Hi all,

Just failed the CNav paper with a score of 68%.

Got this tricky question which I am thinking till now what is the correct approach

Q. If on a particular day 15 Dec(For etc) , what is the LMT for Canberra ( Lat aa.bb Long cc.cc) given that LMT at Perth ( Lat xx.xx, Long yy.yy) is 0600?

Obtained the UTC for Perth lets say 2200. after deducting the arc to time.

Obtained the difference of Canberra Long in comparison to Perth by using Long cc - Long yy.yy and add them up to Perth UTC time. Time etc 0100 UTC.

I would then add the Arc to time for Canberra to get the final answer dd.ee which is the LMT for Canberra.

Pls advise if steps are correct. Thanks

The LMT at any particular location depends only on the longitude, the latitude has nothing to do with it. The difference in longitude between Perth and Canberra is 33° (from ERSA). Each degree of longitude is equal to 4 minutes of time. So that's 132 minutes or 2 hours 12 minutes.

If you add 2 hours 12 minutes to Perth's LMT you will get Canberra's LMT. There is no need to go back to UTC to answer that question.

Hey Mate, I've got my exam next monday just wondering if you have any tips and how many questions did you end up getting ?

The exam is a 1 hour 45 minute exam with 40 marks allocated. Some questions are worth more than one mark so there will be fewer than 40 actual questions. If you know what's in the book and practice exams, you should have no problems with the exam.

Bob

Can someone just clarify this . Is it ALL PLACES ALONG THE SAME MERIDIAN WILL HAVE SAME LMT or ALL PLACES ALONG SAME LATITUDE WILL HAVE SAME LMT ?

All places on the same meridian will always have the same LMT (angle between that meridian and the prime meridian at Greenwich). However, when it comes to the LMT for an event like BOD or EOD, all places on the same latitude will have the same LMT for BOD or EOD on any given date. (see page 38 of the NAV book).

As the earth rotates, all places on the same latitude will experience the same duration of daylight.