<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> <!--Converted with LaTeX2HTML 98.1p1 release (March 2nd, 1998) originally by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds * revised and updated by: Marcus Hennecke, Ross Moore, Herb Swan * with significant contributions from: Jens Lippmann, Marek Rouchal, Martin Wilck and others --> <HTML> <HEAD> <TITLE>Equinox</TITLE> <META NAME="description" CONTENT="Equinox"> <META NAME="keywords" CONTENT="vol2"> <META NAME="resource-type" CONTENT="document"> <META NAME="distribution" CONTENT="global"> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> <LINK REL="STYLESHEET" HREF="vol2.css"> <LINK REL="previous" HREF="node558.html"> <LINK REL="up" HREF="node555.html"> <LINK REL="next" HREF="node560.html"> </HEAD> <BODY > <!--Navigation Panel--> <A NAME="tex2html8515" HREF="node560.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="icons.gif/next_motif.gif"></A> <A NAME="tex2html8512" HREF="node555.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="icons.gif/up_motif.gif"></A> <A NAME="tex2html8508" HREF="node558.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="icons.gif/previous_motif.gif"></A> <A NAME="tex2html8514" HREF="node1.html"> <IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="icons.gif/contents_motif.gif"></A> <BR> <B> Next:</B> <A NAME="tex2html8516" HREF="node560.html">Optional stellar data</A> <B> Up:</B> <A NAME="tex2html8513" HREF="node555.html">Required stellar data</A> <B> Previous:</B> <A NAME="tex2html8509" HREF="node558.html">Declination</A> <BR> <BR> <!--End of Navigation Panel--> <H3><A NAME="SECTION003221400000000000000"> Equinox</A> </H3> Because precession is a large effect, we must know the equinox to which these coordinates refer. Although this is usually a constant for a whole table, and so might be stored in a descriptor, observers may want to use lists of program stars compiled from heterogeneous sources. Therefore, the year of the equinox must be stored in a separate column of Real*4 values, with the label EQUINOX. This column is easily created for a star catalog with a single equinox date using the <TT>COMPUTE/TABLE</TT> <I>tablename</I> <TT>:EQUINOX =</TT> <I>year</I> command. A format of F7.1 is satisfactory. <P> <BR> <DIV ALIGN="CENTER"><A NAME="30030"> </A> <TABLE> <CAPTION><STRONG>Table:</STRONG> Columns for star-catalog table files</CAPTION> <TR><TD> <DIV ALIGN="CENTER"> <TABLE CELLPADDING=3 BORDER="1" ALIGN="CENTER"> <TR><TD ALIGN="LEFT">Column Label</TD> <TD ALIGN="CENTER">Contents</TD> <TD ALIGN="CENTER">Units</TD> <TD ALIGN="LEFT">Variable Type</TD> <TD ALIGN="LEFT">Format</TD> <TD ALIGN="CENTER">Req'd?</TD> </TR> <TR><TD ALIGN="LEFT"><TT> OBJECT</TT></TD> <TD ALIGN="CENTER">Object name</TD> <TD ALIGN="CENTER"> </TD> <TD ALIGN="LEFT">C*32 string</TD> <TD ALIGN="LEFT">A32</TD> <TD ALIGN="CENTER">Y</TD> </TR> <TR><TD ALIGN="LEFT"><TT> RA</TT></TD> <TD ALIGN="CENTER">Right Ascension</TD> <TD ALIGN="CENTER">degrees</TD> <TD ALIGN="LEFT">R*4 real</TD> <TD ALIGN="LEFT">R11.6</TD> <TD ALIGN="CENTER">Y</TD> </TR> <TR><TD ALIGN="LEFT"><TT> DEC</TT></TD> <TD ALIGN="CENTER">Declination</TD> <TD ALIGN="CENTER">degrees</TD> <TD ALIGN="LEFT">R*4 real</TD> <TD ALIGN="LEFT">s12.6</TD> <TD ALIGN="CENTER">Y</TD> </TR> <TR><TD ALIGN="LEFT"><TT> EQUINOX</TT></TD> <TD ALIGN="CENTER">Equinox date</TD> <TD ALIGN="CENTER">years</TD> <TD ALIGN="LEFT">R*4 real</TD> <TD ALIGN="LEFT">F7.1</TD> <TD ALIGN="CENTER">Y</TD> </TR> <TR><TD ALIGN="LEFT"><TT> MUALPHA</TT></TD> <TD ALIGN="CENTER">Annual p.m. in R.A.</TD> <TD ALIGN="CENTER">sec/y</TD> <TD ALIGN="LEFT">R*4 real</TD> <TD ALIGN="LEFT">F7.4</TD> <TD ALIGN="CENTER">N</TD> </TR> <TR><TD ALIGN="LEFT"><TT> MUDELTA</TT></TD> <TD ALIGN="CENTER">Annual p.m. in Dec.</TD> <TD ALIGN="CENTER">arcsec/y</TD> <TD ALIGN="LEFT">R*4 real</TD> <TD ALIGN="LEFT">F7.3</TD> <TD ALIGN="CENTER">N</TD> </TR> <TR><TD ALIGN="LEFT"><TT> EPOCH</TT></TD> <TD ALIGN="CENTER">Position date</TD> <TD ALIGN="CENTER">years</TD> <TD ALIGN="LEFT">R*4 real</TD> <TD ALIGN="LEFT">F5.0</TD> <TD ALIGN="CENTER">N</TD> </TR> <TR><TD ALIGN="LEFT"><TT> SPTYPE</TT></TD> <TD ALIGN="CENTER">Spectral type</TD> <TD ALIGN="CENTER"> </TD> <TD ALIGN="LEFT">C*15 string</TD> <TD ALIGN="LEFT">A14</TD> <TD ALIGN="CENTER">N</TD> </TR> <TR><TD ALIGN="LEFT"><TT> MAG</TT></TD> <TD ALIGN="CENTER">Approx. mag.</TD> <TD ALIGN="CENTER"> </TD> <TD ALIGN="LEFT">C*11 string</TD> <TD ALIGN="LEFT">A11</TD> <TD ALIGN="CENTER">N</TD> </TR> <TR><TD ALIGN="LEFT"><TT> COMMENT</TT></TD> <TD ALIGN="CENTER">Comment</TD> <TD ALIGN="CENTER"> </TD> <TD ALIGN="LEFT">C*32 string</TD> <TD ALIGN="LEFT">A32</TD> <TD ALIGN="CENTER">N</TD> </TR> </TABLE></DIV> <A NAME="tbl:star-cat-cols"> </A></TD></TR> </TABLE> </DIV> <BR> <P> <HR> <!--Navigation Panel--> <A NAME="tex2html8515" HREF="node560.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="icons.gif/next_motif.gif"></A> <A NAME="tex2html8512" HREF="node555.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="icons.gif/up_motif.gif"></A> <A NAME="tex2html8508" HREF="node558.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="icons.gif/previous_motif.gif"></A> <A NAME="tex2html8514" HREF="node1.html"> <IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="icons.gif/contents_motif.gif"></A> <BR> <B> Next:</B> <A NAME="tex2html8516" HREF="node560.html">Optional stellar data</A> <B> Up:</B> <A NAME="tex2html8513" HREF="node555.html">Required stellar data</A> <B> Previous:</B> <A NAME="tex2html8509" HREF="node558.html">Declination</A> <!--End of Navigation Panel--> <ADDRESS> <I>Petra Nass</I> <BR><I>1999-06-15</I> </ADDRESS> </BODY> </HTML>
