Stereographic is "always" most realistic, because it is a true projection around the center of the image, viewed from a point on the opposite side of the sphere. This means that great circles passing through the image center are straight lines at the correct angle, so you can use it at wide angle to trace meteor or LEO satellite tracks across the sky. BUT, Stereographic in SkyMap is sensitive to the F7/F7 setting AltAz/Equatorial - in AltAz THOSE track values are correct, but the stars only at the selected map time! Polar is "true" near the poles. Rectangular is good near the equator, and may help if you have a polar mount scope and know the directions. Stereographic then is true to your view in hand-held prismatic binoculars (and naked eye) /Björn ----- Original Message ----- From: <chiayk1@singnet.com.sg> To: <seesat-l@satobs.org> Sent: Monday, August 04, 2008 3:51 AM Subject: Questions on Skymap Projection vs UNID matching Hi folks: In Rob's Skymap pro: Which map projection is 'closer' to the real view? Rectangular or Steoroegrahy. I was trying to ID a flasher last night and found that changing the map proj view had a big effect between matching the trajectory versus background stars ( distance from it). [This sat is suppose to be half the distance between two recognised stars but only one projection show it properly w.r.t stars.] Thanks rgds ykchia -------------------------------------------------------------------- mail2web.com - What can On Demand Business Solutions do for you? http://link.mail2web.com/Business/SharePoint ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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