2. CELESTIAL NAVIGATION: HOW MUCH DO YOU ALREADY KNOW? PRESENTER: JEFF GOLDSTEIN, BBAA SECRETARY https://en.wikipedia.org/wiki/Sextant#/media/File:Using_sextant_swing.gif

3. HOW DO WE READ A SEXTANT?

4. CELESTIAL NAVIGATION TERMS -ALTITUDE (H S  H A  H O ) IC & DIP REFRACTION/PARALLAX -AZIMUTH (Z N ) -GREAT CIRCLES (MAKES CALCULATIONS EASY FOR LAN SHOOT) -LOCAL APPARENT NOON (LAN) -EQUATION OF TIME (ANALEMMA) (SLOW UNTIL APRIL 15, THEN FAST )  -MERIDIAN (WHEN THE SUN CROSSES OUR MERIDIAN, WHAT DIRECTION WILL WE BE LOOKING?) -INTERPOLATION (MATHEMATICAL CALCULATION TO APPROXIMATE PERCENTAGE BETWEEN TWO NUMBERS) -NAUTICAL AND AIR ALMANAC (ADVANTAGES?) -DECLINATION (OF A BODY) MEASURED FROM? -GREENWICH HOUR ANGLE (GHA MEASURED ONLY IN WHICH DIRECTION? ) -LOCAL HOUR ANGLE (LHA RELATES GREENWICH, YOU, AND THE OBSERVED BODY ) -SIDEREAL HOUR ANGLE ( SHA FOR STARS; RELATED TO RIGHT ASCENSION ) -RIGHT ASCENSION (NOT USED IN CELESTIAL NAVIGATION, BUT USED IN ASTRONOMY)  -ATMOSPHERIC REFRACTION OF ALL BODIES -PARALLAX (HP AND PA) OF THE SUN, MOON, OR MARS -SEMI-DIAMETER (SD) OF SUN AND MOON; WHY IS THIS IMPORTANT?

5. TONIGHT’S GOAL: LOCAL APPARENT NOON SIGHT DONE ON APRIL 3, 2016 (RELATIVELY) SIMPLE TO DETERMINE LAT. & LONG. FIX https://www.youtube.com/watch?v=HytZfJ0GR8k&list=PLlEANaBy6Br0C0LmYQgx8WhsIJ2jwGLI_ (Start the above video at 3:30 for his quick version of Local Apparent Noon Sight) Note also that he only uses his line of latitude. We will go further to refine our longitude, too. Here’s another YouTube on Celestial Lighthouses that is interesting and explains Celestial Navigation Terms https://www.youtube.com/watch?v=wICHhoLaims&index=39&list=PLlEANaBy6Br0C0LmYQgx8WhsIJ2jwGLI_

6. Today, what is the approximate declination of the sun? (think of the season and when summer begins) Don’t we need the exact declination for the sighting? We will interpolate exact declination between two from the table, later.

7. THE SUN’S GEOGRAPHIC POSITION : Sun’s Geographic Position & Zenith Distance = (90 – H o )* (where H o is the sun’s highest altitude found) But when will that be? We can predict it (Nautical Almanac)  add 4 minutes, since we’re at 76° W. Therefore, at approximately 17:07 UTC (12:07 + 5 hours Eastern Time Zone) ( or 13:07 EDT ) Also, what True Direction would we expect it? * Proof of (90 – H o ) on the next slide.

10. ARTIFICIAL HORIZON (ALWAYS GIVES 2X THE ACTUAL ALTITUDE)

12. Nautical Almanac

13. Air Almanac

14. FOR LATITUDE CALCULATIONS Latitude = (90 – H o ) ± Sun’s Declination N/S add for N, subtract for S Latitude = Sun’s Z.P. + Sun’s Declination N now above the equator

15. FOR LATITUDE CALCULATIONS Latitude = (90 – H o ) ± Sun’s Declination N/S add for N, subtract for S Latitude = Sun’s Z.P. + Sun’s Declination N now above the equator Latitude = (89° 60’ – H o ) + 5° 39.87’ Latitude = 31 ° 4.3’ + 5° 39.87’ Latitude = 36° 44.17’ Actual Lat: 36° 45.168’ (error: 0.998 miles)

16. FOR LONGITUDE CALCULATIONS We must have an accurate chronometer set to WWV, CHU Canada, or USNO (time hack). WWV on short wave radio frequencies: 5, 10, 15, 20, and 25 MHz. Recording: https://ia902309.us.archive.org/20/items/WWV15MHz/WWV-15MHz.MP3 (i.d. at 0 + 38)https://ia902309.us.archive.org/20/items/WWV15MHz/WWV-15MHz.MP3 USNO online: http://tycho.usno.navy.mil/simpletime.html or cell phone dial: (202) 762-1401http://tycho.usno.navy.mil/simpletime.html CHU on short wave radio frequencies: 3.330, 7.835, 14.670 MHz

17. LONGITUDE CALCULATIONS (CONT’D) Average the matching pairs of the same altitude (shot before and after LAN) 17 : 12 :: 05 = 17.2013889 hours + 17 : 2 :: 25 = 17.0402778 hours 34 : 14 :: 30 = 34.2416667 hours ÷ 2 (for an average) 17 : 7 :: 15 = 17.1208333 hours - 12 : 0 :: 00 5 : 7 :: 15 = the GHA - 3 :: 08 (from the Nautical Almanac) 5 : 4 :: 07 = the time corrected GHA 5(15) + 4(15/60) + 7(15/3600) =76.02916667 degrees 75 + 1 + 0.0291667=76° 1.75’ (error of 1.287 nm)

18. RESOURCES “Davis Sextant User’s Guide: Mk 15 & Mk 25”, Hayward, CA. online www.davisnet.com.www.davisnet.com Kreitlein, CDR Chris, USN Retired, “Simple Celestial: Navigation by the Heavens Made Easy”, 3 rd ed., Globus Horizon, Pensacola, Fla, 2013. “Nautical Almanac”, Commercial Edition, United Kingdom Hydrographic Office, 2014. “Nautical Almanac” 2016 Edition (online) http://www.thenauticalalmanac.com/http://www.thenauticalalmanac.com/ Sailing Vessel Navigator, Chris “Going Further in Celestial Navigation: A Day with the Sun” https://www.youtube.com/watch?v=HytZfJ0GR8k&list=PLlEANaBy6Br0C0LmYQgx8WhsIJ2jwGLI_ https://www.youtube.com/watch?v=HytZfJ0GR8k&list=PLlEANaBy6Br0C0LmYQgx8WhsIJ2jwGLI_ “Sextant”, Wikipedia (online) https://en.wikipedia.org/wiki/Sextanthttps://en.wikipedia.org/wiki/Sextant

19. QUESTIONS ? & ANSWERS