The estimation of interstellar extinction is essential for all fields of astronomy, from stellar studies where we want to know the extinction towards a given object from its coordinates and distances (3D Models), to extragalactic astronomy field. In the latter case it is necessary to identify the contribution of the extinction of our Galaxy along the line of sight. In the last three decades many models and maps have been developed to describe the dust distribution in our Galaxy.

Our VO-Service called GALExtin estimates interstellar extinction based on both 3D models/maps and 2D maps available. The users only need to provide a list with coordinates (and distances) and to choose the model/map; GALExtin will then provide an output list with extinction determination. One of the main advantages of our VO-Service is ability to have available several models and maps developed in different languages (that use specific file annotations, some of them large ASCII tables), all wrapped in a unique tool.

For usage guidelines, acknowledgements and other issues, please see the page FAQs.


The simulations made by the users are at your risk, as well as the provided input files. Concerning the GALExtin estimates of Galactic interstellar extinction, Dr Eduardo Amôres has checked its consistency by comparing the results obtained with it with those obtained with the same programs running outside the GALExtin server. If you find any problem, please let us know (

Some of the others online tools and repositories

We want to emphasize the great work done by other authors who have developed tools that also provide interstellar extinction estimates. We certainly do not intend to force GALExtin estimates over their extinction values. Our main objective is to provide a collaborative VO-Service. Below, you can find links to several studies that also provide the interstellar extinction (2D and 3D) for a given line of sight.

List of available sites and services that estimate the interstellar extinction/reddening in our Galaxy.

- A tridimensional model of the Galactic interstellar extinction (Arenou et al. 1992)

- Galactic extinction calculator (Schlegel et al. 1998; Schlafly & Finkbeiner 2011) and coordinate transformation

- 2D maps based on DSS and 2MASS data (Dobashi et al. 2005; Dobashi 2011; Dobashi et al. 2013)

- Models for interstellar extinction in the Galaxy (Amôres & Lépine 2005)

- All-sky maps (Rowles & Froebrich 2009; Dobashi et al. 2005; Schlegel et al. 1998) and smaller-scale maps (Lombardi et al. 2006, 2008; Cambrésy 1999)

- BEAM extinction calculator (Gonzalez et al. 2011, 2012)

- RJCE two-dimensional extinction maps

- A map of dust reddening to 4.5 kpc from Pan-STARRS1 (Schlafly et al. 2014)

- Spanish Virtual Observatory (VO) extinction map (Morales-Durán et al. 2015)

- A three-dimensional map of Milky Way dust (Green et al. 2015, 2018, 2019)

- Dustmaps: A PYTHON interface for maps of interstellar dust (Green 2018)

- On Galactic density modelling in the presence of dust extinction (Bovy et al. 2016)

- A new, large-scale map of interstellar reddening derived from H I emission (Lenz et al. 2017)

- Structuring by Inversion the Local Interstellar Medium (Lallement et al. 2014; Capitanio et al. 2017)

- Gaia/2MASS: 3D dust extinction map (Lallement et al. 2019)

- Milky Way Dust: Bovy et al. (2015)

- Dust in three dimensions in the Galactic plane (Hanson et al. 2016)

- STARHORSE: a Bayesian tool for determining stellar masses, ages, distances, and extinctions for field stars (Queiroz et al. 2018)

- A color-excess extinction map of the southern Galactic disk from the VVV and GLIMPSE surveys (Soto et al. 2019)

List of repositories and references.

- Repository of a 3D extinction map of the northern Galactic plane based on IPHAS photometry (Sale 2012; Sale et al. 2014)

- Repository of photometric extinctions and distances (Chen et al. 2014)

- The Planck Dust Model Page

- 3D map of reddening and interstellar extinction (Gontcharov, 2017)

- Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia-DR2 stars brighter than G = 18 (Anders et al. 2019)

- Three-dimensional interstellar dust reddening maps of the Galactic plane (Chen et al. 2019)

- Gaia DR2 giants in the Galactic dust – II. Application of the reddening maps and models (Gontcharov and Mosenkov, 2020)

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