The observational data served by ESASky covers ESA astronomy missions, some partner agency missions and surveys and some ground-based observatories. In all cases, the metadata and links to the products and archives have been curated in collaboration with the mission specialists. In the current release imaging data, spectra and light-curves are included. More products from other missions will continue to be included.

Currently ESASky provides access to data from the following ESA missions:

Data from the following missions from other data providers are also available:

​Additionally, data is also served from external Data Centres via the External Data Centres button. This feature is described here.



INTEGRAL/IBIS observations consist on a large number of individual exposures (science windows) around a target position.  For this reason and because of the large size of the IBIS field-of-view, it is unpractical to display the geometric footprints of all these science windows. Instead, ESASky only displays the central pointing position of each IBIS observation, each of which is linked to the full list of science windows associated with it.

The data are downloaded from the INTEGRAL science archive at the INTEGRAL Science Data Centre (ISDC) in Geneva (Switzerland). The current implementation links each observation to its corresponding set of science windows in the archive, which can therefore be downloaded as a group. It is however not possible to select more than one observation, because grouping several of them could result in a set of science windows that is too large to be handled correctly at this time.



The observations include public high-level Processing Pipeline System (PPS) products present in the XMM-Newton Science Archive (XSA). Detailed information on XMM-Newton products can be found in the XMM-Newton Science Archive Data Products Guide.

A brief description of the products provided by ESASky is given below. For more information about the mission please visit the XMM-Newton Science Operations Centre web pages.


The data included are the combined high-level image products from the three cameras (EPIC PN, EPIC MOS1, and EPIC MOS2) in the 0.2-12 keV energy band, updated weekly. For more information see the EPIC camera technical details page.

The selection criteria are based on the existence of a public EPIC high-level combined image. The mosaic sub-pointing products are excluded but the whole combined mosaic observations are included.

Observation footprints were obtained from the Sensitivity Map (OSNSMP) products associated to EPIC images. The sensitivity map gives the minimum source flux detectable by the point source detection task of the pipeline software when analysing EPIC images.

  • Data type: EPIC Observation Image (OIMAGE).
  • Energy Range: 0.2-12 keV.
  • Date of observations: From February 2000, updated regularly
  • Postcard preview filenames: P[obsid]EPX000OIMAGE8000.png
  • Science products filenames: P[obsid]EPX000OIMAGE8000.fits

IMPORTANT NOTE: There are 62 observations used as input for the XMM-Newton Epic HiPS map that are not linked yet in the application. This is due to the fact that these PPS products, the EPIC THREE COLOUR IMAGES, were generated  for the sky map by running the pps task etruecolor (xcolorcod-1.28) by XMM-Newton SOC (P.Rodriguez). These observations do not have a PPS EPIC combined Image although they do have one or several EPIC cameras in Image mode.


The Optical Monitor (OM) data in ESASky are public observations with at least one OM high-level image pipeline product, where individual OM sky images per filter are combined and North-aligned. Included in ESASky are the following OM Sky Image file types: RSIMAG Default-mode (RSIMAG), Full-frame low resolution (LSIMAG), Full-frame high resolution (HSIMAG), and User Defined (USIMAG).

  • Data type(s): OM Sky Combined Images (RSIMAG, LSIMAG, HSIMAG, USIMAG).
  • Passband(s): Optical (V, B, U), and Ultraviolet (UVW1, UVM2, UVW2).
  • Date of observations: from February 2000, updated regularly
  • Number of observations: from 970 (in filter V) to 4204 (in filter UVW1)
  • Postcard preview filenames: P[obsid]OMX000OIMAGE8000.png
  • Science product filenames:   P[obsid]OMX000OIMAGE8000.fits

Reflection Grating Spectrometer (RGS - spectroscopy)

Each of the two Reflection Grating Spectrometers (RGS) onboard XMM-Newton consists of an array of reflection gratings which diffracts the X-rays to an array of dedicated charge coupled devices (CCD) detectors, using an aperture of 5’ over the whole detector array (30’ diameter). 

