D-TECT: SolPol measurements

National Observatory of Athens, ReACT & University of Hertfordshire - SolPol Solar Polarimeter

PIs: Dr. Vassilis Amiridis ([e-mail]), Prof. William Martin ([e-mail])
co-PI: Vasiliki Daskalopoulou ([e-mail]), Alexandra Tsekeri ([e-mail])

Database distribution under CC-BY-SA (CC) rights
GitHub:  @NOA-ReACT/SolPol

Each data folder includes the following for the individual locations of operation:

- `Data_Antikythera`:
folder containing all the raw .txt data acquired by SolPol when installed in the PANhellenic Geophysical Observatory of Antikythera - PANGEA, Greece
measurement period: September 2018 to March 2022
location: lat = 35.86099, long = 23.30982,alt = 193

\txt: data acquired with default instrument aperture size (@5.5mm) labeled as pol_DDMMYYYY_HHMM(in UTC)_antik_duration.txt

\txt_iris: data acquired with different aperture sizes (@4.5mm, 5.5mm and 7mm) labeled as polirisXX_DDMMYYYY_HHMM(in UTC)_antik_duration

\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)

- `Data_Athens`:
folder containing all the raw .txt data acquired by SolPol when installed in the National Observatory of Athens (NOA), Athens, Greece
measurement period: 18/04/2020 to 14/05/2020
location: lat = 37.966295, long = 23.710624,alt = 60

\txt: data acquired with default instrument aperture size (@5.5mm) labeled as pol_DDMMYYYY_HHMM(in UTC)_ath_duration.txt

- `Data_Cyprus`:
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
(lat = 35.14063, long = 33.38135,alt = 181)

\txt: data acquired with default instrument aperture size (@5.5mm) labeled as pol_DDMMYYYY_HHMM(in UTC)_cyp1_duration.txt

- `Data_Mindelo`:
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
(lat = 16.87775, long = -24.994889,alt = 20)

\txt: data acquired with default instrument aperture size (@5.5mm) labeled as poliris55_DDMMYYYY_HHMM(in UTC)_mndl_duration.txt

\txt_dark: closed aperture dark measurements labeled as poldark_DDMMYYYY_HHMM(in UTC)_mndl_duration

## Text file Header

The raw data `header` is:

SOLAR POLARIMETER

1. `Polarimeter Position [deg]`:
Instrument rotational position at 0 and 45 degrees from reference

2. `Rotator Position [deg]`:
Polarizer position in sets of [0, 40, 130, 220, 310] in degrees

3. `PEM Setting [nm]`:
Photoelastic Modulator Head operating wavelength, default 550nm

4. `Retardation [waves]`:
PEM induced retardation

5. `Wavelength Filter (Wavelength-Bandwidth)`:
Filter wheel filter selection, default 550nm

6. `ND-Filter`:
Neutral density 0.3 filter (pre-defined)

7. `Time (UTC)`:
Measurement starting time in HH:MM:SS (UTC)

8. `Bias Voltage on Diode`
Should be zero if instrument working properly, forward bias

9. `LabJack, mean DC (AIN0)`:
DC output voltage from the DAQ in Volts

10. `LabJack, other`:
State zero if instrument works properly

11. `Lock-in, 1w`:
RMS Voltage output from channel 1 of the Lock-in amplifier, signal phase on resonant frequency (ω) in degrees

12. `Lock-in, 2w`:
RMS Voltage output from channel 2 of the Lock-in amplifier, signal phase on twice the resonant frequency (2ω) in degrees

## Data validity

! Data file to be valid needs to contain **5** sets of measurements [1-12 above] for each `Rotator Position [deg]` per `Polarimeter Position [deg]`.

! Every valid file stops at a `Polarimeter Position [deg]` == 45 degs & `Rotator Position [deg]` == 310.

雅典国家天文台（National Observatory of Athens）、ReACT团队与赫特福德郡大学（University of Hertfordshire）——SolPol太阳偏振仪数据集

主要研究者（PIs）：瓦西里利斯·阿米里迪斯博士（Dr. Vassilis Amiridis，邮箱：[e-mail]）、威廉·马丁教授（Prof. William Martin，邮箱：[e-mail]）；联合主要研究者（co-PI）：瓦西利基·达斯卡洛普卢（Vasiliki Daskalopoulou，邮箱：[e-mail]）、亚历山德拉·泽凯里（Alexandra Tsekeri，邮箱：[e-mail]）

