University of Hong Kong

Development Web Pages Using HTML and JavaScript

Case 10

Extracted from

Creating Web Pages with HTML and XML

By Patrick Carey, Mary Kemper

Thomson Course Technology

Page 5.43

SkyWeb Astronomy

Dr. Andrew Weiss of Central Ohio University maintains an astronomy page for his students called SkyWeb. In his Web site he discusses many aspects of astronomy and observing. One of the pages he wants you help with involves the Messier catalog, a list of deep sky objects of particular interest to astronomers and amateur observers.

Dr. Weiss wants his page to contain a slide show of various Messier objects, displaying both a photo of the object and a text box describing the object's history and features. He wants his users to be able to click a forward or backward button to move through the slide show. The rest of the Web page remains unchanged as users view the presentation.

To create a presentation like this, you'll need to insert one floating frame inside of another. Dr. Weiss has created the text you need for the Web site. Your job is to create the fames needed to complete the Web page.

Incomplete HTML Source for case10.htm:

<html>

<head>

<title>The Messier Objects</title>

</head>

<center<img src="skyweb.jpg" alt="SkyWeb"</center>

<h1<font face="monospace">The Messier Objects</font</h1>

<p<b>Messier objects</b> are stellar objects, classified by astronomer <b>Charles

Messier</b> in the 18th century, ranging from distant galaxies to star clusters to

stellar nebula. The catalog was a major milestone in the history of astronomy, as it

was the first comprehensive list of deep sky objects. Ironically, Charles Messier

wasn't all that interested in the objects in his list. He made the catalog in order

to <i>avoid</i> mistaking those objects for comets, which were his true passion.</p>

<p>Messier objects are identified by <b>Messier Numbers</b>. The first object in

Messier's catalog, the Crab Nebula, is labelled <b>M1</b>. The last object, <b>M110</b> is a satellite galaxy located in the constellation Andromeda. There is no systematic ordering in the Messier Catalog. Messier entered objects into the list as he found them. Sometimes he made mistakes and once he entered the same stellar object twice. The catalog has undergone some slight revisions since Messier's time, correcting the mistakes in the original.</p>

<p>

<?????? src="m01.htm" align="?????" width="460" height="240" marginwidth="0"

marginheight="0" hspace="5" frameborder="no">

</??????

One of the great pursuits for amateur astronomers is to do a <b>Messier Marathon</b>,

trying to view all of the objects in Messier's catalog in one night. Unfortunately,

if you want to see all of them, you have to start looking right after sunset and continue

until just before sunrise  hence the term, "marathon." March is the only month

in the year in which an astronomer can run the complete marathon.</p>

<p>Use the buttons to view some of the more popular objects in Messier's catalog.</p>

<hr>

<tr>

<b>

</b>

</font>

</td>

</tr>

</table>

</body>

</html>

Incomplete HTML Source for m01.htm:

<html>

<head>

<title>M1: The Crab Nebula</title>

</head>

<tr>

<th>

<font face="monospace" size="5">M1: The Crab Nebula</font>

</th>

</tr>

</table>

??????

src="m01desc.htm" width="250" height="164">

/?????

<tr>

<? ????="m57.htm"<img src="lbutton.jpg" border="0" alt="Previous" vspace="5"</?

</th>

<? href="m13.htm"<img src="rbutton.jpg" border="0" alt="Next" vspace="5"</?

</th>

</tr>

</table>

</body>

</html>
HTML Source for m01desc.htm:

<html>

<head>

<title>M1: The Crab Nebula</title>

</head>

<p>M1, known as the Crab Nebula, is one of the most famous supernova

remnants in the night sky. The supernova was first noted on July 4, 1054 by

Chinese astronomers. At its height, the supernova was about 4 times

brighter than Venus and could be seen during the day for a period of more than

three weeks.</p>

<p>The remnant of the this supernova was discovered in 1731 by the British

astronomer, John Bevis. Messier himself found it in 1758 while looking for

Halley's comet. He soon realized it was no comet and the Crab Nebula became

the first entry in Messier's famous catalog of celestial objects.</p>

</font>

</body>

</html

Incomplete HTML Source for m57.htm:

<html>

<head>

<title>M57: The Ring Nebula</title>

</head>

<tr>

<th>

<font face="monospace" size="5">M57: The Ring Nebula</font>

</th>

</tr>

</table>

?????? src="m57desc.htm" width="250" height="164">

</??????

<tr>

</th>

</th>

</tr>

</table>

</body>

</html>

HTML Source for m57desc.htm:

<html>

<head>

<title>M57: The Ring Nebula</title>

</head>

<p>M57, the Ring Nebula, is one of the most beautiful objects

in the Northern sky. It was discovered by Antoine Darquier de Pellepoix

in 1779. M57 is believed to be a planetary nebula, similar in

structure to M27.</p>

<p>The Ring Nebula contains a central star, discovered by the German

astronomer, F. von Hahn, in 1800. Observing the central star is one

of the great challenges of amatuer astronomy. The star itself is a

planet-sized white dwarf. The Ring Nebula was probably formed when

this central star exploded long ago.</p>

</font>

</body>

</html>

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