3mm testing in july 2001
DESCRIPTION
3mm Testing in July 2001. Tony Wong ATNF Epping CA Forum, 6 Sep. Bandpass at 90.56 GHz. 3c279 128 MHz 64 chans. Bandpass at 90.68 GHz. 3c279 128 MHz 64 chans. Bandpass at 90.68 GHz. After bandpass calibration applied. Phase/amp stability at 90 GHz. RMS 10 - PowerPoint PPT PresentationTRANSCRIPT
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3mm Testing in July 2001
Tony Wong
ATNF Epping
CA Forum, 6 Sep
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Bandpass at 90.56 GHz
3c279128 MHz64 chans
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3c279128 MHz64 chans
Bandpass at 90.68 GHz
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After bandpass
calibration applied
Bandpass at 90.68 GHz
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Phase/amp stability at 90 GHz
RMS 10but
amplitude variations
much greater!
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Phase/amp stability at 90 GHz
Phase cycles
every 20 minutes
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Phase/amp stability at 22 GHz
Amps decreasing- worsening weather?
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How often to calibrate?
5 min on 3c279:
10% amp fluctuation, RMS 15
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System Temperatures
Tsys, corrected for atmospheric absorption, was determined using
the paddle while stepping in frequency from 84-87
GHz.Some of the frequency variation may be due to
varying atmosphere.
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System Temperatures
Same observation for 87-91 GHz.
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System Temperatures
Since the “psJy” scale is derived
assuming constant GTsys of 500 Jy, the
visibility amplitude in psJy is anticorrelated
with Tsys.
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Sensitivity Estimate, 86 GHz
Assuming a flux of 8 Jy for Uranus, the observed amplitude and Tsys give the geometric mean Jy/K for the two antennas.
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Sensitivity Estimate, 90 GHz
Note strong RFI at 88.160 GHz. Significant RFI is also found at 88.000 and 88.320 GHz, weaker at 88.240 GHz.
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Some Science ResultsMolecules in IRC+10216
HCN
HNC
C3N
SiS
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Some Science ResultsDense Gas in the LMC
HCN
HCO+
Thermal SiO in N6334
W 17.5”
center