Light Curve Analyzer
Load one comet's observations, select returns/types/observers, display reduced light curves and fit the standard brightness law over the visible data range.
Source-verified Data loading, formula syntax, plot controls, fitting, selections and persistent magnitude parameters were checked against the current implementation.
Basic workflow
- Select comet and enter its short designation.
- KOPR loads local valid observations and the saved regular formula(s) for that comet.
- Optionally use Load COBS data or Load MPC data to add observations.
- Use Settings and selections to choose returns, observation types and observers.
- Select axes and set the displayed range.
- Click Analyse to fit the observations currently visible and selected.
- Review the dashed additional formula, then copy/edit it into the regular formula area if it should become the adopted model.
Observation sources
Local data
The comet's local ICQ observation file is the plotting source. Open local data opens it in an editor; confirmed edits are written back.
COBS
Load COBS data imports available observations, merges them with the local file and removes duplicates through KOPR's observation-result processing.
MPC
Load MPC data obtains total/nuclear magnitude observations and opens the MPC filtering dialog before merging them. Some comets have no usable MPC magnitude data.
After an import KOPR reloads the plotting data and adds newly encountered observer codes to the observer selection.
Plot controls
| Control | Choices / behaviour |
|---|---|
| X axis | Date, Days from T, heliocentric distance r, or Log(r). |
| Y axis | Observed magnitude or reduced magnitude mag − 5 log(Δ). |
| Ranges | Four editable bounds. Refresh redraws using exactly those limits. |
| Compare | Displays personal/observer comparison information supported by the analysis settings. |
| Matplotlib toolbar | Zoom, pan and save the current graph. The numeric range fields, rather than toolbar zoom alone, define which observations Analyse uses. |
Date and Days-from-T use a single graph. The r and Log(r) choices use separate pre- and post-perihelion panels, with the pre-perihelion distance axis inverted.
Brightness formulas
Regular formula lines use the following syntax:
H0=9.46 mag, n=10.15 [-232.9, 0.0]
H0=8.71 mag, n=5.05 [0.0, 472.6]The model represented by KOPR is the standard reduced-magnitude relation:
m = H0 + 5 log10(Δ) + 2.5 n log10(r)The bracketed values are the valid range in days from perihelion. A formula without a bracket is treated as valid over the full range. Regular formulas are drawn as solid lines; formula lines in Additional formula are drawn dashed.
Only lines beginning with H0= are parsed. Invalid lines are ignored rather than interpreted approximately.
Analyse the visible observations
Analyse always fits reduced magnitude against log(r). It uses only observations that pass the active return, type, observer, uncertainty/negative and numeric axis-range selections.
With a free slope, linear regression returns H0, n, number of observations and residual scatter. With Fixed slope, KOPR keeps the chosen n and estimates H0 from the reduced values. With Perihelion asymmetry, pre- and post-perihelion subsets are fitted separately.
The result is placed in Additional formula and immediately drawn as a dashed curve. It is not automatically stored as the comet's regular model.
Settings and selections
| Tab | Controls |
|---|---|
| Settings | Perihelion asymmetry; personal coefficients; Marcus dust phase function and d_90; correct observed magnitudes vs enhance the model curve; fixed slope and n; Bortle survival limit for long-period comets. |
| Exclude | Exclude uncertain observations, negative observations and observations near a selected border interval. |
| Types | Enable/disable CCD, filtered CCD variants, visual, MPC total and MPC nuclear observations and choose markers. |
| Returns | Enable individual perihelion returns and assign their plot colours. |
| Observers | Include or exclude observer codes found in the loaded data. |
Phase correction can either correct observations or enhance the plotted model. The graph labels which mode and d_90 are active. The Bortle survival line is shown only when enabled and calculable for the selected long-period comet.
Save adopted magnitude parameters
Save parses every valid formula line in the Regular formula field and replaces that comet's records in:
config-files/MagParams.datAdditional analysis results are not saved unless you deliberately place the desired formula in the Regular formula field. Back up config-files/ before replacing a large set of adopted parameters.
Interpretation and limits
- A regression describes the selected data; it does not prove one physical activity law over unobserved distances.
- Visual, CCD and MPC magnitude systems can have systematic offsets. Use type/observer selections and personal coefficients deliberately.
- Phase correction is model-dependent and especially influential at large phase angles.
- Separate pre/post fits can be useful, but sparse coverage can make one branch unstable.
- Imported data should be inspected for duplicates, inconsistent magnitude definitions and outliers before saving an adopted formula.
Related chapters
Create visual observations · Create CCD observations · Use brightness parameters in planning · Compare multiple comets · Local observation and formula files