Sight Planning Homework Solutions Global Navigation Chapter 6

Sight Planning Homework Solutions Global Navigation Chapter 6 1

Objectives n n Internet resources to identify & locate celestial bodies. Use an electronic sight planning tool, Sight Planner in Celestial Tools. Set up a USPS star finder for any location & time. 2

Objectives (continued) Select suitable bodies for fixes at twilight or in daytime. n Identify an unknown celestial body listed in NA. n 3

Pratical Exercise 1 Set up the Star Finder for your present location, at any convenient time on the evening of the day you are reading this. List the planets and first-magnitude stars that will be visible with their azimuths and altitudes to help in locating the bodies. Then go outside and find as many of the listed bodies as you can. n 2. Use Celestial Tools to determine the planets and first-magnitude stars that will be visible with their azimuths and 4 altitudes.

Question 3 To plot a body on the star finder, set the red template arrow to the value of: a. LHA Aries. b. GHA Aries. c. Right ascension (RA). d. Declination. n Ref: ¶ 46 5

Question 4 If you rotate the blue template to mimic the passage of time, the arrow will indicate: a. Increasing values of LHA Aries. b. Decreasing values of LHA Aries. c. Increasing values of right ascension. d. Decreasing values of right ascension. Ref: ¶ 40 6

Question 5 Right Ascension of the sun is equal to: a. GHA Aries – GHA sun. b. 180° - SHA sun. c. 180° + SHA sun. d. SHA sun – GHA sun. Ref: ¶ 48 7

Question 6 Set your star finder for the northern hemisphere, with the red template in place. Find the solution to a. Then, using the appropriate blue templates c. What is its altitude at meridian transit at d. What is its altitude at meridian transit at Latitude b. What is its altitude at meridian transit at and appropriate side of the star base, find the Latitude 25°S? 75°S? Latitude 75°N? solutions to b, c, and d. c. Answer : 38° Answer: 42° a. What is the declination of? d. Answer: Body is below the horizon. Solution : Set 25°S blue template on south base Solution 6 b : Calculate RA of Alphecca? d. Solution: Set 75°S blue template on south Answer : 27° (by inspection). at 234° and read altitude. Altitude is 38° RA = 360° - SHA = 360°-126° 16, 7’ = base at 234° and read altitude. Body is below the 233° 43, 3’ (rounded to 234°) horizon. Set 75°N blue template on 234° and read altitude. Altitude is 42°. 8

Question 7 a Use the Excerpts from the Nautical Body GHA RA Dec LHA Magnitude Body 360° -SHA =RA Dec GHA Almanac, Appendix B, for the following Soleil 179° 100° 23°N questions. You are at L 35°N, Lo 62°W. It is Venus 360° 291° 069° 18°N -4, 4 211° ZT 2000 on 30 Moon 22° June. 257° 26°S Mars 360° 234° 126° 20°N +1, 8 152° a. Jupiter For this time, plot the planets on the star base 279° 195° 217° 23’ 360° 165° 8°N -1, 9 114° and list SHA, RA, dec and magnitude for each. Saturn 360° 253° 22°N +0, 1 172° Rounded to 107° 217° Plot the sun and moon for the same time and list GHA, RA and dec for each. Find LHA Aries? 9

Question 7 b Use the Excerpts from the Nautical Almanac, Appendix B, for the following questions. You are at L 35°N, Lo 62°W. It is ZT 2000 on 30 June. b. Choose the bodies for a two-body and three-body twilight fix. Two-body fixes: Vega-Antares, Deneb-Moon, Pollux or Mars-Spica are all reasonable. Three-body fixes: Deneb-Antares-Regulus, Moon-Spica-Regulus. 10

Question 7 c Use the Excerpts from the Nautical Almanac, Appendix B, for the following questions. You are at L 35°N, Lo 62°W. It is ZT 2000 on 30 June. c. What is the sun’s azimuth at sunset? At sunrise? At sunset, Sun Zn is 298°. At sunrise, Sun Zn is 062°. 11

Question 7 d Use the Excerpts from the Nautical Almanac, Appendix B, for the following questions. You are at L 35°N, Lo 62°W. It is ZT 2000 on 30 June. d. Is the approximate altitude of the sun at meridian transit determined by the blue overlay reasonable for a sight? n At meridian transit, altitude of the sun is 78°. This is a high altitude sight, so care must be taken to make an accurate observation. 12

Question 7 e Use the Excerpts from the Nautical Almanac, Appendix B, for the following questions. You are at L 35°N, Lo 62°W. It is ZT 2000 on 30 June. e. Were the sun and moon available for a 2 body fix earlier in the day on 30 June? n No sun-moon fix is possible. The sun is setting as the moon is rising. 13

