Copyright Statement

All of the written material and some of the graphics (static images and animations) on these pages are copyrighted by Richard W. Pogge unless otherwise noted, and may not be reproduced without written permission.

Educational or non-profit organizations wishing to reproduce or provide links to any part of these pages must contact Richard Pogge ( in writing. Please see the Usage Guidelines below for specific information.

Usage Guidelines

These web pages are intended primarily for use by Ohio State University students enrolled in Astronomy 350 during Autumn Quarter 1998. To facilitate using these pages as part of their course work, students formally enrolled in this section are granted permission to make single copies of the online notes in unaltered form for exclusive personal use only, provided that all copyright notices and citations of images and text sources remain intact. "Personal Use", however, does not extend to additional reproduction, alteration, distribution, or resale of these notes in any form to anybody.

All other interested persons who are not enrolled in this course at The Ohio State University are welcome to browse these pages, provided that they observe the following usage restrictions:

  1. Educators, educational organizations, or registered non-profit organizations may link to these pages from their websites, provided they contact Richard Pogge ( so that I have a record of who is using this material outside of The Ohio State University.
  2. You may not reproduce, distribute, or resell any of the materials on these pages in any form, nor may you charge others to access these pages. In particular, you are specifically prohibited from including any of the written or image material, in whole or in part, in course note or lecture note packages compiled with the intention of reselling them to students enrolled in this or related courses at this or other educational institutions.
  3. Citations of factual material in these pages should be to the original sources. Please contact the author of these pages for information on the correct citation of particular materials.

A Brief Note About Copyrights

The precise relationship between current Copyright Laws and publically accessible electronic documents on a world-wide Internet is presently a subject of considerable discussion and debate both inside and outside the courts. Copyrights are an essential protection for teachers and students alike, as they play a fundamental role in helping to preserve the integrity of our intellectual activities (writing, images, etc.) by protecting our creative works from commercial exploitation by others. I take the issue of copyrights very seriously in the production of these web pages.

If you notice any inappropriately used or incorrectly cited text or images, please contact me so that I can either seek the proper use permissions or delete them from these pages (providing substitutions where possible).

Text Sources

I have made a good faith effort to be very careful about not including copyrighted text (other than my own) in these pages, except where I have sought specific permission from the original authors. I would appreciate help correcting any erroneous citations to primary sources you might spot in these pages.


Images are essential to teaching astronomy, and present a range of copyright problems in the context of the Internet. Since copyright law with regards to graphics is still being developed, I have little guidance except common sense. As such, I use primarily public domain images on these pages, taking care to correctly cite the original sources, and have sought permission for other images (e.g., I have an agreement with the Anglo-Australian Observatory for use of some of their copyrighted images on these pages).

Some of the images and graphics displayed during lectures are copyrighted material not available in the public domain. While use of these images in lecture is permitted under the heading of "Fair Use", posting these same images to the Web is another matter altogether. I am seeking permission from the original sources to post some of the graphics on these pages, but not all persons have granted permission. For example, the publishers of the textbook allow me to scan a very limited number of graphics from the book for display in lecture (taking the place of their plastic overheads), but they have not granted permission to post them to the web. This can be somewhat inconvenient for the student, as a number of the images and graphics used in lecture are not available online and so the notes are sometimes incomplete in that sense, but this is unavoidable.

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Updated: 1998 August 30 [rwp]

Copyright 1996, 1998 Richard W. Pogge, All Rights Reserved.