What coordinate systems are supported by this converter?

It supports Equatorial J2000, Equatorial B1950, Galactic (l/b), and Supergalactic (SGL/SGB) coordinate systems.

Can I input multiple coordinates at the same time?

Yes, you can input multiple coordinates by entering one object per line in the coordinates text area.

What formats are accepted for Equatorial coordinates?

You can use sexagesimal format (e.g., '05 34 31.94 +22 00 52.2') or decimal degrees (e.g., '192.85948 27.12825').

Which mathematical models are used for the conversions?

The tool uses the J2000 realization of the IAU 1958 system for galactic coordinates, the de Vaucouleurs (1976) system for supergalactic coordinates, and the IAU 1976 (Lieske) model for precession.

Are my coordinate inputs sent to an external server?

No, all coordinate conversions are calculated locally in your web browser for privacy and speed.

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Astronomy

Galactic / Equatorial Coordinate Converter

Convert astronomical positions between equatorial (RA/Dec J2000 and B1950), galactic (l/b), and supergalactic (SGL/SGB) coordinate systems. Accurate J2000 IAU 1958 galactic rotation, de Vaucouleurs supergalactic system, and IAU 1976 precession between epochs. Accepts sexagesimal (12h51m26s) or decimal-degree input and shows all four systems for each object.

Details

What this tool helps you do

A coordinate converter for amateur astronomers, astrophotographers, and observers:

From system — pick the system your input is in: Equatorial J2000 RA/Dec, Equatorial B1950 RA/Dec, Galactic l/b, or Supergalactic SGL/SGB.
To system — pick the target system (any of the four).
Coordinates — one object per line. For equatorial, give RA then Dec, e.g. 12 51 26.28 +27 07 41.7 (sexagesimal hours + degrees) or 192.85948 27.12825 (decimal degrees). For galactic/supergalactic, give longitude then latitude in degrees, e.g. 184.56 -5.78.
Output — each object is shown in the requested target system, plus an expandable table of all four systems for cross-reference.

The galactic conversion uses the modern J2000 realisation of the IAU 1958 system (the same matrix as SIMBAD, Gaia, and NASA/ADS), validated against the Crab Nebula and Sgr A*. Supergalactic coordinates follow de Vaucouleurs et al. (1976). J2000 ↔ B1950 uses the IAU 1976 (Lieske) precession model. All math runs locally.

Execution

Run this tool

Fill in the form, run the tool, and review the result in one place.

Prepared example runs

Click an example to fill the form automatically. File inputs still need an upload.

2 examples

Crab Nebula (M1): equatorial → galactic

A classic validation object — converts the Crab Nebula J2000 RA/Dec to galactic coordinates (expected l ≈ 184.56°, b ≈ -5.78°).

Galactic center → all systems

Sgr A* galactic coordinates (l=0, b=0) converted to equatorial and supergalactic, shown in all four systems.

Inputs

Set the required fields, then run the tool.

5 options

ContentPaste or type the main input values.1

Coordinates (one per line)textareaRequiredOne coordinate per line. For equatorial: RA then Dec. For galactic/supergalactic: longitude then latitude (degrees).

SettingsAdjust formats, ranges, numbers, and modes.4

From systemselectOptionalTo systemselectOptionalOutput formatselectOptionalDecimal placesnumberRequiredNumber of decimal places for decimal-degree output.

Result

Ready for a run

Run the tool to preview files, text, structured data, or streamed output here.

Samples

Galactic / Equatorial Coordinate Converter

What this tool helps you do

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Prepared example runs

Inputs

Result

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Prepared example runs

Inputs

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Key facts

Overview

When to use

How it works

Use cases

Examples

1. Converting Crab Nebula Coordinates to Galactic

2. Converting Galactic Center Coordinates to Equatorial J2000

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