|Alt-Az coordinates Part 2 for35s|
Message #1 Posted by Howard Lazerson on 20 Aug 2007, 10:46 p.m.
Thanks Gerson for making pgm readable! This pgm is designed to convert right ascenion & declination of any celestial body into simple altitude and azimuth. You therefor need to make/copy /draw a 360degree az circle on the mount base and a 0 to 90 degree scale for alt, 0 being level, 90 pointing straight up. Marking every 10 degrees is sufficient since its easy to interpolate. The # 6.619 is a constant and changes yearly, for2008 = 6.603, for 2009 =6.654. U is GMT for Calif, 10PM this August =5.0 , when daylight sav ends it is 6.0, use decimal minutes, 9:30 PM= 4.50 GMT. Latitude & longitude of your site are decimal degrees. Day number - add date to this # so for August 20= 212 + 20 = 232. Jan=0,Feb=31, March = 59, April=90, 120, 151,181, 212, 243, 273, 304, and 334 for Dec. Right & declination are also input in decimal degrees. To get accurate results, the scope must be LEVEL- I mounted a bullseye level on my portable scope which works well. Sight Polaris [north star] and set Az to read 0 degrees, use a red light preserves nite vision ], look up RA & Dec of object, run pgm to get alt/az and slew scope to these coordinates. Use a widefield-low power eyepiece initially since there is a 1 to 3 degree offset in position-slowly slewing from the calculated position will locate object quickly. One really appreciates this pgm with objects 0ver 50 degrees high-no more on your knees squinting up while your back complains. Howard