The RGS instruments achieve high resolving power (150 to 800) over a range from 5 to 35 Å [0.33 to 2.5 keV] (in the first spectral order). The effective area peaks around 15 Å [0.83 keV] (first order) at about 150 cm2 for the two spectrometers. 

ESASky provides all spectra extracted within each aperture.

  • Data type: RGS Fluxed Spectrum
  • Energy Range: 0.2-12 keV
  • Date of observations: From February 2000, updated regularly
  • Postcard preview filenames: P[ObsID]RGX000FLUXED100[SourceNo].png 
  • Science products filenames: P[ObsID]RGX000FLUXED100[SourceNo].fits



The International Ultraviolet Explorer (IUE) was a joint project between ESA, NASA and the UK PPARC. The mission operated between  1978 and 1996 with three Echelle spectrographs: SWP, LWP and LWR (a fourth instrument, SWR, was never operational). The table below summarises the characteristics of all three instruments. 


Instrument Spectral coverage Sensitivity
SWP 1150-1980 Å  2 10-15 erg sec-1 cm-2 Å-1
LWP 1850-3350 Å 1 10-15 erg sec-1 cm-2 Å-1
LWR 1850-3350 Å 2 10-15 erg sec-1 cm-2 Å-1


In all cases, two apertures were available: a small circular aperture of 3’’ radius, and a large 10’’ x 20’’ rectangular aperture. In low-resolution mode, the resolution is ~ 0.6 nm, corresponding to resolving powers of R~250 at 150 nm and R~450 at 270 nm. In high-resolution mode, the resolution is ~ 0.02 nm, corresponding to resolving powers of R~7500 at 150 nm and R~13500 at 270 nm, respectively.

ESASky provides fully calibrated spectra from all three spectrographs, which are directly retrieved from the IU Newly Extracted Spectra (INES) archive, hosted at the Centro de Astrobiología (CAB) near Madrid (Spain).

  • Data type(s): INES spectra
  • Date of observations: from January 1978 to September 1996
  • Spectral range(s): 1150-1980 Å, 1850-3350 Å
  • Number of observations: 110033
  • Postcard previews: [Instrument][ObsID][Disp(L/H)][Aper(L/S)].FITS.png
  • Science products: [Instrument][ObsID][Disp(L/H)][Aper(L/S)].FITS


ESASky applies a filter on the HST archival data to show firstly all HST composite images (associations), then to show any single images (HST singleton) that are not part of any association.

  • Data type(s): Level 2/1 drizzled imaging, coronagraphy imaging, polarimetry imaging, 1D time resolved spectroscopy, 1D spectropolarimetry, 1D spectroscopy, 2D slit spectroscopy and 2D slitless spectroscopy.
  • Date of observations: From 1990, updated regularly
  • Passband(s): From near-ultraviolet to near-infrared; see the eHST documentation (at the bottom of the eHST help page).
  • Number of observations: 300,000+
  • Postcard previews:
        From the HST collection: OBSID_prev.jpg
        From the HLA collection:
        From the HLSP collection: HST_PROPOSALID_00_INSTRUMENT_CAMERA_FILTER_drz.fits
  • Science products:
        From the HST collection: OBSID_drz.fits (images), OBSID_<mode>.fits (spectra)
        From the HLA collection:
        From the HLSP collection: HST_PROPOSALID_00_INSTRUMENT_CAMERA_FILTER_drz.fits
  • Pipeline name: Drizzlepac/Astrodrizzle

THe HST Collection

The HST collection 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). These products are kept current by the HST Cache system described here.
  • 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.


  • Release: Data Release 10.0 (8th January 2018)

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). The HLA collection in the eHST contains enhanced image products for WFPC2 (produced by the CADC), ACS, NICMOS and WFC3 (produced by the STScI). Spectroscopy will be added very soon.

