Dark Energy Camera (DECam)

DECam is a high-performance, wide-field CCD imager mounted at the prime focus of the Victor M. Blanco 4m Telescope at CTIO, with 62 science CCDs (60.5 useful) with 520 megapixels and images 3 square degrees (2.2 degree wide) field at 0.263 arcsecond/pixel resolution.  DECam is a facility instrument, available to all users.    DECam was built to carry out the Dark Energy Survey (DES) Project by the DES Collaboration, which finished observations in January 2019.   We can accommodate programs from small to large, and also those with special requirements such as synoptic and target of opportunity.   Most of the programs fit  within a "half night" organization, which provides a better match of program requirements to lunar phase than does whole night scheduling.  Note that observations are taken "classically", with astronomers present at the telescope, although we can also under pre-arranged conditions support remote observing from a permanent and tested remote observing facility.   We do not offer queue observing.    Please do not hesitate to contact us! (decam-help@ctio.noao.edu).



  • Data Handbook: The DECam Chapter of the Data Handbook (chapter 4) contains information not only about the instrument and observing system, but also covers the data format and the processing done by the DECam Community Pipeline and the resulting data products. 
  • A Community Pipeline operated by NSF's NOIR Lab processes raw community-time DECam images and calibration frames into single and stacked frames with astrometric and rough photometric solutions.  All data are served from the NOIRLab Astro Data Archive
  • DES Data Release 1 (DR1) is here
  • The DECam Legacy Survey (DECaLS) Data Releases are available here
  • The Astro DataLab also hosts both DES DR1 and DECaLS catalogs
  • For DES images we serve single-images (i.e. not stacks) as reduced by the DES pipeline, respecting the 12 month proprietary time.  DES only process and releases those images judged to be of survey quality.  Non-survey quality images may still be scientifically useful for some purposes. 
  • DES will issue final catalogs after completion of the survey (~2020-2021).
  • NEW! A guide for making custom stacked images, by F. Valdes




  • The last image for the Dark Energy Survey (DES) was taken on January 9, 2019!
  • Since early 2018 there is new narrow band (Halpha) filter available in DECam. Details here
  • DECam Community Science Workshop 2018 held in Tucson, AZ, May 21-22
  • 2016 December 29: During this night CCD S30 began working again!!   Since November 2013 when this CCD "failed" it has shown no stars, nothing but streaks.   The fault was proven to be inside the dewar, and was consistemt with losing a clock signal.  However since Dec 29 star images and flats look completely normal. The revival took place sometime between images 604976 and 605314.
  • 2016 March 9:  New version of the ETC (v7) is available with correction of an error in the calculation of the CCD read noise contribution to the total S/N. This was affecting mainly short exposures taken with bluer filters in dark conditions.
  • 2015 Dec. A new filter, N964, was installed in the DECam system on December 2015. This is a narrow-band filter made by Materion and funded by an international team with P.I. JunXian Wang of the University of Science and Technology, PRC. It is centered at 9640 A with a width of 95 A. The filter is available for use by NOAO and Chilean community scientists with prior authorization from the PI and his team. Please, contact us in advance if your are interested in using it.
  • 2015 Apr 2. Communicating DECam Exposures to Ignore to the NOIRLab Community Pipeline
  • 2015 March 7. New version (v6) of the ETC with changes in QE, mirror reflectivity and central wavelength of the u filter.
  • 2014 September 2. ETC updated to follow the real DECam PSF rather than a Gaussian
  • 2014 March 17.   A VR filter, covering 500-760 nm so approximately twice the bandpass of the SDSS filters, has been successfully installed.   Images are still being evaluated, but looks good!   Exposure failures due to the shutter aborting are a thing of the past, with the replacement of a drive motor.   And, the shutter and filter assembly interior axial surfaces have been painted with anti-reflection paint, and image contamination by bright stars just outside the FOV are greatly (factor 100?) attenuated.
  • 2013 December 17:  The Blanco dome encoder system has been replaced.  The new tape and reader provide accurate readings of the dome position (to better than one degree) and misalignments of telescope and dome should now be a thing of the past.
  • 2013 November 30:  CCD S30 is not working. Unlike the failure of N30 a year ago that was associated with over-illumination, S30 is exhibiting problems with one of its bias voltages.  It is not 100% sure whether the fault is with the CCD or associated electronics, tests are proceeding.  
  • 2013 October 28:  ETC updated to correct an incorrect value for the telescope collecting area, and also it now handles all lunar phases


CTIO Contacts


CTIO DECam Support Pages (Internal Use Only)

DECam PropIDs & Special Cases (Internal Use Only)

DECam Log of Configuration Changes and Events (Internal Use Only)