DECam is a high-performance, wide-field CCD imager mounted 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 0.263 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.
- NOAO Data Handbook: The DECam Chapter of the NOAO 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.
- All DES science verification data (December 2012-February 2013) raw images are available from the NOAO Science Archive (NSA). This data has zero proprietary time.
- A Community Pipeline operated by NOAO 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 NOAO Science Archive.
- All Year 1 DES raw images are available now from the NSA.
- We will also serve single-images (i.e. not stacks) as reduced by the DES pipeline, respecting the 12 month proprietary time. DES will only process and release, those images judged to be of survey quality. Non-survey quality images may still be scientifically useful for some purposes. NOAO is evaluating whether to process and make available such non survey-quality images using the Community Pipeline, on request. N.B. This policy is provisional, and may change.
- DES will issue catalogs and stacks approximately mid-way through the survey (~2016) and after completion of the survey (~2018-2019).
Table with total throughput for u,g,r,i,z,Y filters (thanks to William Wester (DES Collaboration)). If you want the system throughput without the atmosphere, divide by the "atm" column.
Plot of total throughput
Plot of throughput without atmosphere
Filter transmission (area weighted response) from Asahi for u,g,r,i,z,Y and VR (plot)
- Properties of the VR filter
see FAQ if you are planning to observe with no filter (don´t!)
- 2015 Apr 2. Communicating DECam Exposures to Ignore to the NOAO 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 DECam Support Pages (Internal Use Only)
DECam PropIDs & Special Cases (internal use only)