Archive contents

All the HST observations currently available in the EHST are being synchronised with the MAST services for HST reprocessed public data and corresponding metadata, as a result of the collaboration between the partners STScI, CADC and ESAC, within the common HST Consolidation of Pipelines project. The HST archive at ESAC/ESA contains data from the following Hubble collections and catalogues:

Details on the collections and catalogues are given below. Please note that the Hubble Legacy Archive (HLA) collection will be added again very soon, we apologise for any inconvenience.

The HST Collection

The HST collection in the eHST is the standard HST archive content and contains the following:

  • All public (non-proprietary) HST data.
  • The standard HST archive products from the active instruments (ACS, COS, STIS, WFC3).
  • Data from legacy instruments (FOC, FOS, HRS, NICMOS, WFPC, WFPC2). These data have gone through a final calibration run and are not foreseen to change anymore.

Detailed information on the data produced by each instrument aboard the Hubble Space Telescope can be found in the official HST Instrument Handbooks, on the main HST Documentation page.

The Hubble Legacy Archive (HLA) Collection

  • Release: Data Release 10.1 (5 July 2018)

The HLA is designed to optimize science from the Hubble Space Telescope by providing online, enhanced Hubble products and advanced browsing capabilities. The HLA is a joint project of the Space Telescope Science Institute (STScI), the Space Telescope European Coordinating Facility (ST-ECF), and the Canadian Astronomy Data Centre (CADC).

See here for more HLA information.

Hubble Advanced Products (HAP)

Hubble Advanced Products (HAP) have begun to be produced by MAST, STScI in the HST data pipeline, from mid December 2020 onwards, and are made available in the eHST archive as they are produced in the pipeline. These first HAPs are ACS and WFC3 Hubble Legacy Archive (HLA)-style mosaics comprising the data from a single HST visit which are aligned to a common astrometric reference frame. It is anticipated that it will take roughly one to two months before all the archival data have been processed to create mosaic products.

Three levels of products are available as part of the first release:

  • Exposure level products contain data from a single HST exposure.
  • Filter level products are produced from all exposures in a visit with a common filter.
  • Total level products combine all exposures from a visit and are intended as a detection image for producing catalogs.

See here for more HAP information.

Hubble Advanced Spectroscopic Products (HASP)

The HASP program, developed by the Space Telescope Science Institute, revolutionizes the utilization of the Mikulski Archive for Space Telescopes (MAST), providing high-quality one-dimensional spectra for Hubble Space Telescope (HST) spectroscopic data. HASP offers robust coadded and combined products for nearly every Cosmic Origins Spectrograph (COS) and Space Telescope Imaging Spectrograph (STIS) spectrum, covering over 3200 programs and 64000 input datasets in MAST.

The ultimate goal of HASP is to simplify access to HST spectroscopic data by providing high-quality 1-D spectra that are both robust and flexible.

See here for more HASP information.

Hubble Spectroscopic Legacy Archive (HSLA)

While HASP provides visit-level and program-level coadds of 1-D spectra for both COS and STIS, the Hubble Spectroscopic Legacy Archive (HSLA) performs two additional steps. First, it combines data from multiple observing programs, instruments, and gratings to create spectral products with the highest possible signal-to-noise ratio and wavelength coverage. Second, it performs automatic target classification, enabling searches based on object classification as well as by target name.

See here for more HSLA information.

High Level Science Products (HLSP)

Since March 2026, the eHST archive provides access to the following HST High Level Science Products (HLSP):

CANDELSNIRWL: CANDELS NIRWL F160W Mosaics. The NIRWL team has prepared new mosaics covering the CANDELS fields: the UltraDeep Survey (UDS), GOODS-South (GS), GOODS-North (GN), the Extended Groth Strip (EGS), and the Cosmological Evolution Survey (COSMOS) in the HST WFC3/IR F160W filter. The mosaics are drizzled to a pixel scale of 0.05″ using a Gaussian kernel and are aligned to the Gaia DR3 catalog to ±0.02 arcsec, including proper motion corrections. These mosaics have been corrected for systematic astrometric misalignments present in previous versions and are designed to enable weak lensing analyses and searches for large-scale overdensities.

CLASSY: COS Legacy Archive Spectroscopic Survey. A Hubble Space Telescope treasury survey using the Cosmic Origins Spectrograph (COS) to construct a high-quality, high-resolution far-ultraviolet spectral database of 45 nearby star-forming galaxies. The survey combines archival and new HST observations to produce more than 600 spectra, sampling galaxies selected to span a wide range of properties similar to those seen at high redshift. The CLASSY spectral atlas contains a suite of emission and absorption features that enable investigations of the massive stellar population properties, the physical properties of large-scale outflows that regulate star formation, and the chemical abundance patterns of the gas and stars, and provide a benchmark dataset for interpreting rest-frame UV observations of distant galaxies.

