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Moon Surface Temperature @2.77cm Wavelength by Christian Monstein

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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  1. Moon Surface Temperature @2.77cm Wavelengthby Christian Monstein Bild: NASA Apollo-11

  2. 80cm offsetdish mounted on 5m-dish at Bleien observatory

  3. 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

  4. Collecting data and overview Moon rise Moon set

  5. Drift evaluation by 4th order- polynom

  6. Drift compensation ½(Tsky+Tsys+Tmoon) [dB] ½Tmoon [dB] -½(Tsky+Tsys) [dB]

  7. Histogramm creation dB

  8. 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)!

  9. 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

  10. 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:

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

  12. Final result

  13. 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

  14. Finito Christian Monstein HB9SCT Wiesenstrasse 13 CH-8807 Freienbach Private: cmonstein@swissonline.ch http://www.monstein.de/ Business: monstein@astro.phys.ethz.ch http://www.astro.phys.ethz.ch/rapp/

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