>
> |
%META:TOPICINFO{author="SimonDicker" date="1201026858" format="1.0" version="1.1"}%
TPAR 18 observing log
Quick cycle was carried out starting at 22:00 hours.
At 00:00 the 2nd stage temperature was still at 4:00K so started observing at Q band while the reciver stabilized.
Weather - clear, but warm with a ground mist ~ 20 ft high.
Q-band OOF maps:
Scans 1-5 peak & focus all on 0854+2006
T_sys at q-band = 70K
az pointing -.02' el +0.13', lfcy -1.0mm
Scan 6 - q-band focus daisy - lfcy=-20, 8 arc second offset in pointing at start of the file (based on quadrant detector) - radius=2', period=25s - Overall the scan looks OK.
Scan 7 aborted
Scan 8 - q-band focus daisy, lfcy=-20, 14 arc second jump in poinint at start of scan, lasts about 10 seconds - tried different phase at start, same scan parameters.
Scan 9-14 - more focus daisy radius=2', period=60s, 120s duration, lfcy=-20mm - 6 arcsecond jump lasted about 20 seconds. LFCY's of [-20,-13,-6,1,8,15]
Scan 15-19 peak-focus - lfcy +1mm
Scan 20 OOF map -20mm
Scan 21 OOF map +1mm (best focus)
Scan 22 OOF map +22mm
Scans 23-27 point and focus
Scan 28 - aborted peak focus
Scan 29-31 OOF map lfcy's -20mm,+1mm,+22mm in az/el not encoder.
**For some reason the GBT is not centering the maps on the source**.
1:36am sky clear above us - maybe some clouds over mountain - The maps just will not center.
Scan 32-36, peak & focus - lfcy=-0.33mm, az=-0.0143', el 0.0927'
Scans 37 aborted because of 10' jumps at the turnarounds. Was to be: Q-band OOF maps with wider el scan to get source neerer the center of the map.- big (25' jump in the quadrant detector at the start of the scan.
Brian updated the path to get round this.
Scans 38 q-band OOF - figured out what the problem is - the q band beams are offset from boresight.
CORRECT THIS use beam 1 NOT beam C
Scan 39-41 OOF maps using beam 1. -20,+1,+22mm (back to the narrower scan)
PUT MUSTANG IN THE FOCUS
biases set up using cal by hand - no down ramp taken so we can take an OOF map quicker
Scan 42 CAL scan (1.2V) - bad file
ASTRID crashed - restarted
Scan 43 CAL scan (1.2V) - 56 working detectors
Scans 44-47 parfocus daisy -20,-10,0,5mm daisy rad=0.7', period 25s excitation of feedarm V. small.
Scans 48-52 parfocus daisy -2,0,2,4,6mm 0.3' radius
Scans 53,54 focus daisy +8,+10mm - BEST focus = 2mm = peak amplitude, 4mm = most round - choose 2mm
Scan 55 quick daisy at 2mm, 100seconds, period = 25s, 0.3' radius.
Scans 56,57,58 OOF at -7mm,2mm,11mm
We are seeing 10" jumps in the feed-arm at the start of the OOF maps.
Scans 59,60,61 repeat OOF
Scan 62 30 second blank scan
Scan 63 CAL file
TURN zernikes off
Repeat OOF map
Scans 64,65,66 OOF with zernikes off
GO TO MARS :)
67 aborted
Scans 68-75 focus daisies on Mars -20,-15,-10,-5,0,5,10,15
Scan 76 subreflector scan -30mm to +30mm in 30 seconds
Scan 77 subreflector scan -30mm to +30mm in 120 seconds
Scans 78,79,80 focus scans -2mm, 0mm, +2mm
Scan 81 subreflector daisy
Scan 82 subreflector daisy with 2arcminute offset in az - 1/f noise has started to come - we are too low 26 degrees elevation.
Scan 83 30 seconds on blank field for weight at low elevation.
THE WIND IS ZERO - the fog is not.
Scan speed tests.
3C279 (1256+0547)
Scan 84 - aborted
Scan 85 - blank scan (30 seconds)
Scan 86 - CAL 1.2V - only on for half the file
Scan 87 - CAL file 1.2V
Scans 88,89,90,91,92 focus scans -15,-8,-1,6,13
We still see 1/f noise in most the detectors
Scan 93 - a tipping scan going up to access to see if noise goes away.- It does
Scan 94 Cal 1.2V
Scan 95 Blank
Scan 96 - tip back down to see if noise comes back.
Scan 97 quick daisy in focus (-1mm)
TESTS OF MAPPING
Scan 98 r=0.3', p=20s, 120s q-daisy -
Scan 99 r=0.3', p=10s, 120s q-daisy - quad detector +-2" (8 at start)
Scan 100 r=1.6' period=50s, 120s q-daisy
Scan 101 r=1.6' period=30s, 120s q-daisy - peak quadrant detector offset 4', settled down in 10s to 2'
Scan 102 r=1.6' period=20s, 120s q-daisy - peak offset 6', after 10 seconds settles down to 3'
At the moment it is reading degraded, noise & out of range.
Scan 103 r=1.6' period=10s, 120s q-daisy - peak offset 5', after 10 seconds settles down to few arcseconds.
Scan 104 r=1.6' period=10s, 120s q-daisy - :-) fast scans look fine - we can map quickly
Scan 105 r=11' period=30s, 120 seconds
Scan 106 r=11' period=20s, 120 seconds q-daisy - 10 arc second bump in quadrant detector, settles doown to around 5-6' - clearly part of scan pattern
Scan 107 r=11' period=10s, 120 second q-daisy - 18 arcsecond spike + 10 arcseconds oscillations in our scan stratagy
Scan 108 subreflector daisy centered on source.
Scan 109 subreflector daisy 2' offset for source in az.
;-( subreflector daisy gives BAD beams off-axis
Scan 110 Cal 1.2V
Scan 111 blank 30 seconds
Scans 112,113,114 quick focus lfcy -6,0,6mm
Go to 1120+237 (50-100mJy source)
Scans 115,116,117 Focus lfcy -6,0,6mm
Scan 118 r=0.3', p=20s, 120s q-daisy
Scan 119 r=0.3', p=10s, 120s q-daisy
Scan 120 r=1.6' period=50s, 120s q-daisy
Scan 121 r=1.6' period=30s, 120s q-daisy
Scan 122 r=1.6' period=20s, 120s q-daisy .
Scan 123 r=1.6' period=10s, 120s q-daisy
-- SimonDicker - 22 Jan 2008 |