THe HLSP Collection

The High Level Science Products (HLSP) are community contributed, fully processed (reduced, co-added, cosmic-ray cleaned etc.) images and spectra that are ready for scientific analysis. Currently, ESASky only contains the HLSPs from GOODS North + South.

More information on the HLSPs can be found here.



CHEOPS is an ESA mission developed in partnership with Switzerland, with a dedicated consortium led by the University of Bern, and with important contributions from Austria, Belgium, France, Germany, Hungary, Italy, Portugal, Spain, Sweden and the UK. The satellite has a single payload comprising an ultra-high precision photometer covering the 330 - 1100 nm wavelength range in a single photometric band. Observations are made as part of the Guaranteed Time Observing Programme that is formulated by the CHEOPS Science Team and the Guest Observers Programme through which the Community at large can apply for CHEOPS time. The subset of CHEOPS data available through ESASky includes an example of a light  curve (the highest level data product produced by the automated data reduction pipeline) and the data reduction pipeline report for each public science observation.  These have been extracted from the CHEOPS Mission Archive which can be queried to retrieve selected metadata for all scientific observations made by CHEOPS (public and proprietary), as well as the full set of data products for all public data. CHEOPS light curves retain the imprint of the c. 98 minute satellite orbit, which introduces periodic systematics which in turn can be removed by de-trending. 

Metadata and data products displayed in ESASky include: 

  • Data type: CHEOPS light curve (extracted using the “optimal aperture”), Data reduction pipeline report .
  • Spectral Range: 330 - 1100 nm (visible - near-infrared).
  • Date of observations: From December 2019, updated regularly.
  • Science products filenames: CH_PR*_SCI_COR_Lightcurve_OPTIMAL_V.fits
  • Postcard preview filenames: *DataReduction*.pdf



The James Webb Space Telescope (JWST) is the largest optical or infrared observatory ever launched to space. Developed in a collaboration between NASA, ESA, and CSA, Webb observes the Universe in infrared light from its orbit at the Lagrangian point L2, 1.5 million km away from Earth.

Following launch, and after an initial commissioning phase of 6 months, the observatory has entered its regular science operations phase, during which approved observation programs will be performed. Scientific data is collected from a set of observer-created programs placed on a timeline of activities sent up to the spacecraft up to twice a day during operations. The products provided in ESASky are level 3 science products, not including comissioning data (use the ESASky Search interface of the eJWST archive to also view comissioning data).

A brief description of the products provided in ESASky is given below. For more information about the mission please visit the JWST ESA web pages and the STScI JWST web pages.

MIRI (IMAGING and Spectroscopy)

The Mid-Infrared Instrument (MIRI) provides JWST observers with coverage of mid-infrared wavelengths from 4.9 to 28.8 μm. Imaging can be obtained with 9 broad-band filters covering the wavelength ranges from 5.6μm to 25.5 μm. Spectroscopy can be obtained with a low spectral resolving power mode from 5-12 μm that includes both slitted and slitless options, or with a medium spectral resolving power integral field unit from 4.9 μm-28.8 μm. MIRI also contains one Lyot and three 4-quadrant phase mask coronagraphs that are optimized to the mid-infrared spectral region.

For more information about MIRI please see here and for detailed instrument information, please consult the MIRI JWST User Documentation (JDox).

NIRCam (Imaging, Spectroscopy AND Time-Series)

The Near-Infrared Camera (NIRCam) is JWST’s primary imager in the wavelength range from 0.6 to 5 μm. It consists of two, nearly identical, fully redundant modules, which point to adjacent fields of view on the sky and can be used simultaneously. Each module uses a dichroic to also observe simultaneously in both the short wavelength channel (0.6–2.3 μm) and long wavelength channel (2.4–5.0 μm).  

In addition to imaging with a wide range of narrow, medium, and broad filters, NIRCam also offers wide field slitless (grism) spectroscopy and coronagraphic imaging modes, as well as time-series and grism time-series observing modes for high accuracy photometric monitoring and spectrophotometric monitoring, respectively. NIRCam also obtains wavefront sensing measurements critical for periodic alignment and phasing of the segments of JWST's primary mirror.

