---
id: photutils
version: "3.0.0"
license: BSD-3-Clause
license_treatment: permissive
maintenance: active
---

# photutils — An Astropy package for source detection and photometry

License: permissive · Maintenance: active · Downloads: 164.0K/mo

## What it is and what it does

Photutils is an Astropy-affiliated Python library for detecting and measuring astronomical sources in images. It provides a suite of tools covering the full photometry workflow: background estimation and subtraction, star and source detection, aperture and PSF photometry, image segmentation, centroid calculation, radial profile extraction, and elliptical isophote fitting. The package is built on numpy and scipy for numerical computation and integrates tightly with Astropy's coordinate and unit systems, making it a standard choice for astronomical image analysis pipelines.

The library is actively maintained and supports current Python versions (3.11+). It includes compiled Cython extensions for performance-critical operations, available as pre-built wheels for common platforms. With no known security vulnerabilities, it is a mature and widely-used component of the astronomical Python ecosystem.

Use it for:

- Detect point sources and extended objects in survey images or deep field observations.
- Measure flux and magnitudes of stars and galaxies using aperture or PSF-fitting photometry.
- Estimate and subtract background in astronomical images for improved source detection.
- Segment and analyze morphology of galaxies or nebulae in multi-wavelength imaging.
- Extract radial profiles and fit isophotes to characterize source structure and properties.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Photutils provides tools for detecting and measuring astronomical sources in images, including background estimation, star finding, aperture photometry, PSF photometry, source segmentation, and isophote fitting.

Yes. Photutils is a well-maintained, actively developed library with no security issues, permissive licensing, and broad adoption in the astronomy community. The medium install friction from compiled extensions is standard for scientific Python packages and offset by pre-built wheels. Install it if you work with astronomical imaging data and need production-grade source detection or photometry tools.

## Install

pip install photutils
uv add photutils
poetry add photutils

## Installing photutils

Before you install: Medium install friction due to compiled Cython extensions, but actively maintained with recent releases and well-integrated with the Astropy ecosystem. Requires Python 3.11 or later.

License in practice: BSD-3-Clause permissive license allows use in most projects, including commercial and proprietary work, with minimal restrictions beyond attribution.

Quickstart:

pip install photutils

import photutils
from photutils.detection import find_peaks
from photutils.aperture import aperture_photometry
import numpy as np

# Detect sources and perform aperture photometry
sources = find_peaks(image_data, threshold=3.0)
phot = aperture_photometry(image_data, apertures)

Requires Python 3.11 or later; compiled wheels available for macOS (x86_64, arm64), Linux (x86_64), and Windows (x86_64), but installation from source requires a C compiler and Cython.

Verify before relying:

- Performance characteristics for real-time or large-scale survey pipelines.
- Specific version compatibility with other Astropy affiliated packages beyond core Astropy.
- Whether monthly download volume reflects active production use or broader adoption patterns.

## Package facts

- License: BSD-3-Clause (permissive)
- Python support: supports_current
- Install friction: medium
- Maintenance: active
- Downloads: 164.0K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

astronomical source detection, aperture photometry, PSF photometry, background estimation astronomy, image segmentation astronomy, star finding, astronomical image analysis, astronomy, image-analysis, photometry

[View on SkillFed](https://skillfed.io/packages/photutils) · [View on PyPI](https://pypi.org/project/photutils/)