tools; if the amount of
scattered light is such that the laser return has decreased by more than a
factor 2 on the WFS (0.75 mag), the LGSAO operator & OA will close
the shutter.
DLM
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MK LGS TWG
Impact on Instruments - Keck
FOV °
(old)
FOV °
(new)
Science BW
μm
Guider
BW μm
ESI
0.133
0.189
0.3-1.0
HIRES
0.018
0.017
NIRC
0.228
PCS or SSC
AO/IF
Instrument
Guide Pos
Na
Impact
Rayleigh
Impact
0.5-0.9
150" off axis
Yes
Yes
0.3-1.0
0.5-0.9
on axis
Yes
Yes
0.156
1.0 - 4.0
0.5-0.9
250" off axis
Yes
Yes
0.25
0.025
0.5-0.9
n/a
No
No
0.25
0.022
1.6 - 12.0
0.5-0.9
Yes
No
0.381
0.3-1.0
0.5-0.9
Yes
Yes
DEIMOS
on axis
LRIS
0.313
0.189
0.3-1.0
0.5-0.9
300" off axis
Yes
Yes
NIRSPEC
0.055
0.085
1.0 - 5.0
0.5-0.9
on axis
Yes
Yes
AO/NIRC2
0.033
0.022
1.0 - 5.0
0.5-0.9
on axis
Yes
No
AO/NIRSPEC
0.033
0.022
1.0 - 2.5
0.5-0.9
on axis
Yes
No
AO/OSIRIS
0.033
0.022
1.0 - 2.5
0.5-0.9
on axis
Yes
No
Keck I, Keck II, Both
PW
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MK LGS TWG
Impact on Instruments - Gemini
Instrument or
Wavefront Sensor
Science Channel
Wavelength Range
(µm)
Science Channel FOV
(dia. - arcmin)
Wavefront Sensor
Wavelength Range
(µm)
Wavefront Sensor
Patrol Fielda
(dia. - arcmin)
A&G - P1
N/A
N/A
0.4-1.0
14
A&G - P2
N/A
N/A
0.4-1.0
14
HRWFS
N/A
N/A
0.4-1.0
<0.05
Acq. Cam.
N/A
N/A
0.4-1.0
2
NIRI
1-5
3 (0.3b)
1-2.5
3 (2b)
GMOS
0.4-1.0
5.5
0.4-1.0
3.5x4.2c
MICHELLE
8-25
0.3
N/A
N/A
NIFS
1-2.5
0.05b
1-2.5
3 (2b)
ALTAIR
N/A
N/A
0.4-1.0
2 (<0.05d)
All wavefront sensors use patrol fields centered on telescope’s field except GMOS
b) When used in conjunction with ALTAIR
c) Centered 2.5 arcmin off-axis
d) LGS wavefront sensor
18
DS
a)
MK LGS TWG
Impact on Instruments - CFHT
"Prime" or "MP"
"Cass"
"I.R."
"Coude"
anything else
fov = 1.1667
fov = 0.8
fov = 1.1667
fov = 0.8
fov = 1.1667
This is actually old information at a time when the TCS could
not recognize the instruments. It needs updating with the
current instrumentation and better numbers for the FOV.
"Prime" should be the only one at 1.1667!
"I.R" (the new WIRCam) is much smaller, and there should not
be "anything else"!
CV
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MK LGS TWG
Impact on Instruments - Subaru
Instrument
Focus
FOV
wavelength
(um)
Guider
search area*
SuprimeCam
Prime
34’x27’
B-z’
58’ dia.
FMOS ( 2006~)
Prime
30’ dia.
0.9-1.8
43’ dia.
FOCAS
Cs
6’ dia.
0.33-1.0
10’ dia.
MOIRCS
Cs
4’x7’
1.17-2.30
10’ dia.
CISCO
Nas IR
108”x108”
0.88-2.51
8.8’ dia.
HDS
Nas Opt
60” Slit viewer 0.31-0.94
6’ dia.