Question 7 f Use the Excerpts from the Nautical Almanac, Appendix B, for the following questions. You are at L 35°N, Lo 62°W. It is ZT 2000 on 30 June. f. From the Almanac, what is the time of meridian transit of Venus on 30 June? Do you expect it to be visible during the daylight? n MT is at ZT 1007. It is 2 hrs 5 minutes away from MT of the sun and its magnitude is such that it should be visible in the daytime. 14

Question 7 g Use the Excerpts from the Nautical Almanac, Appendix B, for the following questions. You are at L 35°N, Lo 62°W. It is ZT 2000 on 30 June. g. Due to cloud cover at twilight, the only bodies available for observation that evening were Antares and a bright body low on the eastern horizon. What is that body? n With the 35° N blue template set at evening twilight, the only bright body low in the east is Altair. 15

Question 8 -a With a DR position of L 35°S, Lo 165°W on 20 March, plan a running fix with an LOP of the sun a a. What is the azimuth of the sun at transit and short time before transit and a meridian transit LHA Aries when the sun is at transit? LOP. An azimuth cut of 45° between the LOPs should be adequate. The Nautical Almanac indicates that MT will occur at 1207 for your Using the Star Finder: Zn = 000°, LHA Aries= longitude, so plot the sun on your star finder at ZT 001° (By inspection) 1207. Answer the following questions, first using the star finder, then with Celestial Tools (when Using Celestial tool: Zn = 360°, LHA Aries = using Celestial Tools, use the date 20 Mar 2004). 001° 16

Question 8 -b With a DR position of L 35°S, Lo 165°W on 20 When the azimuth of the sun is 045°, what is the March, plan a running fix with an LOP of the sun a short time before transit and a meridian transit LHA of Aries? LOP. An azimuth cut of 45° between the LOPs should be adequate. The Nautical Almanac indicates that MT Star Finder : 332°will occur at 1207 for your longitude, so plot the sun on your star finder at ZT Celestial tool : 331° Solution : Zn 045° occurs 1207. Answer the following questions, first using from 1004 to 1010. Using midpoint 1007, LHA the star finder, then with Celestial Tools (when Aries = 331° using Celestial Tools, use the date 20 Mar 2004). 17

Question 8 c With a DR position of L 35°S, Lo 165°W on 20 March, plan a running fix with an LOP of the sun a What is the difference between this LHA Aries and short time before transit and a meridian transit the LHA of Aries at LAN? LOP. An azimuth cut of 45° between the LOPs should be adequate. The Nautical Almanac Star Finder: 29° indicates that MT will occur at 1207 for your longitude, so plot the sun on your star finder at ZT 1207. Answer the following questions, first using Celestial tool: 30°. Solution : (360°-331°) + the star finder, then with Celestial Tools (when 001° = 30° using Celestial Tools, use the date 20 Mar 2004). n 18

Question 8 d With a DR position of L 35°S, Lo 165°W on 20 March, plan a running fix with an LOP of the sun a What is the LHA difference, converted to time? short time before transit and a meridian transit LOP. An azimuth cut of 45° between the LOPs should be adequate. The Nautical Almanac Star Finder : 1 hour 56 minutes. indicates that MT will occur at 1207 for your Solution : 29° X 4 m/degree= 116 minutes/60 = longitude, so plot the sun on your star finder at ZT 1 hour 56 minutes. 1207. Answer the following questions, first using the star finder, then with Celestial Tools (when Celestial tool: 2 hours. Solution : 30° X using Celestial Tools, use the date 20 Mar 2004). 4 min/degree = 120 min/60 = 2 hours 19

Question 8 e With a DR position of L 35°S, Lo 165°W on 20 With transit occurring at 1207, when should you take March, plan a running fix with an LOP of the sun the earlier sight? a short time before transit and a meridian transit LOP. An azimuth cut of 45° between the LOPs should be adequate. The Nautical Almanac Star Finder : 1011. Solution 1207 – 0156 = 1011 indicates that MT will occur at 1207 for your longitude, so plot the sun on your star finder at Celestial tool: 1007. Solution : 1207 – 2 hours = 1007 ZT 1207. Answer the following questions, first (Zn = 045°) using the star finder, then with Celestial Tools (when using Celestial Tools, use the date 20 Mar 2004). n n 20

Question 8 f After meridian passage, you can do the same thing With a DR position of L 35°S, Lo 165°W on 20 to obtain another running fix. At what time should March, plan a running fix with an LOP of the sun a you take the afternoon sight? short time before transit and a meridian transit LOP. An azimuth cut of 45° between the LOPs should be adequate. The Nautical Almanac indicates that MT will occur at 1207 for your Star Finder: 1403. Solution : 1207 + 0156 = longitude, so plot the sun on your star finder at ZT 1403 1207. Answer the following questions, first using the star finder, then with Celestial Tools (when Celestial tool: 1407. Solution : 1207 + 2 hours using Celestial Tools, use the date 20 Mar 2004). = 1407 (Zn = 315) 21

Sight Planning End of Global Navigation Chapter 6 22