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:
- 28oct12: new sbn
receiver installed. The tilt sensor box was removed and then a
new smaller box was installed. Need to check the alignment.
- 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.
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