Dark Energy Camera (DECam)

DECam is a high-performance, wide-field CCD imager at the prime focus of the Blanco 4-m telescope at CTIO.   DECam imager contains 62 science CCDs with 520 megapixels and images 3 square degrees (2.2 degree wide field) at 0.27 arcsecond/pixel resolution.

DECam was built to carry out the Dark Energy Survey (DES) Project by the DES Collaboration, which is a Fermilab-led  international collaboration of over 120 scientists from 15 institutions and consortia in the USA, UK, Spain, Brazil and Germany.   DECam is an NOAO facility instrument, available to all users. The DES Collaboration, in exchange for the instrument and a community pipeline will receive 525 nights over 5 years to carry out the Dark Energy Survey. The project is funded by the DOE and NSF, the funding agencies of the UK, Spain, Brazil, and Germany, and contributions from the Collaboration institutions.

Documentation:

• READ THIS!: Safety precautions for operating DECam
• An Observing Cookbook for New Users
• Instrument characteristics -- focal plane characteristics, pixel orientation, pixel scale distortion map
• Tools -- all-sky camera, scripts editor, image manipulation
• Calibration Files -- crosstalk correction and bad pixel masks.
• Photometric calibration (standard stars)
• Filter transmission curve data and transmission plot, from Asahi.  (See FAQ if you plan white light observations (don't))
• A Community Pipeline operated by NOAO processes raw DECam images and calibration frames into single and stacked frames with astrometric and rough photometric solutions.  All data are served from the NOAO Science Archive.
• Exposure Time Calculator (Excel spreadsheet, by Darren DePoy and Alistair Walker). This ETC includes as-built optics transmissions, filter transmissions, CCD QE as a function of wavelength, and sky brightness at various lunar phases.  It should give reasonable estimates for stellar photometry with DECam.
• Known Problems
• Frequently Asked Questions

Latest News

• 2013 April 10:
  Exposure Time Calculator updated - now handles all lunar phases
• 2013 March 13:
  Tracking & Guiding are now no longer issues for the delivered image quality
  We’ll be optimizing the guider algorithm to improve star selection in crowded regions,  guide star recovery in clouded conditions, etc.   Use of  guider “auto” mode depends on having good pointing
  Pointing – there has been some improvement with bug fixes and new pointing models.   But rms across the sky is still ~ 60 arc sec, target 10 arc sec.
  The telescope seems more sensitive to wind buffeting, we are revising protocols for use of the wind blind and closing the windows.
• 2013 February 25-27 Engineering Run:
  The RA and declination servos were successfully re-optimized to compensate for telescope improvements, leading to an overall significant improvement in guiding in RA and declination.  Preliminary results show no RA or dec guiding oscillations, in all parts of the sky.  Open loop tracking was also improved--preliminary results show smooth behavior over the sky, max 1.0 arcsec/min (which is within specs).  

About DECam

• DECam is at CTIO
• Dark Energy Survey

CTIO Contacts

• DECam Instrument Scientist:  Alistair Walker
• Science support:   David James, Andrea Kunder, Tim Abbott, Katie Kaleida, Chris Smith

• Azooptics article, 13 September 2012: "Dark Energy Camera to Detect Subtle Effects of Weak Lensing"
• Scientific American article, 12 September 2012: "Cameras To Focus On Dark Energy"
• Nature news article, 12 September 2012: "Cameras To Focus On Dark Energy"
• Symmetry Magazine, 5 September 2012: :The Dark Energy Camera Opens Its Eyes"
• Economist article, 18 February 2012: "The Dark Side of the Universe"
• NPR article, 22 August 2011: "Giant Camera Will Hunt for Signs of Dark Energy"
• WIRED article, 18 November 2010: "570-Megapixel Camera Prepares to Hunt for Dark Energy"

CTIO DECam Support Pages (Internal Use Only)

CTIO DECam Support Staff for 2013A (Internal Use Only)