For more information about NIRCam please see here and for detailed instrument information, please consult the NIRCam JWST User Documentation (JDox).

NIRISS (Imaging, Spectroscopy AND Interferometry)

The JWST Near-Infrared Imager and Slitless Spectrograph (NIRISS) provides unique observational capabilities between 0.6 and 5 μm that complement those available with NIRCam and NIRSpec. Its efficient, all-reflective design enables low-resolution, wide-field grism spectroscopy; medium-resolution grism spectroscopy optimized for applications requiring extreme spectrophotometric stability; aperture masking interferometry; and parallel imaging through filters matched to those available with NIRCam. 

For more information about NIRISS please see here and for detailed instrument information, please consult the NIRISS JWST User Documentation (JDox).

NIRSpec (Time-Series AND Spectroscopy: fixed slits, IFU & MOS)

JWST's Near-Infrared Spectrograph (NIRSpec) is a versatile spectroscopic instrument that operates in the 0.6 to 5.3 μm wavelength range. NIRSpec offers high throughput single object spectroscopy through fixed slits, spatially-resolved integral field unit spectroscopy, and a powerful multi-object spectroscopic mode using a micro-shutter assembly. NIRSpec also has a bright object time-series mode through a wide aperture that provides high throughput/high accuracy spectrophotometric monitoring capabilities to the astronomical community.

For more information about NIRSpec please see here and for detailed instrument information, please consult the NIRSpec JWST User Documentation (JDox).




The Infrared Space Observatory (ISO) was the world's first true orbiting infrared observatory launched in November 1995. It carried four scientific instruments: two spectrometers (SWS and LWS), an imaging photo-polarimeter (ISOPHOT) and a camera (ISOCAM). The only ISO imaging data provided through the ESASky interface are those from ISOCAM. Spectroscopic data from all four instruments are provided.

ISO spectroscopic observations were carried out with a variety of apertures and in raster mode, that is, performed by shifting the instrument aperture in the sky following a user-defined pattern. Since the information on the exact paintings within a raster was not easily retrievable, the ESASky footprints for these observations represent the overall raster shape, approximated by a rectangle. 

What follows is a brief description of the different data provided by ESASky. For more information on ISO observational data please visit the ISO Archive.

isocam (imaging and spectrophotometry) 

ISOCAM mapped selected areas in the sky in the spectral region from 2.5 to 18 micron with different spatial and spectral resolutions. 


ISOCAM provided imaging capabilities across a field of view of up to 3’ diameter. It consisted of two 32x32 pixels infrared detector arrays (used one at a time). The short wavelength channel operated between 2.5 and 5.2 microns, and the long wavelength channel, between 4 and 18 microns. Different configurations yielded spatial resolutions of 1.5, 3, 6 and 12’’ per pixel, translating into fields of view of 48’’x48’’, 96’’x96’’, 192’’x192’’ and 384’’x384’’, respectively. Broad and narrow-band filters were available.

  • Data type(s): CAM01 & CAM03 (Photometric imaging with ISOCAM; Scientifically validated)
  • Date of observations: from November 1995 to April 1998
  • Passband(s): 2.5-5.2 micron, 4-18 micron
  • Number of observations: 9868
  • Postcard previews: obsid_CAM_.jpg
  • Science products: CSLI_.fits
  • Pipeline name: CIA (ISOCAM Interactive Analysis)
  • Pipeline Version: AAC v10.3


ISOCAM also allowed to perform spectrophotometry, obtained by following a given sky region through a series of narrow-band images. 

  • Data type(s): CAM04 (Scientifically validated)
  • Date of observations: from November 1995 to April 1998
  • Passband(s): 2.5-18 micron
  • Number of observations: 
  • Postcard previews: obsid_CAM_.jpg
  • Science products: CSLI_.fits
  • Pipeline name: CIA (ISOCAM Interactive Analysis)
  • Pipeline Version: AAC v10.3

lws (spectroscopy)

The Long Wavelength Spectrometer (LWS) covered the spectral range between 43 and 197 micron at medium and high resolution. The spectral circular aperture had a diameter of 84’’; raster observations were also possible.

