Optics
june 2002
Optics includes the surveys and adjustments to
the reflectors as well as the pitch, roll, and focus measurements.
TOPICS:
Historical events for the optics.
MISC:
Surveying the
primary
reflector
Surveying
the
dome position from AO9
Tilt
sensor measurements.
Surveying
the tertiary
Surveying the
horn positions.
Pitch, roll, and focus
using
theodolite and tilt sensors to compute the tiedown correction.
Field of view measurements.
Platform
height, position, temp, tiedown Position, and tensions.
Cable measurements
Standing waves
Computations
MISC
See
also: platform motions.
Historical events for the optics:
- 25apr06: sbn focus curve on J0745+101.
- 03,04aug05: Installed some beams in feed tower to brace
some beams
that were deflecting (probably from the kevlar cables).
- nov04 to jan05: PrimaryAdj2: adjust the 38000
panels of the
primary using the PrimaryMeas2 data (actually not all of the
panels
were readjusted0.
- 12oct04-30oct04 : measure/adjust the tertiary
- 07jun04-29jun04; measure/adjust the secondary.
- 14may04: sbw horn moved down to put it at correct phase
center.
- 02,08may04: horns surveyed into position. Some had been
moved to
make way for alfa. Also to correct for tertiary motion on 01may04.
- 01may04: tertiary survey (after alfa installed).
Updated
position
- 21apr04: alfa installed after reinforcing floor.
- ??apr04: kevlar cables in installed in feed tower
(before
alfa installed).
- 13feb04: sbh horn down .8 inches to
put it
at
correct phase center.
- 09jul03: ao9 survey of dome.
- mar03: PrimaryMeas2. finished measuring the photos from
primary
measure2
- 28feb03: sbn focus curve after dome moved.
- 27feb03: dome lifted by 1.65 inches
- 25feb03: shimming of elevation rails completed.
- 22nov02: lbw horn moved down 3.67" to put phase center
at
correct
spot.
- 28aug02: cb horn moved down 1.08 " to put phase center
in
correct
position.
- nov01-dec01: PrimaryMeas2. take another round of photos
of
38000
reflectors on primary. machine measuring did not finish until mar03.
- oct01-nov01: PrimaryAdj1. Adjust all 38000 panels on
primary.
- mar01-oct01: PrimaryMeas1. measure photos of all
38000 reflectors
on primary
- mar01: Adjust tiedown cables under primary (2nd
round
using
measurements from jan01)
- dec00: Adjust tiedown cables under primary
Surveying
the primary reflector (top)
I've tried to put together a timeline with names so
that i can reference different data sets below. The dates are only
approximate.
A lot of the adjusting overlapped with the previous measuring.
Measuring only the tiedown cables (2000 targets)
- M_TD0 dec00
measure
targets at reflector tiedown cables before any adjustments.
- ADJ_TD0 dec00 adjust dish at the measured
tiedown cables
using m_td0 data.
- M_TD1 jan01
remeasure
reflector targets at tiedown cables.
- ADJ_TD1 mar01: completed second adjustment
of
reflector
targets at tiedown cables using m_td1 data.
- M_TD2 mar01: as part of
m_sur1 below
just the tiedown cable targets were measured to compare with the m_td1
data.
Measuring/adjusting all 38000 targets.
- M_SUR1 mar01-oct01:
All 38000
targets now installed. Take photos and then measure on measuring
machine.
The photo measurements finished around oct01.
- ADJ_SUR1 oct01-nov01. After M_sur1 start adjusting all
the
panels.
This measurement finished around nov01.
- M_SUR2 nov01-mar03. After
ADJ_SUR1
take the photos in nov/dec01. Remeasure all the photos. The
measurements
and computations finished around mar03.
Primary
reflector surface errors measured jan01 after first re-alignment (M_TD1)
Primary
reflector surface errors measured mar01 after 2nd re-alignment (M_TD2)
Primary
reflector surface errors (east half). Photos taken oct,nov 2001
(M_SUR2).
Scatter
plot of radial errors survey1 vs survey2 (pdf file) (M_SUR1,M_SUR2).
Survey2
results (and a comparison with survey 1)
Surveying
the dome position from AO9 (top)
09aug01:
Theodolite survey from AO9 of dome position versus az,za (With AO9 as
origin)
09aug01:
Theodolite survey from AO9 of dome position versus az,za (With
reflector
as origin)
feb03
: theodolite survey from ao9 of dome position before and after shimming.
jul03:
theodolite survey from ao9.
Surveying
the horn positions. (top)
Horn
position surveys.
The
latest model offsets in az and za.
Finding
the best turret position by tracking sources.
Pitch, roll,
and focus using theodolite and tilt sensors to compute the tiedown
correction.
(top)
aug01
: The pitch/roll of the telescope versus az,za (using the theodolite
and
tilt sensors).
aug01
: The pitch/roll of the telescope versus az,za (using the theodolite
and
tilt sensors..Reflector origin).
aug01:
tiedown positions to correct for pitch, roll, and focus (reflector at
origin).
jan02:
Correlate pitch, roll with coma (cband).
feb02:
simulate tiedown motion after shimming (reflector at origin).
feb02:
shimming the elevation rails (reflector at origin).
Field of view
measurements.
(top)
10jun02:
Losses caused by offsetting the horn 19 and 25 cm using lbn and the
turret.
Platform
height, position, tiedown Position, and tension. (top)
year
2002:Tiedown tensions vs:platform height,temperature, and tiedown
Position.
Data and fits
year
2002:Td inches/platform inch, TdPos vs temp at platform focus position.
dec03:
platform corner height vs za when looking at tower.
jan10:
dynamic load on tiedowns from platform motion.
22feb10:
fit tiedown tensions using 2008,2009 data.
17mar10:
dome za that balances az arm when ch at stow.
18oct10: tdKips per platform motion
if 1 inch
Cable measurements: (top)
mar06:
td cable tensions and az,za positions when main cable catenary sag
meaurments
made.
Standing waves: (top)
jan05:
standing waves measured by moving the platform with the tiedowns.
Computations (top)
Aoant
simulation
of 10ghz focus position with 869.781 foot radius
Phase
delay along line feed needed for focusing.
MISC. (top)
Horizontal
offset of platform relative to AO9 monument.
Correlation
of the coma parameter and the pitch,roll, focus error (sband
narrow).
kildal
horn paper (includes phase center computation)
Tsys
versus
turret position for various receivers.
home_~phil