We give one point per unit for a pertinent contribution to the discussion.
We compile discussion points twice per term: Once in preparing to file midterm grades, and once at the end of the course (after the deadline for all units but before the final exam is offered for most on-campus students). In between these times, we read the discussion and sometimes contribute a comment or an answer. If we spot an answer that is clearly given in good faith but is wrong, we will either post a correction or email you about it.
A pertinent comment contains a question about the material, an answer to a previously posted question*, some added information* about the material of the unit, or a link** to an external site other students may find interesting or helpful in learning the material of the unit.
*Your answer or added information needs to be substantially correct to receive full credit.
** When you provide a link, please do assure yourself that it is a reliable link.
1. Check who is providing the information for the site. If it is provided by NASA, a major astronomical observatory (such as the US Naval Observatory), or a university faculty member with expertise in astronomy you may assume it is authoritative information and cite it (even though some of these sources occasionally err). Other reasonable sources include magazines such as Science, Nature, Scientific American, Astronomy, or Sky and Telescope. Not all popular-science magazines are equally careful, though! Another place to look is organizations such as the American Association of Variable Star Observers.
2. Check the information on the site against other sources – reliable textbooks, authoritative sites, material provided in the course. If they agree where they concern the same material, this is evidence in favor of the site (but not proof that it is reliable). If they disagree – email your instructor and we will take a look! If the error is in our materials, finding it gains you a bonus point.
3. Sites that you find using links from a reliable site are more often reliable than sites you find from a random search. Here is a list of some reliable and useful sites.