Grating mode, in which only the grating was used, provided moderate spectral resolving power of about 0.29 micron in the short-wavelength channels (SW1-SW5) and 0.6 micron in the long-wavelength channels (LW1-LW3, LW5) corresponding to a resolving power of between 100 and 300 depending on the wavelengths being investigated. The Fabry-Pérot mode, in which one of the two Fabry-Pérots was used in combination with the grating, provided high spectral resolving power between  8,000 and 10,000.

  • Data type(s): L01, L02, L03, L04 (Scientifically validated)
  • Date of observations: from November 1995 to April 1998
  • Passband(s): 45-196.8 micron
  • Number of observations: 
  • Postcard previews: obsid_LWS_.jpg
  • Science products:  L01, L02: lsph<ObsID>.fits; L03: lsan<ObsID>.fits; L04: lsp<ObsID>.fits
  • Pipeline Version: AAC v10.3

sws (spectroscopy)

The Short Wavelength Spectrometer (SWS) provided medium and high spectral resolution in the wavelength region 2.38-45.2 micron. Its two largely independent grating spectrometers had a spectral resolution of R~1000-2000, corresponding to a velocity resolution of approximately 150-300 km/s. By inserting Fabry-Pérot (FP) filters, one for the range 15-26 micron (with capability down to 11.4 micron at reduced resolution) and the other for the region 26-35 micron (with capability to 44.5 micron at reduced sensitivity), the resolution could be increased to R~30,000, or approximately 10 km/s.

  • Data type(s): S01, S02, S06, S07 (Scientifically validated)
  • Date of observations: from November 1995 to April 1998
  • Passband(s): 2.5-45 micron
  • Number of observations: 
  • Postcard previews: obsid_SWS_.jpg
  • Science products: S01: ssph<ObsID>.fits; S02, S06, S07: swaa<ObsID>.fits
  • Pipeline Version: AAC v10.3​

isophot (spectrophotometry)

ISOPHOT (PHT) was the imaging photo-polarimeter on board ISO. Its four principal modes were single detector element aperture photometry (3 - 120 microns), array imaging (40 - 240 microns), polarimetry (25, 170 microns) and spectrophotometry (2.5 - 12 microns). Only the spectrophotometric data are provided through ESASky.

The spectrophotometric mode was dedicated to obtaining low resolution spectra of broad spectral features such as dust and poliaromatic hydrocarbon (PAH) features. It used an aperture of 24’’x24’’; raster observations were also possible.

  • Data type(s): 
  • Date of observations: from November 1995 to April 1998
  • Passband(s): 2.5-240 micron
  • Postcard previews: obsid_PHOT_.jpg
  • Science products: psph<ObsID>.fits
  • Pipeline Version: AAC v10.3



The available Herschel data include all public observations from the HIFI, PACS and SPIRE instruments (including PACS/SPIRE parallel observations). The downloadable scientific data are Standalone Browse Products. A brief description of these products is given below. Click here for more information on the Herschel data products.

HIFI (spectroscopy)

The Heterodyne Instrument for the Far Infrared (HIFI) was a very high resolution heterodyne spectrometer able to electronically separate radiation of different wavelengths, giving a spectral resolution as high as R=107. The spectrometer was operated within two wavelength bands, from 157 to 212 micrometres and from 240 to 625 micrometres (490-1250 GHz and 1410-1910 GHz bands). In the case of HIFI, the products distributed as Standalone Browse Products are Level 2.5. 

