D-TECT: SolPol measurements

<p><strong>National Observatory of Athens, ReACT &amp; University of Hertfordshire - SolPol Solar Polarimeter </strong></p> <p>PIs: Dr. Vassilis Amiridis (vamoir@noa.gr), Prof. William Martin (w.e.martin@herts.ac.uk)<br> co-PI: Vasiliki Daskalopoulou (vdaskalop@noa.gr), Alexandra Tsekeri (atsekeri@noa.gr)</p> <p>Database distribution under CC-BY-SA (CC) rights<br> GitHub:&nbsp; @NOA-ReACT/SolPol</p> <p>Each data folder includes the following for the individual locations of operation:</p> <p>- `Data_Antikythera`:<br> folder containing all the raw .txt data acquired by SolPol when installed in the PANhellenic Geophysical Observatory of Antikythera - PANGEA, Greece<br> measurement period: September 2018 to March 2022<br> location: lat = 35.86099, long = 23.30982,alt = 193</p> <p>\txt: data acquired with default instrument aperture size (@5.5mm) labeled as pol_DDMMYYYY_HHMM(in UTC)_antik_duration.txt</p> <p>\txt_iris: data acquired with different aperture sizes (@4.5mm, 5.5mm and 7mm) labeled as polirisXX_DDMMYYYY_HHMM(in UTC)_antik_duration</p> <p>\txt_dark: closed aperture dark measurements labeled as poldark_DDMMYYYY_HHMM(in UTC)_antik_duration, either with instrument tracker not tracking (NT index) or standard tracking (T index)</p> <p><br> - `Data_Athens`:<br> folder containing all the raw .txt data acquired by SolPol when installed in the National Observatory of Athens (NOA), Athens, Greece<br> measurement period: 18/04/2020 to 14/05/2020<br> location: lat = 37.966295, long = 23.710624,alt = 60</p> <p>\txt: data acquired with default instrument aperture size (@5.5mm) labeled as pol_DDMMYYYY_HHMM(in UTC)_ath_duration.txt</p> <p><br> - `Data_Cyprus`:<br> folder containing all the raw .txt data acquired by SolPol for the duration of the preliminary ASKOS 2019 campaign, in the Cyprus Institute - Nicosia, Cyprus<br> (lat = 35.14063, long = 33.38135,alt = 181)</p> <p>\txt: data acquired with default instrument aperture size (@5.5mm) labeled as pol_DDMMYYYY_HHMM(in UTC)_cyp1_duration.txt</p> <p><br> - `Data_Mindelo`:<br> folder containing all the raw .txt data acquired by SolPol for the duration of the ASKOS 2022 campaign, in the Ocean Science Centre Mindelo (OSCM) - Mindelo, Cape Verde<br> (lat = 16.87775, long = -24.994889,alt = 20)</p> <p>\txt: data acquired with default instrument aperture size (@5.5mm) labeled as poliris55_DDMMYYYY_HHMM(in UTC)_mndl_duration.txt</p> <p>\txt_dark: closed aperture dark measurements labeled as poldark_DDMMYYYY_HHMM(in UTC)_mndl_duration</p> <p><br> ## Text file Header</p> <p>The raw data `header` is:</p> <p>SOLAR POLARIMETER</p> <p>1. `Polarimeter Position [deg]`:<br> Instrument rotational position at 0 and 45 degrees from reference</p> <p>2. `Rotator Position [deg]`:<br> Polarizer position in sets of [0, 40, 130, 220, 310] in degrees</p> <p>3. `PEM Setting [nm]`:<br> Photoelastic Modulator Head operating wavelength, default 550nm</p> <p>4. `Retardation [waves]`:<br> PEM induced retardation</p> <p>5. `Wavelength Filter (Wavelength-Bandwidth)`:<br> Filter wheel filter selection, default 550nm</p> <p>6. `ND-Filter`:<br> Neutral density 0.3 filter (pre-defined)</p> <p>7. `Time (UTC)`:<br> Measurement starting time in HH:MM:SS (UTC)</p> <p>8. `Bias Voltage on Diode`<br> Should be zero if instrument working properly, forward bias</p> <p>9. `LabJack, mean DC (AIN0)`:<br> DC output voltage from the DAQ in Volts</p> <p>10. `LabJack, other`:<br> State zero if instrument works properly</p> <p>11. `Lock-in, 1w`:<br> RMS Voltage output from channel 1 of the Lock-in amplifier, signal phase on resonant frequency (&omega;) in degrees</p> <p>12. `Lock-in, 2w`:<br> RMS Voltage output from channel 2 of the Lock-in amplifier, signal phase on twice the resonant frequency (2&omega;) in degrees</p> <p>## Data validity</p> <p>! Data file to be valid needs to contain **5** sets of measurements [1-12 above] for each `Rotator Position [deg]` per `Polarimeter Position [deg]`. &lt;br /&gt;</p> <p><br> ! Every valid file stops at a `Polarimeter Position [deg]` == 45 degs &amp; `Rotator Position [deg]` == 310.</p> <p>&nbsp;</p>