Click Here to
Order this information in Print

Click Here to
Order this information on CD-ROM

Click Here to
Download this information in PDF Format

 

Click here to make tpub.com your Home Page

Page Title: Amplitude of the Sun, Continued
Back | Up | Next

Click here for a printable version

Google


Web
www.tpub.com

Home

   
Information Categories
.... Administration
Advancement
Aerographer
Automotive
Aviation
Combat
Construction
Diving
Draftsman
Engineering
Electronics
Food and Cooking
Math
Medical
Music
Nuclear Fundamentals
Photography
Religion
USMC
   
Products
  Educational CD-ROM's
Printed Manuals
Downloadable Books

   


 

Amplitude of the Sun, Continued Labeling the Amplitude The  amplitude  of  a  body  is  given  the  prefix  E  (east)  if  the  body  is  rising and  the  prefix  W  (west)  if  the  body  is  setting.  Additionally,  the amplitude  of  a  body  is  given  the  suffix  N  (north)  if  the  body  has northerly  declination  and  the  suffix  S  (south)  if  it  has  southerly declination. Finding Amplitude  of the Sun Using the  Celestial Horizion As  discussed  above,  the  amplitude  of  a  body  can  be  taken  directly  from table  27  of  Bowditch,  Volume  II,  if  the  body  is  observed  when  its  center is  on  the  celestial  horizon.  Since  the  Sun  is  most  commonly  used  for amplitudes,  it  will  be  the  topic  of  our  discussion. Gathering  Information:  To  observe  the  Sun  when  it  is  on  the  celestial horizon,  its  lower  limb  must  be  about  two-thirds  of  the  diameter  above the  visible  horizon.  You  must  know  the  Greenwich  mean  time  (GMT) of  your  observation  to  determine  the  Sun’s  declination  from  the  right- hand  daily  pages  of  the  Nautical  Almanac,  your  DR  Lat.  at  the  time  of observation,  and  the  true  bearing  of  the  Sun  as  observed  using  a telescopic  alidade. Example Problem The  DR  latitude  of  your  ship  is  51°04.6'N.  The  declination  of  the setting  Sun  was  19°00.4'N.  Your  true  bearing  (as  observed  by  a telescopic  alidade)  to  the  Sun  was  300°. From  this  known  information,  we  can  use  table  27  of  Bowditch  to determine  the  amplitude. Figure  9-7  shows  an  excerpt  from  table  27.  By  inspection  of  figure  9-7, you  can  see  that  you  must  enter  the  left-hand  column  with  your  ship’s DR  latitude.  You  can  also  see  that  the  Sun’s  declination  is  listed  across the  top  of  the  table.  Since  latitude  51°  and  declination  19°  are  closest  to our  entering  values,  we  determine  that  the  amplitude  of  the  Sun  when  it is  on  the  celestial  horizon  is  31.2°.  Now  that  we  have  the  amplitude, what  do  we  do  with  it?  First  of  all,  there  are  some  basic  rules  that  must be  applied  that  relate  to  our  previous  discussion  of  the  assigned  prefix and  suffix  of  an  amplitude.  Our  amplitude  was  taken  when  the  Sun  was setting,  and  its  declination  name  is  north.  Using  the  rules  for  labeling the  amplitude,  we  label  the  amplitude  as  follows:  W  31.2°  N.  We  use W  because  the  Sun  is  setting  and  N  because  the  Sun’s  declination  is  N. 9-13

Privacy Statement - Press Release - Copyright Information. - Contact Us - Support Integrated Publishing

Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business