本数据集采用知识共享署名-相同方式共享（CC-BY-SA）协议进行分发，GitHub仓库地址：@NOA-ReACT/SolPol

各数据文件夹对应不同观测部署地点，包含如下内容：

- `Data_Antikythera`：该文件夹存储SolPol安装在希腊安提基特拉泛希腊地球物理天文台（PANhellenic Geophysical Observatory of Antikythera - PANGEA）时采集的全部原始.txt格式数据，观测时段为2018年9月至2022年3月，观测地点坐标为纬度35.86099、经度23.30982，海拔193米。
- 常规.txt文件：使用仪器默认孔径（@5.5mm）采集的数据，命名格式为`pol_DDMMYYYY_HHMM(in UTC)_antik_duration.txt`，其中DDMMYYYY为观测日期，HHMM为协调世界时（UTC）下的观测时刻，duration为观测时长。
- txt_iris文件：使用不同孔径（@4.5mm、5.5mm和7mm）采集的数据，命名格式为`polirisXX_DDMMYYYY_HHMM(in UTC)_antik_duration`，XX为孔径标识。
- txt_dark文件：闭孔径暗场测量数据，命名格式为`poldark_DDMMYYYY_HHMM(in UTC)_antik_duration`，根据仪器跟踪器状态分为未跟踪（NT索引）与标准跟踪（T索引）两类。

- `Data_Athens`：该文件夹存储SolPol安装在希腊雅典国家天文台（National Observatory of Athens, NOA）时采集的全部原始.txt格式数据，观测时段为2020年4月18日至2020年5月14日，观测地点坐标为纬度37.966295、经度23.710624，海拔60米。常规.txt文件命名格式为`pol_DDMMYYYY_HHMM(in UTC)_ath_duration.txt`，采用仪器默认孔径@5.5mm采集。

- `Data_Cyprus`：该文件夹存储SolPol在塞浦路斯尼科西亚塞浦路斯研究所开展的2019年ASKOS预实验期间采集的全部原始.txt格式数据，观测地点坐标为纬度35.14063、经度33.38135，海拔181米。常规.txt文件命名格式为`pol_DDMMYYYY_HHMM(in UTC)_cyp1_duration.txt`，采用仪器默认孔径@5.5mm采集。

- `Data_Mindelo`：该文件夹存储SolPol在佛得角明德卢海洋科学中心（Ocean Science Centre Mindelo, OSCM）开展的2022年ASKOS实验期间采集的全部原始.txt格式数据，观测地点坐标为纬度16.87775、经度-24.994889，海拔20米。
- 常规.txt文件：采用仪器默认孔径@5.5mm采集的数据，命名格式为`poliris55_DDMMYYYY_HHMM(in UTC)_mndl_duration.txt`。
- txt_dark文件：闭孔径暗场测量数据，命名格式为`poldark_DDMMYYYY_HHMM(in UTC)_mndl_duration`。

## 文本文件头

原始数据文件头信息如下：

# 太阳偏振仪
1. **偏振仪位置（Polarimeter Position [deg]）**：仪器相对于参考基准的0°与45°旋转位置
2. **旋转台位置（Rotator Position [deg]）**：偏振器位置，取值集合为[0, 40, 130, 220, 310]（单位：度）
3. **光弹调制器设置（PEM Setting [nm]）**：光弹调制器（Photoelastic Modulator, PEM）工作头的操作波长，默认值为550nm
4. **延迟量（Retardation [waves]）**：光弹调制器引入的相位延迟量（单位：波数）
5. **波长滤光片（Wavelength Filter (Wavelength-Bandwidth)）**：滤光轮的滤光片选型，默认值为550nm
6. **中性密度滤光片（ND-Filter）**：预设0.3档中性密度滤光片
7. **时间（UTC）**：测量开始时刻，格式为HH:MM:SS（协调世界时）
8. **二极管偏置电压（Bias Voltage on Diode）**：若仪器工作正常，该值应为0，对应正向偏置状态
9. **LabJack设备直流平均输出（LabJack, mean DC (AIN0)）**：数据采集卡（DAQ）输出的直流电压，单位为伏特
10. **LabJack其他参数（LabJack, other）**：若仪器工作正常，该值应为0
11. **锁相放大器1ω通道（Lock-in, 1w）**：锁相放大器1号通道的均方根电压输出，对应谐振频率（ω）处的信号相位，单位为度
12. **锁相放大器2ω通道（Lock-in, 2w）**：锁相放大器2号通道的均方根电压输出，对应二倍谐振频率（2ω）处的信号相位，单位为度

## 数据有效性规则

1. 有效数据文件需针对每个**旋转台位置（Rotator Position [deg]）**，在每个**偏振仪位置（Polarimeter Position [deg]）**下包含上述1~12项的完整测量组数据。
2. 每份有效数据文件需以**偏振仪位置为45°且旋转台位置为310°**作为结束标记。