Planning guide

Planning, Visibility and Analyser

Visibility quickly discovers which objects can be photographed during a week from central Catalonia. Planning is for the technical study of one target, with a custom location, night-by-night comparison and five-minute samples.

When opened with the “Plan” button in Visibility, the object, week, year, day shift and altitude threshold load automatically.

When opened from the Analyser, the object, FOV width and height, and sensor orientation load automatically; “Use the latest FOV calculated in the Analyser” is selected. You only need to choose the location and period before calculating the nights.

1 · Location

L’Ampolla is the initial location. The selector also includes Barcelona, Pujalt, Huesca, Lleida, Tarragona, Girona and Vilanova i la Geltrú; you can enter any other latitude and longitude and an optional name.

The location lasts only for the current browser session. Any change marks the calculation as pending and requires observer-dependent data to be recalculated.

2 · Object

Only one input mode can be active: local list, SIMBAD, or manual J2000 RA/Dec. Under “Local list”, type a name, catalogue designation or alias and select a match from the gallery or pending targets.

“View photograph” appears only when the selected object belongs to the gallery and has an image. It opens the photograph in a viewer over Planning without leaving the page or losing the selection; close it with ×, by selecting outside it or with Esc. It is not shown for pending targets, SIMBAD or manual coordinates.

SIMBAD returns only a name and coordinates for the session and adds nothing to the gallery. If the object is already in the local catalogue, no external lookup is required.

3 · Time period and threshold

The block follows the same order as Visibility: year, ISO week, month, days and threshold. Month and days are read-only fields; the ‹ and › controls change the year or week, and the selected weekly period is shown in UTC before calculation.

“Day shift” moves the complete period up to three days earlier or later. “Altitude threshold” defines the minimum useful altitude from 30° to 60°. The calculation, comparison, chart and reports use those seven shifted dates and the selected threshold.

After changing the location, object, week, year, day shift or threshold, “Calculate nights” pulses. Calculation runs only when pressed.

Reading of the week

After calculation, the automatic reading identifies the most favourable night and shows its rating, useful window, Moonless time and the target’s culmination.

The comment interprets the geometry of all seven nights together and explains why that opportunity stands out. It is astronomical guidance: cloud, transparency, seeing, wind and local-horizon obstructions are not included.

4 · Seven-night comparison

Each row summarises astronomical night, maximum night altitude, the effective window above the selected threshold, Moon-down effective time, and the best times with the Moon below or above the horizon.

Illumination and separation refer to the best Moon-up time. A dash means the value does not apply. An outline identifies the night shown in the chart.

Interpreting the Moon

“Moon down” means the Moon is below the horizon within the effective window defined by the selected threshold. When visible, consider illumination, lunar altitude and angular separation together.

Greater separation is usually favourable, but filters, transparency and the target’s surface brightness also matter.

5 · Night detail

The 24-hour chart shows the object curve in green and the Moon curve in red, from −90° to +90°, with references at 0°, ±30°, ±60° and +90°. Shading marks astronomical night. The standard +30° reference is yellow; when another threshold is selected, its dashed line and legend also appear in blue. Segments outside darkness are dimmed.

On load, the cursor and data panel automatically mark the object’s highest point during astronomical night. Move the pointer to inspect another sample; on touchscreens, tap to inspect and drag to scroll across the chart. UTC time, object altitude and azimuth, lunar altitude and illumination, Moon–object separation and Sun altitude are shown at five-minute intervals.

6 · Check the framing

Reuse the latest FOV calculated in the Analyser, or enable “Override the FOV size” and enter a known field in the same inputs. A FOV transferred directly from the Analyser takes priority and also preserves the sensor orientation.

The object resolved in section 2 is shown to scale from its apparent size. Rotate the sensor in ±15° steps; if the catalogue or SIMBAD provides no size, enable manual apparent-size entry.

The result states whether the object fits with room, is tight or does not fit completely, and the framing is included in the PDF.

Download results

The TXT-icon “Download TXT” button creates a text summary with the target, location, period, automatic reading and seven-night comparison.

The PDF-icon “Download PDF” button creates a two-page report: the first page summarises the week, while the second contains the chart and data for the selected night. Everything is generated in the browser and no personal data is stored.

Model and limits

Positions are geometric and topocentric, without atmospheric refraction. Moon–object separation is topocentric as well.

Weather, clouds, humidity, terrain, obstructions, local light pollution, transparency and seeing are not modelled. Always check real conditions before a session.