IRCS (2005/12~)
Nas IR
48”x48”
0.92-4.8
8.8’ dia.
COMICS
Cs
42''x32''
8.0-25.5
10’ dia.
CIAO
Cs
22”x22”
J-M’
10’ dia.
* They are the upper limit of the search area,
HT
20
MK LGS TWG
Impact on Instruments - UH 2.2-m
Tek 2048:
Optic CCD:
8k CCD:
Offset Guider:
ULBCAM:
WFGS2:
SNIFS:
RW
FOV 0.18 deg 0.4-1.0 microns
FOV 0.22 deg 0.4-1.0 microns
FOV 0.78 deg 0.4-1.0 microns
FOV 0.83 deg 0.4-1.0 microns
FOV 0.4 deg 1.0-1.8 microns (no impact)
FOV 0.26 deg 0.4-1.0 microns
FOV 0.002 deg 0.3-1.0 microns
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MK LGS TWG
Impact on Instruments - IRTF
Guider (on axis): FOV 0.008 deg 0.4-1.0 microns
RW
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MK LGS TWG
Standard URL
Includes the following fields (as per the LTCS_URL_Interface_Specification
dated Feb 7, 2002):
–
–
–
–
–
–
–
–
–
–
DS
Timestamp1
Telescope
RA
DEC
Equinox
FOV
Laser_impacted
Laser_state
log_data
Timestamp2
- local time (time of URL update)
- telescope name
- telescope right ascension (hrs)
- telescope declination (deg)
- equinox and epoch of coordinates
- diameter of field of view
- telescope is (or is not) laser sensitive
- telescope is (or is not) projecting a laser
- flag to enable/disable logging of pointing data
- local time (time of URL update)
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MK LGS TWG
URL setup – KECK1 & KECK2
URL updates accomplished automatically via
programmatic control (Java/solaris):
– FOV values determined via current instrument lookup
– RA/DEC/Equinox set from TCS with az/el/frame conversion
to RA/DEC/Eq (as needed)
– LASER_IMPACT set from combination of domeshutter
state, dome track state, and telescope track state.
– LASER_STATE set from laser fast-shutter state (with
capability to override)
Program runs in near-real time; as fast as keyword
layer parameter changes occur, notification & rewrite
of the URL file occurs.
DS
24
MK LGS TWG
URL setup – Subaru
URL address
http://www.naoj.hawaii.edu:8011/cgi-bin/ltcs.cgi
http://www2.naoj.hawaii.edu:8011/cgi-bin/ltcs.cgi (backup)
http://www3.naoj.hawaii.edu:8011/cgi-bin/ltcs.cgi (backup)
Update interval of URL page is changed by executing some
commands through “at” table from 15 seconds to 1 second
during LGS observation.
– FOV is set to be 1 degree for Prime Focus Camera and 8 arcmin
(FOV of AG roughly) for other instruments. (tentative)
– RA/DEC/EQUINOX information is gotten from TCS.
– TIMESTAMP is gotten from NTP server at Subaru.
– Information collected from the telescope telemetry server almost in
real time.
– LASER_IMPACT sets if RA/Dec changes slower than 0.1 deg/sec.
(tentative patch on Nov. 10, 2005)
25
MK LGS TWG
URL setup – Subaru
Prof. Ryu Ogasawara still manages the URL setup,
even after he moved to ALMA project. (Handover is
to be scheduled.)
Are we clear on who the URL contacts are at each
Observatory?
– Prof. Ryu Ogasawara ([email protected])
Handover is to be scheduled soon.
– Yutaka Hayano ([email protected])
How is laser propagation information supplied to
nighttime operations personnel?
– The announcement of laser projection is circulated the
mailing list of operation center including night operators and
support astronomers.
26
MK LGS TWG
URL setup
CFHT
Gemini (128.171.88.53)
UH
IRTF
Are we clear on who the URL contacts are at each
Observatory?
How is laser propagation information supplied to
nighttime operations personnel?
