Quantcast Timing Celestial Observations, Continued - 14220_166

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: Timing Celestial Observations, 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

   


 

Share on Google+Share on FacebookShare on LinkedInShare on TwitterShare on DiggShare on Stumble Upon
Back
Timing Celestial Observations - 14220_165
Up
Quartermaster 1 & C - Military manual for the Quartermaster rate
Next
Chapter 6 Introduction to Celestial Navigation - 14220_167
Timing Celestial Observations, Continued Techniques The  C-W  computation  is  watch  time  (WT)  to  the  half-second  subtracted from  chronometer  time  (CT).  If  WT  is  greater,  12  hours  must  be  added to  CT.  The  C-W  is  never  greater  than  12  hours  because  both  watch  and chronometer  are  graduated  only  to  12.  Now  that  you  know  the  value  of C-W, it is necessary only to add this value to the WT of any observation to  find  the  correct  CT,  then  apply  chronometer  error  (CE),  and  you  have the  GMT  (UTC)  of  the  observation. Examples To  work  an  example,  assume  that  you  have  a  chronometer  whose  error (CE)  is  -7m  4s;  in  other  words,  it  is  7m  4s  behind  GMT  (UTC).  Your watch is set to ZT and reads 5h 26m 42s when the chronometer reads 10h 19m  00s.  First,  find  the  C-W.  It’s  WT  subtracted  from  CT. CT 10h 19m 00s WT 5h 76m 42s C-W 4h 52m 18s You step out on the bridge with our sextant and watch, and sight on Sirius at  WT  5h  34m  21s,  date  15  October,  longitude  101°34.2'E.  What  should be  the  GMT  (UTC)  of  this  sight?  Applying  the  formula CT = WT + C-W, we find: WT 5h 34m 21s CE 7m 04s GMT 10h 33m 43s Now,  let’s  consider  the  date  15  October  at  101°34.2'E.  Is  it  the  same  day at  Greenwich?  Let’s  see.  The  ZT  is  5h  34m  21s.  The  ZD  is  -7.  Subtract ZD  from  ZT  to  get  GMT  (UTC).  You  can’t  subtract  7  from  5,  but  5h  on 15 October is the same as 29th on 14 October, and 7 from 29 is 22. Therefore, 1 Oh 33m 43s is not a.m. on 15 October, but p.m. on 14 October.  From  this  computation,  it  follows  that  GMT  (UTC)  is  22h  33m 43s on 14 October. In problems like these, you must check the date carefully every time to avoid a 12-hour error such as the one we encountered just now. 5-20

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

Integrated Publishing, Inc.
6230 Stone Rd, Unit Q Port Richey, FL 34668

Phone For Parts Inquiries: (727) 493-0744
Google +