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MegaPrime Elixir Master Detrend Image Query Help


General Description

This form can be used by registered CFHTLS users to browse the catalog of MegaPrime Elixir master detrend images. In Elixir parlance, the calibration process of removing instrumental signatures such as bias levels, dark currents, flat-field variations and fringing from raw science images is known as "detrending" the images. Master calibration images are called master "detrend" images, and processed science images are called "detrended" images. One of the major advantages of Elixir is the ability to use all of the data from a given camera run to produce high-quality master calibration images. Details on the creation of these calibration images can be found on the Elixir Master Detrend page. The following types of master calibration images are produced by the Elixir system: bias, dark, mask, flat-field, fringe, fringe points, and scatter light. Queries can be executed based upon master detrend image constraints.

Master Detrend Image Constraints

Field Name Description
Detrend Image Name The master detrend image name. Dataset names for master detrend images are of the form CRUNID.TYPE.FILTER|EXPTIME.VERSION where CRUNID is the camera run ID, TYPE is the detrend type (e.g, flat), FILTER is the filter used when TYPE=flat,modes,fringe,frpts, scatter, EXPTIME is the exposure time when TYPE = bias, dark and mask, and VERSION is a version number to force the image names to be unique.
Camera run ID Identification code for camera run during which observation was taken. The camera run ID uniquely identifies a given period of time during which MegaPrime is mounted on the telescope. Example: 01Ak01 denotes the period between 2001/01/27 to 2001/02/06. A camera run can therefore encompass many observing runs. The full list of camera run IDs can obtained from the MegaPrime camera run ID page at CFHT.
Public Release Date The UT date of the public release of the master detrend image. Should in principle be the same as the creation date.
Validity Start Time Start time of the period for which the master detrend image is valid.
Validity Stop Time Stop (end) time of the period for which the master detrend image is valid. Unless otherwise specified, a master detrend image should never be applied to raw science images taken outside of the period bounded by its validity start and stop times.
Exposure Time Exposure time in seconds for master detrend images of type bias, dark, and mask.
Filter Filter used for master detrend images of type flat, modes, fringe, frpts, and scatter.
Detrend Type Type of master detrend image. Possible choices are bias, dark, mask, flat, modes, fringe, frpts (fringe point map) and scatter (light).
Image Version Version number to force master detrend image names to be unique.
CCD Info Name or ID number of CCD detector. Applies only to master detrend image in SPLIT format. While all MegaPrime master detrend images should be MEF images, many CFH12k detrend images are not. This image property is thus required to be able to include both MegaPrime and CFH12k master detrend images in the same catalog.
Image Mode Mode of master detrend image. The mode specifies the image in multi-extension FITS (MEF) format or in SPLIT format. While all MegaPrime master detrend images should be MEF images, many CFH12k detrend images are not. This image property is thus required to be able to include both MegaPrime and CFH12k master detrend images in the same catalog.
Elixir Version Elixir version number used to create master detrend image.
FLIPS Version FLIPS version number used to create master detrend image.