  • Data type(s): Level 2.5/2.0 data products
  • Date of observations: From 2009 to 2013
  • Bands : 157-212 micron and 240-625 micron (490-1250 GHz and 1410-1910 GHz bands)
  • Number of observations:
  • Postcard previews: <obsid>-herschel.ia.obs.ObservationContent-*.jpg
  • Science products:
  • Pipeline name: HIPE
  • Pipeline Version: 14.1.0

pacs (imaging and spectroscopy)

The Photodetector Array Camera and Spectrometer (PACS) was a camera and low to medium resolution spectrometer for wavelengths in the range 55-210 µm. It employed four detector arrays, two bolometer arrays and two Ge:Ga photoconductor arrays. The bolometer arrays are dedicated for wideband photometry, while the photoconductor arrays are to be employed exclusively for spectroscopy with a resolution of a few thousand. PACS was operated either as an imaging photometer, or as an integral field line spectrometer. In the case of PACS, the products distributed as Standalone Browse Products are Level 2.5 scan maps created from pairs of scan and cross-scan observations; or, when Level 2.5 maps are not available, Level 2 highpass filter maps. 

  • Data type(s): Level 2.5/2.0 data products
  • Date of observations: From 2009 to 2013
  • Bands : 70, 100 and 160 micron
  • Number of observations: 8800+ (100/160 micron) to 9600+ (70/160 micron)
  • Postcard previews: <obsid>-herschel.ia.obs.ObservationContent-*.jpg
  • Science products: hpacs_25HPPJSMAP*.fits (level 2.5); hpacs<obsid>_20hpppmap*.fits (level 2)
  • Pipeline name: HIPE
  • Pipeline Version: 14.2.0

SPIRE (imaging and spectroscopy)

SPIRE was a camera and low to medium resolution spectrometer complementing PACS for wavelengths in the range 194-672 µm. It comprised of an imaging photometer and a Fourier Transform Spectrometer (FTS), both of which used bolometer detector arrays. There were a total of five arrays, three dedicated for photometry and two for spectroscopy. The SPIRE data provided in ESASky are Standalone Browse Products, Level 2 or Level 2.5 extended source calibrated maps, including SPIRE/PACS parallel mode observations.


  • Data type(s): Level 2.5/2.0 data products
  • Date of observations: From 2009 to 2013
  • Bands : 250, 350 and 500 micron
  • Number of observations: 1900+ per band
  • Postcard previews: <obsid>-herschel.ia.obs.ObservationContent-*.jpg
  • Science products:hspire<obsid>_20pxmp_*fits, hspire<obsid>_20ssopmp_*.fits (level 2); hspire*_25pxmp_*.fits (level 2.5)
  • Pipeline name: HIPE
  • Pipeline Version: 14.1.0



SUZAKU (jaxa / NASA)

The observations include all public imaging products present in the SUZAKU archive at DARTS. Detailed information on the SUZAKU mission and its products can be found in this site

  • Data type: Imaging Product (FITS)
  • Energy Range: 0.5-10 keV.
  • Date of observations: From August 2005 to May 2015
  • Number of observations: 2370
  • Postcard previews: ae[obsid]xis_0_im.gif
  • Science products: [obsid].fits
  • Pipeline Version: version 2.x.x.x 


Chandra (NASA)

The Chandra dataset includes all public observations (images and spectra), from August 1999 onwards, from the ACIS, LETG, HETG and HRC instruments, available in the Chandra Data Archive through Chaser. Detailed information on the Chandra mission and its products can be found at this website.

Advanced CCD Imaging Spectometer (ACIS - imaging and spectroscopy)

The Advanced CCD Imaging Spectrometer (ACIS) is an X-ray imager and moderate resolution spectrometer that operates in the energy range of 0.2 - 10 keV. ACIS has two arrays of CCDs, one (ACIS-I) optimised for imaging wide fields (16x16 arc minutes) the other (ACIS-S) optimised as a readout for the High Energy Transmision Grating (HETG). One chip of the ACIS-S (S3) is also used for on-axis (8x8 arc minutes) imaging and has the best energy resolution of the ACIS system. The data included in ESASky are the ACIS image and spectra. For more information see the ACIS Instrument information page and the Proposer's Observatory Guide.