CLUES: Clusters in the UV as Engines. An HST medium-size program providing FUV spectroscopy of 20 young star clusters in local galaxies (less than 16 Mpc away). All the CLUES star clusters are very young (<50 Myr) and massive (> 104 Msun), are hosted in galaxies that are part of the Hubble treasury program Legacy ExtraGalactic Uv Survey (LEGUS), and typically have two clusters observed per galaxy at different distances from the galactic center. The survey enables measurements of stellar population properties, stellar feedback from winds and supernovae, and the kinematics of outflowing gas through analysis of interstellar absorption lines in the FUV.

NLR-AGN: [O III] Imaging of Narrow Line Region Outflows in Nearby Active Galaxies. An HST programme providing new [O III] and continuum images of 12 Seyfert galaxies with existing long-slit STIS spectra. The sample spans a range of luminosity, black hole mass, and Eddington ratio, enabling studies of outflows in AGN narrow-line regions on parsec to kiloparsec scales. These products increase the legacy value of the archival STIS dataset for NLR studies.

ROCKY-WORLDS: Rocky Worlds Director's Discretionary Time (DDT) Program. Rocky Worlds is a joint JWST and HST DDT program implementing key recommendations from the Working Group on Strategic Exoplanet Initiatives with HST and JWST, including a 500-hour DDT JWST exoplanet program . The program's main objectives are to search for evidence for atmospheres on rocky exoplanets orbiting M-dwarfs via secondary eclipse measurements at 15 um using the MIRI instrument, as well as to characterize the stellar UV properties with HST.

SCYLLA: Named after the multi-headed monster from the myth of Ulysses, Scylla is an HST pure-parallel imaging survey of the stellar populations, interstellar medium, and star formation in the Large and Small Magellanic Clouds, complementing the ULLYSES spectroscopic programme. Observations were obtained with WFC3, providing broad photometric coverage from the near-UV to the near-infrared, with all fields imaged in at least the F475W and F814W filters and many fields spanning up to seven filters. The first data release includes 96 fields (48 in each of the LMC and SMC) observed over 342 orbits, reaching depths below the ancient main sequence turnoff. The HLSPs provide imaging and photometric catalogues, representing the widest-area HST photometric coverage of the Magellanic Clouds to date.

Hubble Source Catalog (HSC)

The Hubble Source Catalog is a combination of all the visit-based source lists in the Hubble Legacy Archive (HLA) into a single catalogue and is designed to optimize science from the Hubble Space Telescope by combining the tens of thousands of visit-based source lists in the Hubble Legacy Archive (HLA) into a single master catalog.

The HSC v3 contains members of the WFPC2, ACS/WFC, WFC3/UVIS and WFC3/IR Source Extractor source lists from HLA version DR10 (data release 10). The cross-matching process involves adjusting the relative astrometry of overlapping images so as to minimize positional offsets between closely aligned sources in different images. After correction, the astrometric residuals of cross-matched sources are significantly reduced, with median errors less than 8 mas. The absolute astrometry is calibrated using Gaia DR1, Pan-STARRS, SDSS, and 2MASS as the astrometric backbone for initial corrections. In addition, the catalog includes source nondetections. The cross-matching algorithms and the properties of the initial (Beta 0.1) catalog are described in Budavari & Lubow (2012), and the Version 1 catalog is described in Whitmore et al. (2016).

Version 3 includes (see here for more details):

  • There are approximately 25% more ACS source lists and almost twice as many WFC3 source lists compared with HSC v2.
  • The source list photometric quality is significantly improved.
  • Improved astrometric calibration is based on the Gaia DR1 catalog. Shifts up to 100 arcsec have been correctly identified. 94% of the fields have matches to an external astrometric reference catalog.
  • The scatter in magnitudes is measured using the median absolute deviation (MAD) of the differences from the median magnitude for more robust estimates.

Hubble Catalog of Variables (HCV)

The Hubble Catalog of Variables (HCV) is the first full, homogeneous, catalog of variable sources found in the Hubble Source Catalog (HSC), which is built out of publicly available images obtained with the WFPC2, ACS and WFC3 instruments onboard the Hubble Space Telescope. The HCV is the deepest catalog of variables available. It includes variable stars in our Galaxy and nearby galaxies, as well as transients and variable active galactic nuclei. In total, the HCV includes 84,428 candidate variable sources (out of 3.7 million HSC sources that were searched for variability) with V ≤ 27 mag; for 11,115 of them the variability is detected in more than one filter. The data points in a light curve range from 5 to 120, the time baseline ranges from under a day to over 15 years, while ∼8% of variables have amplitudes in excess of 1 mag.

For more details, see About the Hubble Catalog of Variables.