Process Visual Obs.

Reduce a visual comet observation with an automatically generated comparison-star map, Argelander steps, optional extinction correction and standard ICQ output.

Source-verified Controls, map generation, coma and tail input, reference-star editing, validation and output were checked against the current implementation.

Requirements

The comet exists in the local orbital-element database.
The active location, telescope and eyepiece describe the visual observation.
Date and time are entered in UT as YYYY/MM/DD and HH:MM.
At least two usable reference stars are entered before processing.
The coma diameter is supplied; a tail position angle is required whenever a tail length is stated.

The map and all altitudes use the active KOPR location. The field size is derived from the active telescope/eyepiece configuration; the special Naked Eye telescope uses a 10-degree field.

Start a new observation

Click New observation. The prompt shows the active location, telescope and eyepiece.
Enter the short comet designation, for example 103P or C/2012 X1.
Enter UT date and time. Clicking either field after both are valid initializes or refreshes the map.
Review geometry. KOPR displays geocentric distance, heliocentric distance, comet altitude, Sun altitude and Moon altitude.

If orbital elements are missing, KOPR opens the add-comet workflow instead of constructing the map.

Generated comparison-star map

The initial map is centred on the calculated J2000 comet position. KOPR estimates a limiting magnitude two magnitudes fainter than the predicted comet, rounded to half a magnitude and constrained to the range 6–18.

Initial limit	Initial catalogue
6–7 mag	YBSC5
Above 7 to 12 mag	TYC-2
Above 12 mag	UCAC4

Map parameters lets you change centre RA/Dec in degrees, map size, limiting magnitude and catalogue. Rebuilding the map clears all selected reference stars and previous coma/tail overlays, so make map changes before entering the final observation.

The white plotted circles are scaled by catalogue magnitude. The red comet marker is the calculated position, not an independent confirmation of the observed condensation.

Measure on the map

All map selections use the right mouse button.

Measure Coma

Right-click two opposite edges of the visible coma. KOPR derives the angular diameter in arcminutes and draws a circle centred on the calculated comet position. The follow-up dialog can switch to stars, tail or repeat the coma.

Measure Tail

Right-click the visible tail endpoint. The starting point is the calculated comet position. KOPR fills tail length in degrees and position angle in degrees.

Measure Stars

Right-click near a plotted catalogue star, then enter its Argelander degree. KOPR stores the catalogue magnitude, star altitude and catalogue identity. Hold Shift while right-clicking a selected star to remove it.

Map interaction is geometric assistance, not image measurement. The user remains responsible for identifying the real coma edge, tail endpoint and comparison stars used during the visual observation.

Observation fields

Field	Meaning
Estimate method	Morris, Sidgwick or Bobrovnikoff; the corresponding ICQ method code is taken from the first letter.
Coma diameter	Total apparent coma diameter in arcminutes.
Degree of condensation	No DC or an ICQ-style value from 0 to 9, including slash variants.
Tail length / Position angle	Tail length in degrees and position angle in degrees. Both may be left empty when no tail is reported.
Observation type	Positive, Uncertain or Negative. These choices set the corresponding ICQ uncertainty/negative flags.
Extinction	No Extinction, Winter, Spring/Autumn or Summer. When enabled, KOPR corrects comet and each star separately from their altitudes and observer elevation.
Comment	Optional observer note appended to the generated metadata comment.

Reference stars

Reference stars opens a table containing every selected star. You can include/exclude individual stars and edit Argelander degree, catalogue magnitude, B−V value and altitude. The selected magnitude-source code is shared by the solution.

For no extinction correction, Argelander degree and star magnitude are required. When extinction is enabled, star altitude is required as well. Clear all stars removes the solution; Cancel retains the previous values.

KOPR fits catalogue magnitude versus Argelander degree using the included stars. A valid estimate therefore needs comparison stars on both sides of the comet brightness scale, not only stars that are all brighter or all fainter.

Process the observation

Process obs. validates reference stars, coma and tail fields, calculates the comet/Sun/Moon geometry, applies the selected extinction model and fits a straight Argelander relation. The fitted intercept is the resulting comet magnitude.

Processing is blocked when the comet is below the horizon, the stated observation is physically incompatible with daylight/twilight, extinction is missing below 10 degrees altitude, the fitted slope is negative, or all comparison-star degrees lie on the same side of zero. Twilight, Moonlight and other quality conditions can produce warnings rather than a hard failure.

Result and saved output

The standard result dialog shows the fixed-width ICQ record, a second human-readable observation representation and an Argelander plot with measured stars and the fitted line. The generated comment includes comet altitude, Argelander steps, star magnitudes and source identifiers.

Use the result dialog's append action to write the ICQ record to the observer-code text file. Closing the dialog without appending does not save the observation.

Common problems

Symptom	Action
Elements not found	Update or add the comet's orbital elements before starting the observation.
Blank or incorrect map	Verify date/time, active location, field of view and catalogue; then rebuild with Map parameters.
No star found	Click closer to a plotted object or choose a catalogue/limit that contains the observed star.
Reference stars error	Enter at least two included stars, with valid Argelander degrees and magnitudes.
Negative slope	Check the signs/order of Argelander degrees; fainter catalogue stars must not become brighter in the fitted sequence.
Estimate error	Use at least one brighter and one fainter comparison star around the comet estimate.

Related chapters

Location, telescope and eyepiece configuration · Analyse saved observations · ICQ and local data formats · Troubleshooting