DS
27
MK LGS TWG
LTCS
Current LTCS version (1st Generation):
– Limited testing with other telescopes
– Limited resources for development & testing (LTCS & URLs)
Installations & version consistency between Keck, Gemini, Subaru
– URL Site issues:
Some manual (vs. TCS/programmatic control) setting of parameters
RA/DEC precision & slew issues being worked with Subaru
Slewing with Laser_impacted=YES (most observatories)
– Re-development of LTCS by Subaru.
2nd generation LTCS SW install & testing:
–
–
–
–
–
–
DS
Consistency with La Palma SW baseline (Joint dev, more functionality)
New priority-based rules (backward compatible to MK config)
Laser/Laser “first on target” wins algorithm included
New tools (simulation/Query)
Slew filtering (auto-detection) & notification
Some improvements over 1st generation issues above, but also some
similar issues (more coordination for version control & bug fixes, etc.)
28
MK LGS TWG
LTCS Positional Errors & URL polling
Positional Error:
– Current version uses FOV cone extension (currently 10% for all
telescopes in MK config) as error term.
– 2nd generation LTCS adds survey inaccuracy parameter to base
telescope position (effectively an aperture increase)
URL polling rates:
–
–
–
–
–
–
Kecks:
Gemini:
UH2.2:
CFHT:
Subaru:
IRTF:
1 sec
1 sec
1 sec
3 sec
3 sec
5 sec
STALE processing for all sites is currently configured for 120
seconds.
DS
29
MK LGS TWG
Other LTCS Issues
LTCS priority rules: As laser investments increase to 4 lasers
on MK, should we consider migration to a La Palma type
collision priority rules model (first-on-target wins)?
– All telecopes have access to Query/planning tools for target
selections.
– Favorable query response indicates ability to stay locked on target
throughout observation; unfavorable response indicates collision
times (for planning when to shutter science camera and/or laser
depending on who has priority).
– Maximizes fairness & observing efficiency; reduces shutter time
– Ability to configure fully independent priority rules; can have ELT
(for instance) have priority over all telescopes or establish custom
priority rules for each telescope/laser combination.
DS
30
MK LGS TWG
Ideas for Reducing Collision Frequency & Impact
Better collision predictions
No impact while slewing
More careful setting of URL
– Instrument fov
– Laser impacted flag
– Observer program taken into account?
Distinction between Na & Rayleigh scatter impact
Different criteria for shuttering
DS
31
MK LGS TWG
Aircraft & Satellite Safety
FAA renewal & issues
Spotters
Boresight camera systems (Gemini, Keck)
Gemini wide field camera system
Mosaic radar?
Collaboration with other groups (JPL, Palomar)?
Laser Clearinghouse
How do we want to collaborate?
PW
32
MK LGS TWG
FAA Renewal & Issues
Keck proposal renewed till Dec. 06
Keck’s experience
– Requested collection and compilation of spotters data (aircraft and
weather) is a cumbersome process, yet interesting for statistics on
laser propagation & operations.
– 2 aircraft incidences since 2001 (and we shuttered per procedure)
– 2006 renewal process: 1 month FTE, benefited from previous
renewals
– Would like to review proposal process w/ other observatories.
– Our FAA contact: “doesn’t have a lot of faith in oxygen-deprived
observers looking in a star-filled sky for aircraft”. Yet, understands
the expense to the observatory, and the logistics involved.
– FAA actually recommends working on implementing the JPL
system that is currently being reviewed.
DLM
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MK LGS TWG
FAA Renewal & Issues
Gemini’s experience
– Current permission (our first; not a renewal) valid until April Fools’
Day 2006.
– With our first application, the FAA (Larry Tonish) sent us a fairly
routine set of questions, which we answered, after consulting with
Jason Chin (thank you, Jason).
– They wanted to ensure that our spotters were going to be provided
with protection from the weather and hypoxia.
– After answering the questions they granted us permission for a
period of one year.
– We are in the midst of a process to obtain permission to operate
lasers at Gemini South. The Chilean FAA equivalent has been very
cooperative.
