This repository contains digitized records and reconstructed sunspot positions from observations by French astronomer H. Flaugergues in the period 1788–1830.
Destription of the method is presented in the paper Sunspot positions from observations by Flaugergues in the Dalton Minimum
- records - files with digitized records, separated by observation schemes
- utils - source functions for calculation of heliographic coordinates
- coordinates.csv - reconstructed coordinates for each record
- sunspots.csv - sunspot positions averaged over multiple records for the day
coordinates.csv
| Column name | Description |
|---|---|
| obs_id | Unique id of the record (note the the record can contain several spots) |
| recorded_time | Original start time of the record |
| sidereal | True, if recorded time is sidereal |
| utc_time | Estimated UTC time corresponding to the recorded_time |
| name | Sunspot name |
| lat | Latitude (degrees) |
| long | Carrington longitude (degrees) |
| cmd | Central meridian distance (degrees) |
| outlier | True, if we assume the record is invalid |
| type | Type of measurements: "hv" for horizontal and vertical wires, "ob" for oblique wires, "rh" for rhomboid scheme, "ec" for eclipse |
| x | x-coordinate in the coordinate system aligned with solar motion (see the paper for definition) |
| y | y-coordinate in the coordinate system aligned with solar motion (see the paper for definition) |
| rising | True, if we assume that the record is before noon |
| l0 | Solar L0 angle (degrees) for the time of observation |
| b0 | Solar B0 angle (degrees) for the time of observation |
| p | Solar P angle (degrees) for the time of observation |
| incl | Angle (degrees) between the line of solar motion and the parallel line of the telescope for the time and place of observation |
| incl_obs | Angle (degrees) between the line of solar motion and the parallel line of the telescope derived from the record (if applicable) |
| incl_diff | Calculated absolute difference (in degrees) between inclination of the line of solar motion at the beginning of the observation and at the end of the observation |
| err | Positioning error (degrees, if applicable) |
| r_sun | Solar "radius" measured in time units (seconds) |
| modified | True, if original record was modified to correct possible miswritings |
| complemented | True, if we complemented the original record with additional information that allows reconstruction of coordinates |
sunspots.csv
| Column name | Description |
|---|---|
| date | Date yyyy-mm-dd of observation |
| name | Sunspot name |
| lat_mean | Mean latitude |
| lat_std | Standard deviation for the latitude |
| long_mean | Mean Carrington longitude |
| long_std | Standard deviation for the longitude |
| cmd_mean | Mean central meridian distance |
| cmd_std | Standard deviation for the central meridian distance |
| n | Number of records used in averaging |
| reliable | True, if there are sunspots with similar coordinates before or after this day |
For description of the digitized data see the folder records.
Egor Illarionov, Rainer Arlt, Sunspot positions from observations by Flaugergues in the Dalton Minimum, Monthly Notices of the Royal Astronomical Society, 2023; https://doi.org/10.1093/mnras/stad1489