eric
/
MaineEdu


			
							123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172
							<HTML lang="zh">
	<HEAD>
<meta http-equiv="Content-Type" content="text/html;charset=utf-8">
<meta name="MSSmartTagsPreventParsing" content="TRUE">
		<META Name= "description" Content = "Zhang Heng 78-139 and the ecliptic - brief introduction to Chinese Astronomy and the Beijing Ancient Observatory.">
		<META NAME="distribution" content="Global">
		<META NAME="rating" content="Safe For Kids">
		<META NAME="copyright" content="Marilyn Shea">
		<meta name="Author" content="Marilyn Shea">
		<META NAME="classification" content="Education">
		<META Name = "keywords" Content = "China, Zhang Heng, Chinese, astronomy, Tian Wen Tai, ancient observatory, Marilyn Shea">
		<TITLE>Zhang Heng  张衡 - Ecliptic - 黄道 -Chinese Astronomy - 中国天文学</TITLE>
		

	</HEAD>

<BODY bgcolor=#333333 text=#FEFAFA link=#FFFFFF vlink=#FFFFFF alink=#FF0000>

<CENTER>
<TABLE border="0" cellpadding="0" cellspacing="2" width="200">
<TR>
	<TD width="80" align="center"><A href="0012ZhangHeng6539w.html"><IMG src="../tianimage/previous.gif" height="30" width="30" border="0" title="Previous"></A></TD>
	<TD width="80" align="center"><A href="../index.html#11"><IMG src="../tianimage/home.gif" height="30" width="30" border="0" title="Home"></A></TD>
	<TD width="80" align="center"><A href="0013steelyardclock6629w.html"><IMG src="../tianimage/next.gif" height="30" width="30" border="0" title="Next"></A></TD>
</TR>
</TABLE>
</CENTER>


<center>
			<table border="8" cellspacing="2" cellpadding="4" bgcolor="black">
				<tr>
					<td bgcolor="black"><A href="0013steelyardclock6629w.html"><IMG src="../tianimage/0011H_6680w.jpg" height="600" width="840" border=0 title="Zhang Heng's measure of the ecliptic"></a></td>

				</tr>
			</table>
		</center>
		<br>
		<div align="center">
			<h1><font size="-1" color="white" face="Verdana, Arial, Helvetica, sans-serif">The Ecliptic - 黄道<br>
				</font></h1>
			<div align="center">
				<table width="60%" border="0" cellspacing="2" cellpadding="0" align="center">
					<tr>
						<td><font size="-1" face="Verdana, Arial, Helvetica, sans-serif">Zhang Heng, within his theory of the cosmos, said that earth is tilted so that the north is higher. He found that it was 26°5' which is just 3° off the modern measurement of 23°27'. The ecliptic (</font><font size="-1" color="white" face="Verdana, Arial, Helvetica, sans-serif">黄道 huángdào</font><font size="-1" face="Verdana, Arial, Helvetica, sans-serif">) is the apparent path that the sun follows over the earth. It occurs because the earth is tilted in relation to its orbit around the sun, so the earth's equator, as determined by its own revolution, is at an angle to the sun.   In the illustration above, the traditional map orientation in China is used; north is on the right.  </font>
							<p><font size="-1" face="Verdana, Arial, Helvetica, sans-serif">He also recorded the angular diameter of both the sun and the moon which is 1/736 of the celestial sphere, or rather 29°21″, a difference of 2° from the average value of 31°5″. </font></p>
							<p><font size="-1" face="Verdana, Arial, Helvetica, sans-serif">He improved on the precision of the celestial maps of his day, mapping about 2,500 stars, 124 constellations, and noting the names of the 320 brightest stars. He noted that there were an additional 11,500 small stars only seen by sailors. He placed horizontal and vertical lines on his charts based on the angle of arc, in other words, he invented longitude and latitude measures. The Chinese likened it to throwing a net over the world.</font></p>
							<p><font size="-1" face="Verdana, Arial, Helvetica, sans-serif">Below, Zhang Heng is shown with the reflection of the instruments on top of the sun shadow hall at the Ancient Observatory in Beijing (古观象台).</font></p>
						</td>
					</tr>
				</table>
			</div>
		</div>
		<CENTER>
			<br>
			<table width="64" border="8" cellspacing="2" cellpadding="6" bgcolor="black">
				<tr>
					<td><a href="0013steelyardclock6629w.html"><img src="../tianimage/ZhangHeng9373w.jpg" title="Zhang Heng" width="442" height="600" border="0"></a></td>
				</tr>
			</table>
			<br>
		</CENTER>
		<br>
		<br>
<br><HR><P><font size="-1" face="Verdana, Arial, Helvetica, sans-serif">http://hua.umf.maine.edu/China/beijing2.html<BR>Last
update:  May 2007<BR>&copy; Marilyn Shea, 2007 </FONT></P><HR>
<br>
</BODY>


</HTML>