– Following Keck’s model to collect statistical information on spotter
data.
KB/BG
34
MK LGS TWG
Spotters
Logistics for managing aircraft spotting is resource intensive
–
–
–
–
–
Managing spotters pool (hiring, training, schedule)
Transportation & safety
Procedures and spotters logs
Meals and equipment
Time sheets and payment
Keck’s experience:
– Two lead spotters responsible for transportation, training and
coordination.
– Spotting procedures reviewed and re-enforced in Nov.2005
– Whole process is problematic because we are dealing w/ part-time
outside resources.
Keck use of aircraft spotters
– http://www2.keck.hawaii.edu/optics/lgsao/docs/kaon360.pdf
DLM
35
MK LGS TWG
Spotters
Keck has built a base of spotters from an outside resource
– Gemini uses the same pool of spotters
– This pool of spotters must originate from the Keck because of specific background
checks that is mandatory in Keck’s HR policy. Gemini does not have the same
requirements. To keep recruitment of the spotters consistent, Keck HR has agreed to
manage the initial recruitment of the spotters from the outside resource.
Gemini’s experience:
– Before assigning a spotter to a Gemini run:
They are given a safety orientation from our safety officer.
They are given a general orientation for our laser program from AO program manager(s).
– Gemini prefers to schedule the spotters for each run internally. The Engineering
Admin Asst calls available spotters from the pool (from outside resource) for
assignments.
– Two lead spotters were recently hired to the Gemini staff and are assigned to every
run with a team of 3 additional spotters from the outside resource. The leads are
responsible for transportation and direction of the spotter team.
– The scheduling is not a big issue and is not time consuming. Most of the time,
spotters call to request scheduling. Using the outside resource is an not an ideal
situation. Our experience with the outside resource has not been a completely
positive one.
KB
36
MK LGS TWG
Boresight Camera Systems
Gemini
– ~15 fov Merlin - Indigo IR camera
– Continuous imaging & real time analysis
– Aircraft detection signal sent to LIS/GIS to activate safety
shutter
Keck
– 10 fov Amber IR camera
– Aircraft detection automatically closes fast shutter through
PLC within 1/30th of a second
– Can trigger on moon & can be overridden
PW
37
MK LGS TWG
Gemini Wide Field Camera System
Status
–
–
–
–
–
Software demonstrated
Camera mounted on SMA roof
Camera damaged by sunlight
Enclosure dome inadequate - too much scattered moonlight
No work on this for several months
Plans?
– Fix the current problems
Daytime shutter, new or modified camera enclosure, …
– Continue with integration and testing
– Continue collaborations
Cd’O
38
MK LGS TWG
Mosaic Radar
History
– 07/91 – Boeing & FAA agreement for Haleakala completed
– 11/99 – AFRL/Boeing development effort begins
– 05/01 – SW & HW integration complete; Boeing authorized from
FAA to provide UH with data
– 08/02 - Maui AF contingent tours MK, fails to break through
political issues related to technical transfer of info; correspondence
essentially stops.
Outstanding Political Issues:
– AF/Boeing/FAA MOA/MOUs needed before docs & technical info
can be provided/discussed in detail.
– Access to FAA data may be sensitive to international institutions
– FAA Certification for MK system (regardless of technical approach)
Existing System Technical Issues:
– Blind spots, multi-target correlation, simple azimuth wedge
avoidance cone, manual laser position input, shutter control
integration, HW & SW constraints, MK data access method.
DS
39
MK LGS TWG
Collaboration with other Groups?
JPL
– Keith Wilson (JPL Optical Communications Group)
attempting to establish a consortium of interested parties to
work with FAA on navigable air space safety solutions
Next step: Telecon strategy session
– Table Mountain system for day & nighttime propagation
2 boresighted LWIR cameras for low flying aircraft
Radar beam to detect high flying aircraft
Exploring FAA radar interface display system. Next step: fund
prototype development
Palomar
Cd’O
40
MK LGS TWG
Laser Clearinghouse
Keck’s Experience
–
–
–
–
–
Observer submit target list using web interface 3 days in advance
Still faxing target list and receiving approval fax
Never got any closures on target list
Lost ~4 hours in 2005 due to sudden call for “space events”
Received same-day approval for special requests: GRBs and
human error on main targets.
