NOVAS3.CioArray Method
Click or drag to resize

NOVAS3CioArray Method

Calaculate an array of CIO RA values around a given date

Namespace:  ASCOM.Astrometry.NOVAS
Assembly:  ASCOM.Astrometry (in ASCOM.Astrometry.dll) Version: (
public short CioArray(
	double JdTdb,
	int NPts,
	ref ArrayList Cio


Type: SystemDouble
TDB Julian date.
Type: SystemInt32
Number of Julian dates and right ascension values requested (not less than 2 or more than 20).
Type: System.CollectionsArrayList
An arraylist of RaOfCIO structures containing a time series of the right ascension of the Celestial Intermediate Origin (CIO) with respect to the GCRS.

Return Value

Type: Int16
 0 ... everything OK
 1 ... error opening the 'cio_ra.bin' file
 2 ... 'JdTdb' not in the range of the CIO file; 
 3 ... 'NPts' out of range
 4 ... unable to allocate memory for the internal 't' array; 
 5 ... unable to allocate memory for the internal 'ra' array; 
 6 ... 'JdTdb' is too close to either end of the CIO file; unable to put 'NPts' data points into the output object.

Given an input TDB Julian date and the number of data points desired, this function returns a set of Julian dates and corresponding values of the GCRS right ascension of the celestial intermediate origin (CIO). The range of dates is centered (at least approximately) on the requested date. The function obtains the data from an external data file.

How to create and retrieve values from the arraylist
Dim CioList As New ArrayList, Nov3 As New ASCOM.Astrometry.NOVAS3

rc = Nov3.CioArray(2455251.5, 20, CioList) ' Get 20 values around date 00:00:00 February 24th 2010
MsgBox("Nov3 RC= " &  rc)

For Each CioA As ASCOM.Astrometry.RAOfCio In CioList
    MsgBox("CIO Array " & CioA.JdTdb & " " & CioA.RACio)
See Also