Observation Planner

Generate a text ephemeris and a night-visibility diagram for one or more comets from the active observing location.

Source-verified Comet selection, COBS quick plots, parameter meanings, ephemeris output and diagram generation were checked against the current implementation.

Data and active configuration

Opening the Planner triggers an update of the local COBS summary data when possible. Ephemerides themselves are calculated from KOPR's local comet elements for the active location: longitude, latitude, elevation and GMT offset.

The planner does not ask for a separate site. Change the active location in KOPR before generating results.

Planner controls

Control	Default	Meaning
Start date	Current date	First date of the ephemeris/diagram.
Interval (days)	7	Number of days between generated ephemeris dates.
Steps	4	Number of generated steps.
Limit mag.	15	Faintest predicted magnitude accepted in the result.
Limit alt.	10°	Minimum comet altitude used for filtering.
Twilight reference	Astronomical	Use the end of astronomical (−18°), nautical (−12°) or civil (−6°) twilight.
Apply Marcus Phase Correction	Off	Apply the dust phase correction in magnitude prediction/plotting.
d_90	10	Parameter used by the phase-function calculation.

Select comets

Click Select Comets and enter short designations separated by commas, for example:

12P, C/2023 A3, 29P

An empty selection means all locally available comets that pass the magnitude and altitude limits. Explicit selection is preferable for a focused observing plan and avoids a very long output.

Generate an ephemeris

Select the comet list.
Set date, interval, steps, limiting magnitude and limiting altitude.
Select the twilight reference and optional phase correction.
Click Generate ephemeris.
Review the text in the right-hand output panel.

KOPR refuses the operation when start date, interval or step count is blank. The exact columns in the text output are produced by the current ephemeris generator; the output is intended to be read or saved as plain text rather than edited in place.

Interpret magnitude as a planning estimate. It depends on the comet's stored brightness parameters and the optional phase correction; it is not a guarantee of visual detectability under a particular sky background, instrument or observer.

Plot a night visibility diagram

Plot diagram calculates one night from the selected start date and active location. The background represents the night/twilight geometry and horizontal time ticks; each accepted comet is drawn as a labelled curve.

The plot uses a practical minimum altitude of 5 degrees internally, while the entered magnitude limit and optional phase correction remain active. The resulting Matplotlib window can be saved; its default format is EPS and the suggested filename is derived from the start-date field.

Curves near the top/bottom or crossing twilight boundaries should be interpreted together with the textual ephemeris and the actual local horizon.

Actual COBS data and quick analysis

The dropdown contains comets present in the current local COBS summary. Selecting one opens a simple plot of observed magnitudes against days from now and an internally calculated quick trend. This feature is a rapid context view, not the full Light Curve Analyzer.

If the list is empty or outdated, check internet access and local COBS data files. The planner can still calculate orbital ephemerides from local elements even when the COBS quick plot is unavailable.

Save ephemeris output

Save ephemeris writes the current text panel exactly as displayed to a user-selected file. Generate or refresh the ephemeris before saving; the diagram is saved separately from its Matplotlib window.

Common problems

Symptom	Action
Fill all required fields	Enter start date, interval and steps.
Expected comet is absent	Check spelling/elements, magnitude limit, altitude limit, observing location and date.
No COBS quick curve	Refresh online data or use Analyzer after loading observations; orbital planning remains independent.
Diagram does not reflect local horizon	The plot uses geometric altitude, not trees/buildings/mountains; apply local knowledge.
Unrealistic brightness prediction	Review stored comet magnitude parameters and whether phase correction is appropriate.

Related chapters

Active observing location · Light Curve Analyzer · Compare comets · Comet elements and observation data