  • Data type: ACIS calibration level 2 (imaging)
  • Energy Range: 0.2-10 keV.
  • Number of observations: 12,000+
  • Postcard preview filenames: acisf[obsid]N00[event file version]_full_img2.jpg (imaging)
  • Science products filenames: acisf[obsid]N00[event file version]_full_img2.fits (imaging)
  • Pipeline Version: DS 8.x.x to 10.x.x

High Resolution Camera (HRC - imaging and spectroscopy)

The High Resolution Camera (HRC) has two micro-channel plate imaging detectors, the HRC-I optimised for imaging and the HRC-S for spectroscopy. The HRC-I has the largest field of view aboard Chandra (31x31 arc minutes) and images over the range of 0.1 - 10 keV. The data included in ESASky are the HRC images and spectra. For more information see the HRC Instrument information page and the Proposer's Observatory Guide.

  • Data type: HRC calibration level 2 (imaging)
  • Energy Range: 0.1-10 keV.
  • Number of observations: 1900+
  • Postcard preview filenames: hrcf[obsid]N00[event file version]_full_img2.jpg (imaging)
  • Science products filenames: hrcf[obsid]N00[event file version]_full_img2.fits (imaging)
  • Pipeline Version: DS 8.x.x to 10.x.x

Low Energy Transmission Grating (LETG - spectroscopy)

The Low Energy Transmission Grating (LETG) provides the highest spectral resolving power (E/ΔE > 1000) on Chandra at low energies (0.07-0.15 keV, 80-175 Å) and moderate resolving power (E/ΔE ~ 20xλ) at higher energies (3-50 Å, 0.25-4.13 keV). The LETG comprises a grating assembly which intercepts and disperses flux from the mirrors. The HRC or ACIS can be used to read out the dispersed spectra. The LETG/HRC-S combination is used extensively for high resolution spectroscopy of bright, soft sources such as stellar coronae, white dwarf atmospheres and cataclysmic variables. For more information see the LETG Instrument information page and the Proposer's Observatory Guide.

  • Data type: ACIS calibration level 2 (spectra)
  • Energy Range: 0.07-4.13 keV.
  • Number of observations:
  • Postcard preview filenames: acisf/hrcf[obsid]N00[event file version]_full_pha2.jpg (spectra)
  • Science products filenames: acisf/hrcf[obsid]N00[event file version]_full_pha2.fits (spectra)
  • Pipeline Version: DS 8.x.x to 10.x.x

High Energy Transmission Grating (HETG - spectroscopy)

The High Energy Transmission Grating (HETG) is used for high resolution spectroscopy of bright sources in the range 0.4-10 keV (31-1.2 Å). The HETG has been used to measure Doppler velocities of orbiting systems, even as low as 50 km/s, and plasma outflow velocities from a few hundred to 10's of thousands of km/s. Because the HETG can clearly resolve lines from O to Fe-K, detailed line diagnostics can be applied. It is most commonly used with ACIS-S. The resolving power (E/ΔE) varies from ~800 at 1.5 keV to ~200 at 6 keV. For more information see the HETG Instrument information page and the Proposer's Observatory Guide.

  • Data type: ACIS calibration level 2 (spectra)
  • Energy Range: 0.4-10 keV.
  • Number of observations:
  • Postcard preview filenames: acisf/hrcf[obsid]N00[event file version]_full_pha2.jpg (spectra)
  • Science products filenames: acisf/hrcf[obsid]N00[event file version]_full_pha2.fits (spectra)
  • Pipeline Version: DS 8.x.x to 10.x.x

For more information about the mission please visit the Chandra X-ray Center web pages.



eROSITA (extended ROentgen Survey with an Imaging Telescope Array) is a wide-field X-ray telescope on-board the Russian-German "Spectrum-Roentgen-Gamma" (SRG) observatory, and it was developed under the leadership of the Max-Planck Institute for extraterrestrial Physics (MPE) in Germany (DE). eROSITA is a sensitive X-ray telescope capable of delivering deep, sharp images over very large areas of the sky in the energy range ~0.2-8 keV. The eROSITA telescope consists of seven identical Wolter-1 mirror modules. Each module contains 54 nested mirror shells to meet the required sensitivity. A novel detector system has been developed by MPE based on of the successful XMM-Newton pn-CCD technology.

