GuentherWuchterl at 13:27, 28 April 2016

2016-04-28T13:27:32Z

GuentherWuchterl: Created page with "Since November 20, 2009 we measured at the [http://www.dwd.de/mol Meteorological Observatory Lindenberg (Richard-Aßmann-Observatory)] with the L52 Lightmeter (03.02 marks V05..."

2016-04-28T13:27:09Z

Created page with "Since November 20, 2009 we measured at the [http://www.dwd.de/mol Meteorological Observatory Lindenberg (Richard-Aßmann-Observatory)] with the L52 Lightmeter (03.02 marks V05..."

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Since November 20, 2009 we measured at the [http://www.dwd.de/mol Meteorological Observatory Lindenberg (Richard-Aßmann-Observatory)] with the L52 Lightmeter (03.02 marks V05.05 S / N 908052.1382). The Lightmeter is located on the northwest side of the radiaton platform near two modified [http://www.mobotix.com/eng_GB/Products/Cameras/Hemispheric-Q24 MOBOTIX - Hemispheric Q24 security cameras] for [http://www.dwd.de/bvbw/generator/DWDWWW/Content/Forschung/FELG/Bilder/cloud,property=default.jpg sky monitoring].

Coordinates: [http://maps.google.de/maps?f=q&source=s_q&hl=de&geocode=&q=52%C2%B012'32%22+N+14%C2%B007'17%22+E&mrt=kmlkmz&sll=52.209073,14.121648&sspn=0.004898,0.009624&ie=UTF8&hq=&hnear=Deutschland&ll=52.208895,14.12138&spn=0.019592,0.038495&t=k&z=15 52°12'32" N 14°07'17" E]

Height: 127 m asl (platform)

For the extension of the USB cable from the Lightmeter to the laptop (about 10m), we used the [http://www.lindy.de/usb-extender-premium-bis-50m-ueber-cat5-kabel/42801.html Lindy USB Extender PREMIUM].

[http://www.astroamateur.de/LIGHTMETER/L52.png Measurements (previous day)]

[http://dc.zah.uni-heidelberg.de/lightmeter/q/data/static/DE_LINDENBERG_1/ Directory listing for DE_LINDENBERG_1]

<gallery>
Bild:L52_Dach_Gesamt.jpg|radiation platform, view to south / Strahlungsmessplattform in Lindenberg - Blick nach Süden
Bild:L52_1.jpg|lightmeter L52 on the northwest side of the radiation platform in Lindenberg / Lightmeter L52 an der Nordwestseite der Strahlungsmessplattform in Lindenberg
Bild:L52_2.jpg|lightmeter L52 and the MOBOTIX-camera / Lightmeter L52 und MOBOTIX-Kamera
Bild:20091120-20091121.png | results of the first night in Lindenberg 2009-11-20/21 / Ergebnisse der ersten Messnacht in Lindenberg 2009-11-20/21
Bild:20110504_231235_lightmeter.png | registration of a bright fireball on May 4, 2011 23:12:35 UTC
</gallery>

=Calibration 21 Feb 2010=

X = c ( b (a exp (n/a) - 1) + n )

n ... counts (sensor output)
X ... physical quantity (total radiation in [W/m²] or horizontal illumination [Lux])

a = 9.776e+04, b= 1.991e-04, c= 2.662e-09 W/m²
a = 9.776e+04, b= 1.991e-04, c= 2.538e-07 Lux

Data from morning twilight and daylight, Feb. 17th 2010 2:07 - 11:00 UTC

--[[Benutzer:GuentherWuchterl|GuentherWuchterl]] 18:43, 21. Feb. 2010 (UTC)

=Improved calibration 24 Feb 2010=

Checks with a total radiation sensor showed up to 40% deviations near noon. In a new fit the
temperature dependence is included and the total radiation model is used for nominal site
parameters (dew-point temperature, surface pressure). Data are the same as above (Feb 17th
morning twilight to noon).

X = c ( b (a exp (n(1+dT)/a) - 1) + n )

n ... counts (sensor output)
X ... physical quantity (total radiation in [W/m²] or horizontal illumination [Lux])

a = 1.0118e+05, b = 4.9571e-04, c = 2.5688e-09, d = 2.3697e-03 [W/m²]
a = 1.0118e+05, b = 4.9571e-04, c = 2.3298e-07, d = 2.3697e-03 [Lux]

Background x0=6.3 mlx

Accuracy check with independent total radiation measurement shows the calibration
to be accurate to 12%. Note that the Sun used as calibrator never rises higher than
30° during the calibration period and thus accuracy of the total radiation model used for calibration is necessarily limited and the likely accuracy limiting element in the
calibration.

