Polar Mount Satellite Angle Calculator

Calculator Inputs

Example Data Table

Formula Used

Use signed degrees. East longitudes are positive. West longitudes are negative.

Longitude difference: d = satellite longitude - site longitude.

Let φ be latitude, and k be earth radius divided by orbit radius.

x = cos(φ) × cos(d).

Elevation = atan2(x - k, √(1 - x²)).

True azimuth = atan2(sin(d), -sin(φ) × cos(d)). Normalize it to 0 through 360 degrees.

Polar declination offset = atan2(sin(|φ|), (1 / k) - cos(|φ|)).

Motor hour angle is found by converting elevation and azimuth to topocentric equatorial coordinates.

How to Use This Calculator

Enter your latitude and longitude in signed decimal degrees. Enter the target satellite longitude the same way.

Add the dish offset angle when using an offset reflector. Leave zero for a prime focus dish.

Enter magnetic variation only when you will use a magnetic compass. Keep east variation positive.

Press the calculate button. Read the result above the form. Set the mount axis first. Then set declination. Finally peak the signal.

Use the CSV or PDF button after entering the same values. The exported file keeps the calculated report.

Polar Mount Satellite Angle Guide

Why Polar Mount Angles Matter

A polar mount follows the Clarke belt by rotating around one tilted axis. This makes wide satellite scanning easier than using repeated azimuth and elevation changes. The axis must be aligned with the earth axis. The dish then needs a small declination drop. This calculator joins those steps with normal satellite pointing math.

Inputs and Results

It uses your site latitude, site longitude, and satellite longitude. It also accepts dish offset angle, magnetic variation, and earth orbit ratio. These options help field installers compare mount settings with real pointing angles. The result shows true azimuth, compass azimuth, elevation, polar axis elevation, declination offset, and motor hour angle.

Latitude and Declination

The latitude value controls the polar axis setting. In the north, the axis points near Polaris. In the south, it points toward the south celestial pole. The declination angle bends the dish downward from that polar axis. This lets the reflector follow the geostationary arc instead of a flat circle.

Longitude and Motor Movement

Longitude difference controls how far the motor must turn. A satellite near your local meridian needs little motor movement. A satellite far east or west needs a larger hour angle. The calculator also reports whether the satellite is visible above the horizon. Low elevation paths can suffer from trees, walls, rain fade, and alignment error.

Offset Dishes

Offset dishes need extra care. Their face does not point exactly where the signal travels. The offset angle is subtracted from the calculated elevation. That value gives a practical face reading for many bracket scales. Always confirm it with signal quality, not signal strength alone.

Reports and Records

The download buttons save results for work orders and site records. The CSV file opens in spreadsheet software. The PDF file gives a simple printable report. Use the example table to understand typical inputs before entering field data.

Field Accuracy

For best results, measure longitude carefully. Use signed values. East is positive, and west is negative. Enter magnetic variation only when using a compass. Keep the mount mast perfectly vertical. Set the polar axis first. Then set declination. Finally peak the dish on a strong satellite close to your local meridian. Record weather and cable condition during each test. Wet connectors and long coax runs can hide geometry mistakes. Recheck every clamp after final peaking and locking nuts.