Nevertheless, many of these materials are copyrighted, subject to royalties, or usage restrictions. This is normally, but possibly not always, indicated in the relevant pages (e.g., near the materials) to our best knowledge, either by an explicit copyright statement or a source acknowledgement. In any case, it is the responsibility of the user to observe all third party rights of the materials in our pages (especially in case of any for-profit usage); in particular, check with any source, indicated in our pages or not, if you consider such usage. Please contact me in case you have any questions.

• Summary of some image sources, with indication of usage restrictions

The SEDS Messier Catalog database as a whole is the collective intellectual property of its creators, SEDS, and in its present form, of its maintainer and his co-author. Materials not restricted by above regulations may be freely used for non-profit, educational purpose, if the SEDS Messier Catalog online database is properly acknowledged as source, under the following conditions:

• No further restriction of their distribution or use is implied.
• It is not implied that SEDS or one of the authors endorses a product, service, activity etc which was not explicitely stated by us, or any other misleading way.
• No false rights are claimed, in particular of authorship, ownership, copyright, etc.

We particularly appreciate (and encourage) full or partial official mirroring of our stuff, please look at our mirrors webpage.

[The following added February 15-18, 2005:]
In addition, any kind of usage, commercial or non-commercial, is subject to the following non-negociatable regulations:

• No kind of usage is granted aimed to hinder, damage, censor, or otherwise take influence, or attempt any of these, on the continuous maintainance, updating, debugging, correcting or developing of the contents of these services.
• In case of any cooperative ventures, the user of our materials agrees that we are free to use the knowledge acquired during these ventures for updating, debugging, correcting or developing of the contents of these services. The user agrees not to attempt to inhibit or delay any such activity by us.
• Permissions of any kind can only be granted on non-exclusive basis; there is no way to obtain any form of exclusive usage rights from us.

Important Notice: Recently, a small but unfortunately increasing number of sites have started to claim false copyrights on stuff originating or obtained from us. We strongly deprecate this practise, state that it is unlawful to claim inappropriate rights on stuff originating from our services (see our usage regulations above), and particularly emphasize that this might cause third-party royalty holders, or at some time even ourselves, to bring serious problems to those falsely claiming any ownership rights on their (the owners') stuff. Concerned parties are requested to remove any false claims of rights.

July 12, 2001
Hartmut Frommert, Maintainer of the Messier pages at SEDS

Sometimes we are asked how to acknowledge this website. Basically you are free to create your own piece of text to do this, but here is a suitable example (replace the second year number by current year, or by "to current"):

• The SEDS Messier Catalog Webpages. By Hartmut Frommert, Christine Kronberg, Guy McArthur, and Mark Elowitz. SEDS, University of Arizona Chapter, Tucson, Arizona, 1994-2006. http://messier.seds.org/

• http://messier.seds.org/

For any subpages, acknowledgements may be created in analogous manner, e.g.:

• For the M1 page similar to:
  • Messier Object 1. By Hartmut Frommert, Christine Kronberg, and Guy McArthur. SEDS, University of Arizona Chapter, Tucson, Arizona, 1994-2006. http://messier.seds.org/m/m001.html
  • http://messier.seds.org/m/m001.html
• For our Milky Way page like:
  • The Milky Way Galaxy. By Hartmut Frommert, Christine Kronberg, and Guy McArthur. SEDS, University of Arizona Chapter, Tucson, Arizona, 1994-2006. http://messier.seds.org/more/mw.html
  • http://messier.seds.org/more/mw.html

Last Modification: August 19, 2006