[[media:Lindenberg Kalibration.zip|.zip with graphs relating to the calibration and its check by independent total /global radiation measurments]]

There is indication for some cloud towards the begin of the morning twilight near the
background.

--[[Benutzer:GuentherWuchterl|GuentherWuchterl]] 01:25, 24. Feb. 2010 (UTC)

Check, Feb 27th, repetition of calibration procedure:

5:03 - 11:18 UTC

a = 1.0118e5, b = 4.9571e-4, c = 2.5754e-9, d = 2.3697e-3 [W/m²]
a = 1.0118e5, b = 4.9571e-4, c = 2.3298e-7, d = 2.3697e-3 [Lux]

X0 = -6.2552e-3 Lux

Conversion Lux-model to Total-radiation model

Lux = 90.465 Watt/m²
Watt/m² = 0.011054 Lux

copies from python-session

In [9]: SJD=(X.JD > mx.DateTime.DateTime(2010,2,17,5,03).jdn)
& (X.JD < mx.DateTime.DateTime(2010,2,17,11,18).jdn)
In [10]: X.fit_em1_to_natLight(JD_select=SJD,type='em1c0T')
Out[10]: (array([ 1.01179142e+05, 4.95712792e-04, 2.32981477e-07
, -6.25516123e-03, 2.36965039e-03]),

plot_date(X.JD-X.pylab_JD0
,X.Sunlight_Watt_per_square_meter_from_JD_DM(X.JD,surface_pressure=998.0,
T_dew_C=-9.0)
*0.778/X.Watt_per_square_meter_per_Lux
,'y,', label='DM model,P=998/T_d=-9/k=2.78')

--> In [44]: 0.778/X.Watt_per_square_meter_per_Lux Out[44]: 90.465116279069775
--> In [45]: 1./(0.778/X.Watt_per_square_meter_per_Lux) Out[45]: 0.011053984575835474

In [59]: plot_date(X.JD-X.pylab_JD0
,X.em1T(X.Strom,X.Temperatur
,1.01179142e+05, 4.95712792e-04, 2.57537e-09
,2.36965039e-03)
,'k,',label="a,b,c,d= 1.01e5, 4.96e-4, 2.58e-9, 2.37e-3"

=Notices=

For the measurement of global radiation on the observatory we use a CM22 pyranometer from Kipp & Zonen, which are used to measure the intensity of the radiation on flat surfaces.

= Weblinks =
* [http://www.kippzonen.com/?download/55152/CM+22+Pyranometer+-+Manual.aspx Kipp&Zonen CM22 Manual.] (engl.)

22:16, 5. Mai 2011 AndreKnoefel

WH --[[User:GuentherWuchterl|GW]] ([[User talk:GuentherWuchterl|talk]]) 15:27, 28 April 2016 (CEST)

@@ Line 16: / Line 16: @@
 <gallery>
-Bild:L52_Dach_Gesamt.jpg|radiation platform, view to south / Strahlungsmessplattform in Lindenberg - Blick nach Süden
+File:L52_Dach_Gesamt.jpg|radiation platform, view to south / Strahlungsmessplattform in Lindenberg - Blick nach Süden
-Bild:L52_1.jpg|lightmeter L52 on the northwest side of the radiation platform in Lindenberg / Lightmeter L52 an der Nordwestseite der Strahlungsmessplattform in Lindenberg
+File:L52_1.jpg|lightmeter L52 on the northwest side of the radiation platform in Lindenberg / Lightmeter L52 an der Nordwestseite der Strahlungsmessplattform in Lindenberg
-Bild:L52_2.jpg|lightmeter L52 and the MOBOTIX-camera / Lightmeter L52 und MOBOTIX-Kamera
+File:L52_2.jpg|lightmeter L52 and the MOBOTIX-camera / Lightmeter L52 und MOBOTIX-Kamera
-Bild:20091120-20091121.png | results of the first night in Lindenberg 2009-11-20/21 / Ergebnisse der ersten Messnacht in Lindenberg 2009-11-20/21
+File:20091120-20091121.png | results of the first night in Lindenberg 2009-11-20/21 / Ergebnisse der ersten Messnacht in Lindenberg 2009-11-20/21
-Bild:20110504_231235_lightmeter.png | registration of a bright fireball on May 4, 2011  23:12:35 UTC
+File:20110504_231235_lightmeter.png | registration of a bright fireball on May 4, 2011  23:12:35 UTC
 </gallery>

Lindenberg - Revision history

GuentherWuchterl at 13:27, 28 April 2016

GuentherWuchterl: Created page with "Since November 20, 2009 we measured at the [http://www.dwd.de/mol Meteorological Observatory Lindenberg (Richard-Aßmann-Observatory)] with the L52 Lightmeter (03.02 marks V05..."