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Navigation. Navigation. Chapter 6 Sight Planning. Learning Objectives. Set up star finder for any location & time Plot planets, sun & moon on star finder Use “ Sight Planner “ in Celestial Tools Select suitable bodies for fixes Identify unknown celestial body. Navigation.
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Navigation Chapter 6 Sight Planning
Learning Objectives • Set up star finder for any location & time • Plot planets, sun & moon on star finder • Use “Sight Planner “ in Celestial Tools • Select suitable bodies for fixes • Identify unknown celestial body
Navigation How many sights do you need for the sight folder?
Sight Considerations Stars & Planet Sights: • Usable observation period - 15 to 45 min • Morning: maybe an hour before sunrise • Evening: brightest until no longer see horizon Moon Sights: • Daytime: 2-body fix with sun • Twilight: 2/3-body fix with sun/star/planet
Sight Considerations Twilight Sights: • Predict altitudes & Zn • Morning - bodies to the west first • Brightest bodies first • Take sights on any bright body Daylight Sights: • Sun near MT, bearing changes rapidly • Moon/Venus occasionally visible • Sun-Moon after/before 1st & last quarter
Sight Considerations Ideal LOP separations for fix: • 90° for 2-body, minimum 45° • 120° for 3-body, minimum 30° MPP Venus 0850 Sun 0830 Sun 0830 Moon 0845 Moon 0845
Sight Planning • Internet & App’s • Computers – Celestial Tools • Star Finder • Nautical Almanac
Star Finder • Manual Tool – backup • For any given time & location, determine: • Approximate altitude & Zn of bodies • Navigational stars, sun, moon & navigational planets
Star Finder • Star Base (white disc) • Red Template • Blue Template
Star Finder • Star Base • Celestial Sphere • Northern Hemisphere • Southern Hemisphere • Poles at center of disc • Celestial Equator 4” circle • Shows Navigational Stars • Relative magnitude • LHA scale, Aries at 0° • Right Ascension (RA) RA: 24° SHA: 336° Total: 360°
Star Finder • Red Template • Overlay • Plot planets, sun & moon • North/South side • Declination circles • Meridian angle scale • Plotting slot
Star Finder • Blue Template • Overlay • 10° intervals, 5° - 85° • Nearest your DR • North/South side • Blue grid visible area • (mount & align LHA 310°) • Center cross is zenith • Outer ring is horizon • Radial lines are azimuth • Curved lines are altitude
Star Finder Exercise • Blue Template • LATITUDE 45°N overlay • Mount on Star Base • Align arrow with LHA 259° • 7 - 1st Mag stars visible? Antares hs 18 Zn 192 Spica hs 14 Zn 240 Arcturus hs 45 Zn 252 Capella hs 2 Zn 179 Deneb hs 55 Zn 70 Vega hs 75 Zn 115 Altair hs 42 Zn 125 What about the sun, moon, Venus, Mars, Jupiter, & Saturn? What are their hs & Zn?
Star Finder Exercise 4/14 45 25.6N 45.4 92 30.0W 6 Morning CT 45.4 50N 0435 45.0 45N 0446 0.4 5 -11 0.18 0446 0446 92.5 90.0 0456 10 0446 2.5 +5 0956 6. Enter the GHA for Aries. 1. Determined LMT for DR Lat. 2. Adjust LMT for DR Lo. 7. Determined RA for bodies. 4. Determine LHA of Aries. 5. Look up GHA, SHA and Dec. 3. Compute UT. 314.9 337 42.1 9 269.7 14 02.3 56 14 02.3 333.3 351 44.4 336.6 -92 30.0 287.2 259 14.4 142.2 259 36.8 9.5N 314 56.3 351.7 269 42.0 82.0 19.9N 333 17.0 26.7 10.1N 23.4 9.4N 336 34.0 72.8 22.1N 287 09.7 142 14.4 217.8 12.0S
Star Finder Exercise • Mount Red Template on Star Base • Align arrow with RA for Sun • Using slot on template, place dot at 10° N Dec and label with symbol (use pencil) • Repeat for other bodies Body Sun Moon Venus Mars Jupiter Saturn Dec 10° N 20° N 10° N 09° N 22° N 12° S RA 37° 82° 27° 23° 73° 218°
Star Finder Exercise • Replace with LATITUDE 45°N overlay • Align arrow with LHA 259° • What are the hs & Zn for these bodies? • Saturn: hs 22° Zn 223° ħ
Take bearing of body Set star finder for time of sight Altitude & approx. bearing Bodies on star base located in vicinity Reduce sight If correct, intercept close to DR If star is not very bright, may not be nav. star List of stars, pg 268 - 273 NA Estimate SHA & Dec; look it up in star list Star Identification Hudson Wi Mar 24, 2013 10:05 PM 18
Navigation Next week bring your calculator or abacus CHAPTER 3 LHA, Dec, Ho
Sight Planning The End