Issues
– Still lots of coordination with observers and US SC: effort level is
~5 hours per observing proposal for reliable operations.
– Could it be more automated (approval email could work)
DLM
41
MK LGS TWG
Laser Clearinghouse
Gemini’s Experience
–We fax the target list and receive approvals by fax or email. During our
November run, we requested approvals to be emailed to a group of
people. We received an email both days of our run indicating no closures.
–Never received any closures on target lists.
–Received same-day approval for special requests: Adding new targets or
changing targets.
Issues
–Coordination with observers and US SC runs pretty smoothly.
–A more automated way of submitting for approvals would be ideal.
Submit by email or by web interface.
KB
42
MK LGS TWG
Aircraft & Satellite Safety: Collaboration
How do we want to collaborate?
PW
43
MK LGS TWG
Mauna Kea Laser Policy
Policy
Keck Policies
Lasers at different wavelengths
Any reason to review policy?
– Weather
PW
44
MK LGS TWG
Mauna Kea Laser Policy
The following policy statement was approved at the Sept/97, Mauna Kea Directors’ meeting.
“The use of sodium D wavelength (589 nm) laser guide stars for astronomy is permitted on
Mauna Kea subject to the following conditions:
– No Observatory shall project a sodium laser beacon exceeding a power of 50 W.
Multiple beacons can be projected from a single Observatory as long as their total
power does not exceed 200 W. Laser beacons may not be projected at a zenith angle
greater than 70 degrees.
– Laser beacons must not interfere with observations being performed by other Mauna
Kea telescopes. Any Observatory pointing a laser beacon must, therefore, adhere to
the observing coordination guidelines approved by the Mauna Kea Directors.
– Any Observatory projecting a laser beacon must receive prior approval for their aircraft
system from the FAA. Only passive aircraft detection systems are permissible.
Written confirmation that conditions 1 to 3 have been met by an Observatory must be
provided to the IfA Director at least 30 days prior to the first projection of a laser beacon
from that Observatory.
Use of guide stars at alternate wavelengths will be permitted only after an evaluation of
their utility and impact, similar to that performed for sodium D wavelength lasers, is carried
out and is submitted to and approved by the Mauna Kea Directors.”
It was noted that for some Observatories that the use of laser beacons may require a
modification to the indemnification clause in the “Operating and Site Development
Agreement” between the Observatory and UH. It was also noted that a requirement may
need to be added in the future to the policy statement on the subject of satellite avoidance.
PW
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MK LGS TWG
Keck Laser Propagation Policies
Laser propagation restrictions & procedures
– http://www2.keck.hawaii.edu/optics/lgsao/docs/kaon269.pdf
Procedure for laser safety observing
– http://www2.keck.hawaii.edu/optics/lgsao/docs/kaon361.pdf
LGS AO weather cancellation policy
– http://www2.keck.hawaii.edu/optics/lgsao/docs/kaon318.pdf
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MK LGS TWG
Lasers at Different Wavelengths
CFHT VASAO (Visible All Sky AO Concept)
Feasibility study ongoing, to be
completed by end of 2006.
Could be operational around
2011-2012.
Based on:
– Pueo Hou: Pueo upgrade to
allow diffraction limited
observations in visible above
~600nm & 50mas resolution
below.
– Two mode-less lasers at
589nm & 569nm (giving 330nm
through radiative cascade)
– Polychromatic tip-tilt sensor
Use of a 330nm laser for tip-tilt
sensing (that would give both
wavelengths at once) is also
contemplated, though feasibility
is not proven yet.
CV
47
MK LGS TWG
Mauna Kea Laser Policy: Changes?
48
MK LGS TWG
Other Issues
PW
49
MK LGS TWG
Next Steps
PW
50