The German eROSITA Consortium (eROSITA-DE) makes public the (German-led) observations obtained during the Calibration and Performance Verification (Cal-PV) program. This public data release is called eROSITA-DE Early Data Release (EDR) and can be accessed through ESASky. The Cal-PV program of the SRG mission took place between mid-September and mid-December 2019. During this Cal-PV phase, over one hundred individual pointings and field scans were performed with eROSITA as prime instrument, and around thirty different fields were been observed. Detailed information on eROSITA and its products can be found in the eROSITA-DE Science Portal

  • Data type: Imaging/Event list (FITS)
  • Energy Range: 0.2-10 keV.
  • Date of observations: EDR: mid-September to mid-December 2019
  • Number of observations: 174
  • Science products: [prefix]_[obsid]_[dataset code]_[dataset type]_[pipeline configuration].fits


AKARI (jaxa / ESA)

ESASky serves all pointed observations taken with the InfraRed Camera (IRC) of this mission, which are directly downloaded from DARTS. The IRC consisted of three independent camera systems, NIR, MIR-S and MIR-L, which observed the wavelength bands of 1.7-5.5 μm, 5.8-14.1 μm, and 12.4-26.5 μm, respectively. Each camera system had three filters available. NIR and MIR-S covered the same field of view (FoV), while MIR-L had a different one, which did not overlap with the NIR/MIR-S FoV. A brief description of the instrument and data products is given in this document

  • Data type: Imaging Product (FITS)
  • Wavelength Range: 12.4-26.5 μm
  • Date of observations: From May 2006 to November 2011
  • Number of observations: 8188
  • Postcard previews: N/A
  • Science products: [obid]_[filter]_long.fits
  • Pipeline Version: ircpipeline

For more information on the mission and data, visit the JAXA AKARI website or refer to the ESA AKARI pages.



The Spitzer Space Telescope operated from 2003 to 2020. The data integrated into ESASky come from the Spitzer Enhanced Imaging Products (SEIP), Cryogenic Release version 3.0. These are combined images ("Super Mosaics") for data from Spitzer's cryogenic mission, including all four bands (3.6, 4.5, 5.8, 8 microns) of the Infrared Array Camera (IRAC), and the 24 micron band of the Multiband Imaging Photometer for Spitzer (MIPS). The cryogenic mission operated from Dec 2003 – May 2009. The post-cryo mission included May 2009 through January 2020, but these data are not yet integrated into ESASky.

  • Data type: Imaging Product (FITS)
  • Instrument(s): IRAC and MIPS
  • Band(s): IRAC 1, 2, 3 and 4: 3.6 microns, 4.5 microns, 5.8 microns, 8 microns; MIPS 24 microns.
  • Observation mode(s): IRAC: Spitzer Enhanced Imaging Products (SEIP) Super Mosaics
  • Number of observations: IRAC1: 10949; IRAC2: 10944; IRAC3: 10946; IRAC4: 10949
  • Date of observations: From Dec 2003 to May 2009.

For more information on the mission and SEIP data, visit the IRSA page on Spitzer here.



The Atacama Large Millimeter/submillimeter Array (ALMA) observations and associated footprints available in ESASky include all public products present in the ALMA archive of the European Southern Observatory (ESO), from February 2011 onwards. Detailed information on the ALMA observatory and its products can be found in the ALMA website

  • Data type: Calibration level 2
  • Frequency Range: 84 to ~950 GHz
  • Date of observations: From February 2011 onwards
  • Number of observations: 65,000+
  • Science products: [project code][uid].tar (FITS)
  • Pipeline Version: Various versions of CASA and the ALMA Science Pipeline.