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diff --git a/src/slalib/sun67.htx/node4.html b/src/slalib/sun67.htx/node4.html new file mode 100644 index 0000000..81c9586 --- /dev/null +++ b/src/slalib/sun67.htx/node4.html @@ -0,0 +1,131 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"> +<!--Converted with LaTeX2HTML 97.1 (release) (July 13th, 1997) + 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 Lippman, Marek Rouchal, Martin Wilck and others --> +<HTML> +<HEAD> +<TITLE>Example Application</TITLE> +<META NAME="description" CONTENT="Example Application"> +<META NAME="keywords" CONTENT="sun67"> +<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="sun67.css"> +<LINK REL="next" HREF="node5.html"> +<LINK REL="previous" HREF="node3.html"> +<LINK REL="up" HREF="node2.html"> +<LINK REL="next" HREF="node5.html"> +</HEAD> +<BODY > +<BR> <HR> +<A NAME="tex2html285" HREF="node5.html"> +<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next_motif.gif"></A> +<A NAME="tex2html283" HREF="node2.html"> +<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up_motif.gif"></A> +<A NAME="tex2html277" HREF="node3.html"> +<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="previous_motif.gif"></A> <A HREF="sun67.html#stardoccontents"><IMG ALIGN="BOTTOM" BORDER="0" + SRC="contents_motif.gif"></A> +<BR> +<B> Next:</B> <A NAME="tex2html286" HREF="node5.html">Scope</A> +<BR> +<B>Up:</B> <A NAME="tex2html284" HREF="node2.html">INTRODUCTION</A> +<BR> +<B> Previous:</B> <A NAME="tex2html278" HREF="node3.html">Purpose</A> +<BR> <HR> <P> +<P><!--End of Navigation Panel--> +<H2><A NAME="SECTION00022000000000000000"> +Example Application</A> +</H2> +Here is a simple example of an application program written +using SLALIB calls: +<P><PRE> + PROGRAM FK4FK5 + * + * Read a B1950 position from I/O unit 5 and reply on I/O unit 6 + * with the J2000 equivalent. Enter a period to quit. + * + IMPLICIT NONE + CHARACTER C*80,S + INTEGER I,J,IHMSF(4),IDMSF(4) + DOUBLE PRECISION R4,D4,R5,D5 + LOGICAL BAD + + * Loop until a period is entered + C = ' ' + DO WHILE (C(:1).NE.'.') + + * Read h m s d ' " + READ (5,'(A)') C + IF (C(:1).NE.'.') THEN + BAD = .TRUE. + + * Decode the RA + I = 1 + CALL sla_DAFIN(C,I,R4,J) + IF (J.EQ.0) THEN + R4 = 15D0*R4 + + * Decode the Dec + CALL sla_DAFIN(C,I,D4,J) + IF (J.EQ.0) THEN + + * FK4 to FK5 + CALL sla_FK45Z(R4,D4,1950D0,R5,D5) + + * Format and output the result + CALL sla_DR2TF(2,R5,S,IHMSF) + CALL sla_DR2AF(1,D5,S,IDMSF) + WRITE (6, + : '(1X,I2.2,2I3.2,''.'',I2.2,2X,A,I2.2,2I3.2,''.'',I1)') + : IHMSF,S,IDMSF + BAD = .FALSE. + END IF + END IF + IF (BAD) WRITE (6,'(1X,''?'')') + END IF + END DO + + END +</PRE> +In this example, SLALIB not only provides the complicated FK4 to +FK5 transformation but also +simplifies the tedious and error-prone tasks +of decoding and formatting angles +expressed as hours, minutes <I>etc</I>. The +example incorporates range checking, and avoids the +notorious ``minus zero'' problem (an often-perpetrated bug where +declinations between <IMG WIDTH="18" HEIGHT="14" ALIGN="BOTTOM" BORDER="0" + SRC="img1.gif" + ALT="$0^{\circ}$"> and <IMG WIDTH="30" HEIGHT="27" ALIGN="MIDDLE" BORDER="0" + SRC="img2.gif" + ALT="$-1^{\circ}$"> lose their minus +sign). +With a little extra elaboration and a few more calls to SLALIB, +defaulting can be provided (enabling unused fields to +be replaced with commas to avoid retyping), proper motions +can be handled, different epochs can be specified, and +so on. See the program COCO (SUN/56) for further ideas. +<P> +<BR> <HR> +<A NAME="tex2html285" HREF="node5.html"> +<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next_motif.gif"></A> +<A NAME="tex2html283" HREF="node2.html"> +<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up_motif.gif"></A> +<A NAME="tex2html277" HREF="node3.html"> +<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="previous_motif.gif"></A> <A HREF="sun67.html#stardoccontents"><IMG ALIGN="BOTTOM" BORDER="0" + SRC="contents_motif.gif"></A> +<BR> +<B> Next:</B> <A NAME="tex2html286" HREF="node5.html">Scope</A> +<BR> +<B>Up:</B> <A NAME="tex2html284" HREF="node2.html">INTRODUCTION</A> +<BR> +<B> Previous:</B> <A NAME="tex2html278" HREF="node3.html">Purpose</A> +<BR> <HR> <P> +<P><!--End of Navigation Panel--> +<ADDRESS> +<I>SLALIB --- Positional Astronomy Library<BR>Starlink User Note 67<BR>P. T. Wallace<BR>12 October 1999<BR>E-mail:ptw@star.rl.ac.uk</I> +</ADDRESS> +</BODY> +</HTML> |