Plate.FindCatalogStars() Method

Locate overlaying stars in the selected catalog

Syntax

Plate.FindCatalogStars()

The method syntax has these parts:

Remarks

Retrieves stars from the selected reference catalog into the CatalogStars collection. The WCS data must be valid before calling this method. The CatalogStarsValid flag is set when this completes, and the CatalogStars collection will contain PlateStar objects for each retrieved star. Retrieved stars include those that lie within the image area, plus a 30% wide border around the image area (adjustable via the advanced CatalogExpansion property). This allows for reasonable errors in the initial position estimate.

Using PinPoint to Look Up Stars from a Catalog

Since PinPoint is compatible with a wide variety of reference catalogs, you can use PinPpint simply as a tool for looking up reference stars in an area of the sky. To do this, you do not need to have an attached FITS image. You can manufacture an empty array in your code (differs depending on the language) then assign the array to the Plate.ImageArray property. Then assign values to the plate scales, equinox, projection type, etc. and call Plate.FIndImageStars(). See the example in VBScript below. If using JScript, you will need a VBArray not a native Javascript array. In C# (.net) you can use Array.CreateInstance() to make a compatible array. Here is an example in VBScript:

    Set PL = CreateObject("PinPoint.Plate")
    PL.Catalog = catalog type
    PL.CatalogPath = path to catalog
    '
    ' (see below, scale is 6 arcmin/pix)
    sz = (SkyDegrees * 10) - 1                        ' Upper index of image array for search area
    ReDim A(sz, sz)
    For i = 0 To sz
        For j = 0 To sz
            A(i,j) = CLng(0)
        Next
    Next
    PL.ImageArray = A
    PL.ArcsecPerPixelHoriz = 360                                ' 6 arcmin/pix
    PL.ArcsecPerPixelVert = 360
    PL.RollAngle = 0
    PL.Equinox = 2000 
    PL.ProjectionType = 1
    PL.CatalogExpansion = 0.0                                   ' No expansion!!!
    PL.RightAscension = whatever
    PL.Declination = whatever
    PL.FindCatalogStars
    ... etc ... read the collection