• Image search page 
• Image cutout service 
• Scrollable images 

• Introduction 
• Search instructions 
• Data description 
• Stacking procedure 
• Checks on astrometry 
• Checks on photometry 
• Caveats 
• The ugriz filter set 

• MegaCam Graphical
  Search Tool
• CFHT science archive
• Stephen Gwyn's
  CFHTLS pages

• MegaPipe Paper 
• CFHT 
• Elixir pre-processing 
• SExtractor 
• SWarp 

This page documents the MegaPipe image search page.

• Enter search criteria in the form: Fill in the boxes and/or select from the menus. Leaving an entry blank means no constraint on that parameter. If you leave everything blank, you will get all the image groups.
• Click the "Search" button

• Object name:
  Name of the object: "M31" or "D3" or similar. Case insensitive.
• RA:
  Either in sexigesimal (10 30 43.5) hours or decimal degrees (157.6813). In 2000.0 coordinates.
• Dec:
  Either in sexigesimal (10 30 43.5) degrees or decimal degrees (10.5121). In 2000.0 coordinates.
• Search box:
  This is the maximum rectilinear distance between the search centre (specified by RA and Dec above) and the centre of an image. It allows for the cos(Dec) term.
• Name resolver:
  This parameter affects how searches on Object Name are handled. To find stacks based on the object name as given in the header of the original images, select "CFHT". Anything not in the header of the original image will not be found. If you select "Simbad", the object name will be resolved to RA and Dec coordinates by the Simbad astronomical database. Groups with RA and Dec coordinates of the object will be returned.

• Required?:
  If you want the group to contain an image in a certain band, set the "Required" to "Yes". If you don't need a certain band, set it to "No".
• Total exposure time:
  This is the sum of the exposure times of the input images in this filter.
• Number of input exposures:
  This the total number of input exposures that went into the image stacks in this filter.
• Limiting magnitude:
  This refers to the 5-sigma point source limiting magnitude in this filter.
• Image quality:
  The "seeing" of the image stack in this filter. This is the FHWM in arcseconds.

• Order by:
  The sorting order.
• Number of rows returned:
  Records beyond this limit will not be returned.
• Direct links to data?:
  If set to "Yes", the direct links to the images, weight maps and catalogues will be returned. If set to "No", these links will be omitted. These makes the table that is returned more readable, but means that users have click through to the indivdual group web pages to get the data.