Moon surface temperature @2 77cm wavelength by christian monstein
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Moon Surface Temperature @2.77cm Wavelength by Christian Monstein. Bild: NASA Apollo-11. 80cm offsetdish mounted on 5m-dish at Bleien observatory. Receiving equipment. Software tools on ‚pisces‘: Windows 98 AR5000-control FLUKE45-control &capture VNC remote software

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Moon Surface Temperature @2.77cm Wavelength by Christian Monstein

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Moon surface temperature @2 77cm wavelength by christian monstein

Moon Surface Temperature @2.77cm Wavelengthby Christian Monstein

Bild: NASA Apollo-11


80cm offsetdish mounted on 5m dish at bleien observatory

80cm offsetdish mounted on 5m-dish at Bleien observatory


Receiving equipment

Receiving equipment

  • Software tools on ‚pisces‘:

  • Windows 98

  • AR5000-control

  • FLUKE45-control &capture

  • VNC remote software

  • Fictional Daemon ftp-server

  • Humidity-sensor

  • Temperature sensor

  • Apache www-server

Moon

Offset dish 80cm

beam switching-

mode 6° x 90sec

10,7...12,75GHz

AR5000

RS-232C

Power supply

+15V

via bias-T

Pentium 66MHz

IF1=950...2150MHz

75

Logarithmic

detector

AD8307

IF2=10,7 MHz

BW=220KHz

50

25mV/dB

RS-232C

FLUKE45

Ethernet


Collecting data and overview

Collecting data and overview

Moon rise

Moon set


Drift evaluation by 4th order polynom

Drift evaluation by 4th order- polynom


Drift compensation

Drift compensation

½(Tsky+Tsys+Tmoon) [dB]

½Tmoon [dB]

-½(Tsky+Tsys) [dB]


Histogramm creation

Histogramm creation

dB


Exception handling

Exception handling

  • Geostationary satellites between Moon and Earth

  • Sun within tracking path during new moon phase

  • Terrestrial man made noise

  • High noise temperature below 15° elevation

  • Rainfall increases atmospheric attenuation drastically

  • System failures (timing, pointing and other „Bill Gates-effects“)

  • Imperfect operator...

  • Radio-refraction not yet corrected (only optical)!


Analysis disc temperature

Analysis disc temperature

  • Antenna temperature: Ta = Tref*[10^(dB/10)-1], where Tref~94K

  • Compensation LNC-dustcover loss: c=0.1dB

  • Compensation atmospheric loss: a0=0.2dB...0.24dB...1.5dB (rain)

  • Compensation elevation effect: a=a0^[sin(*/180)^-1]

  • Evaluation proper antenna temperature. Tp=Ta* c* a

  • Evaluation antenna directivity with a sun transit measurement -> D

  • Evaluation antenna beam solid angle: a=(4* )/D ²

  • Evaluation moon disc area (~solid angle): m= *(/2)²

  • Evaluation moon brightness temperature: Tm=Tp* a/ m

  • Filtering with smoothed mean method by 9 hours observation time

  • Data approximation by a 6th order polynom


Estimation of tref

Estimation of Tref

1. Theoretical, due to noise figure (preamp) + ohmic losses(cover):

2. Solar radio noise (LEAR) as a reference:

3. Cold sky/horizon:

Average:


Estimation of antenna directivity by a transit meridian scan of the sun

Estimation of antenna directivity by a transit meridian scan of the sun


Final result

Final result


Observation parameter

Observation parameter

  • Observationtime: 7.1.2001-8.3.2001; 276 hours; 248657 samples

  • Sample rate: 5digit/4sec

  • Observationmode: beam-switching (6° resp. 8°) x 90´´

  • 1  (antenna temperature raw data): 0.5 Kelvin

  • 1  (moon disk temperature raw data): 22 Kelvin

  • 1  (moon disk temperature integrated data): 22 K/9 < 10 K (4%)

  • Mean disk temperature: 213 Kelvin

  • SNR signal to noise ratio: typically 8.6 dB

  • Estimation of temperature lag: t ~ 5 days

  • Observing frequency: 10.83 GHz = 2.77 cm wavelength

  • Observing bandwidth: 220 KHz

  • Integration time: pre=0.2sec, post=9h


Finito

Finito

Christian Monstein HB9SCT

Wiesenstrasse 13

CH-8807 Freienbach

Private:

[email protected]

http://www.monstein.de/

Business:

[email protected]

http://www.astro.phys.ethz.ch/rapp/


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