--- Richard Tenney <retenney@yahoo.com> wrote:

Patrick, would you or Kurt mind posting a link to a simple lunar map to indicate again where we should be watching for impact? Recommendations as to magnification?

For online photos, the Full Moon Atlas - Plate G1 - has a regional views with rollovers for crater names and features. http://www.lunarrepublic.com/atlas/sections/g1.shtml You are looking for Crater Clausis, which is north of the big crater, Schickard, near the middle of the Full Atlas image. Lacus Excellentiae also has a rollover.

From a close-up view, let's pull back to larger FOVs:

LPOD 3/16/2006 - Close up of impact zones near C. Clausius http://www.lpod.org/?m=20060316 ESA closeup maps for the three potential impact times http://www.esa.int/esaCP/SEMRR46LARE_index_1.html http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=39841 http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=39863 LPOD File 10/43 - Lacus Excellentiae - Close http://lpod.org/coppermine/displayimage.php?pos=-602 LPOD File 10/43 - Lacus Excellentiae - Farther out http://lpod.org/coppermine/displayimage.php?pos=-461 Area photos - Full Moon Atlas - Plate G1, above http://www.lunarrepublic.com/atlas/sections/g1.shtml Consolidated Lunar Atlas plate GIV http://www.lpi.usra.edu/resources/cla/info/giv/ From LPI Lunar Atlases Online http://www.lpi.usra.edu/resources/lunar_atlases/ USGS Map a Planet http://pdsmaps.wr.usgs.gov/PDS/public/explorer/html/moonlvls.htm To get in the general vicinity of C. Clausius, I would use C. Hanzel, a prominent crater that will be near the terminator, as your visual yardstick. Go two lengths of Hainzel in west selenographic longitude (east in the eyepiece) and one Hanzel length in north selenographic latitude. As to magnifications, basically all the impact points fall into an 8 x 6 selenographic deg rectangle. Because the impact will be on the dark limb side of the Moon, pointing your scope will be a challenge. If you cannot find Schickard in the dark limb, I'm thinking the best thing to do is to use a quarter Moon TFOV - which would be about 8 arcmins or 480 arcseconds for the Moon's distance of about 378,000 kilometers at that time. In general, for visual observing apply Knisely's basic rules for magnification of planetary detail - between 30 and 42 power _per inch of aperture_. You will probably only be able to use the lower end of the range due to atmospheric turbulence. Balance magnification against the difficulty of locating a position on the Moon's dark limb. At the stated selenographic lat and long, 60 arcsecs is about 140 kilometers in diameter. Nowhere at the ESA site do they specifically say what the visual magnitude of the impact will be. At best the ESA suggests that "Even if the impact at 2 kms-1 is of modest energy, the plume might be observable if it reaches sunlight, with an amateur telescope or binoculars." The ESA does say for the infrared range that the absolute magnitude of the impact will be between 11-16 magnitudes. See - http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=39839 There are three likely impact times, only one of which is visible from Utah at night. The time and point of impact is not fixed due to uncertainities concerning the altitude of the lunar terrain. There are three potential impact times with the Moon low in the sky for Northern hemisphere observers: http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=39878 Nominal -1 3 September 2006 00:36 UT 43.5° W 36.4° S Nominal 3 September 2006 05:41 UT 46.3° W 36.4° S Nominal +1 3 September 2006 10:46 UT 49.0° W 36.3° S Note the following qualifier on the time and place of impact on the ESA website, listed above: "During SMART-1's last orbits, the perilune altitude naturally decreases by about one kilometre per orbit. This means that, if encountering unknown peaks in the terrain between one and two kilometres high, SMART-1 may hit ground one orbit or even two orbits earlier than the nominal impact orbit." "The best lunar topographic maps currently available are based on data from the US Clementine mission in 1994. The laser altimeter experiment (LIDAR) on board provided the spacecraft altitude over a grid with roughly 1 kilometre intervals. The values in between have been interpolated by the SMART-1 experts, assuming there are no peaks." Hope that helps. - Kurt P.S. Goes to show how much we do not know about our closest neighbor. There may be a "little" one or two _kilometer_ tall mountain in the way. We are just not sure. __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

--- Patrick Wiggins <paw@wirelessbeehive.com> wrote:

Impact is predicted to occur in the shadowed area. FWIW, I'll be really surprised if anyone sees the impact through the eyepiece.

Richard, I feel Patrick is calling it right. The tell is the ESA's note that it might be visual if the plume reaches up from the darkness and is illumniated by the sunlight. I haven't worked the trig out based on the negative sun angle, but I'd suspect that is a pretty big vertical reach in kilometers. Sounds like photographic is the way to go. In short, probably shouldn't get worked up about it, but it is worth a peak. - Kurt __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com