A quick how to, please

[Twister_Ken]

How do I calculate the angular height of the sun above the horizon, and its compass bearing, at various times on various dates. My almanac has some tables, but the explanation may well have been translated from the original Japanese by a Turk whose second language is Swahili.

This has got nothing to do with nav, it's actually to try and calculate the shadows that will be cast by a tall building proposal.

Many thanks in advance.

 

[claymore]

It comes up through the middle pane of our back kitchen window right through the summer as I'm filling the kettle at 06:45hrs - just now its gone through the 3rd pane from the left in the conservatory. The distance is around 9ft between these panes although that is an estimate and I could measure it when I get home f you wish. Anyway the angle seems to be around 43 degrees. Again an estimate and I could measure etc.
There was a complicated issue some time ago to which you responded which involved a bucket of water, might be a good place to start?
Failing the scientific approach outlined above, what about commisioning forum members to find a high building near them and get them to report back re- the length of shadows. Hope this helps
Archimedes.

 

[30boat]

(shift)sin(sinLxsinD+cosLxcosDxcosH)
L=lat
D=dec(minus if dif. name from Lat)
H=Lha(minus if larger than 180º)
This is for true alitude .
Since you want aparent altitude you will need to add height of eye correction wich will of course be relative to the height above sea level of the place you're intersted in.This you can probably get from the almanac .
As for bearing I can send you copies of my tables (Portuguese) wich are very easy to use.You only need to know the Sun's declination and your Lat.

 

[Laurence]

You may well have already considered the very simple solution of holding a stick of known length (say one metre) vertically with one end touching the ground in the same vicinity as the building and measuring the length of its shadow. From this you can deduce the length of the shadow of the proposed building.

 

[Twister_Ken]

Laurence - The stick method is simple, but I need to do some predictive work - different times of day, different days of year, etc.

 

[Guest]

Can't help you immediately with your problem, but can recomend a wonderful book that has solutions to most navigation and geometric problems raised in this forum. The title is "Mathematics for the Million", author Lancelot Hogben, last pulished in 1947. Probably find it in a second hand bookshop, but seriously it is a great read for anyone interested solving mathematical problems.

 

[Guest]

AP 3270 ..... Air Navigation Tables, Epoch 2000

+

A copy of Nories or Burtons Tables.

Both are available at your local Chart / Chandlers that supplies Commercial Shipping. Bewrae they are expensive but nice - as Mr Kipling says !

The altitude is of course a sun sight basically, and the bearing from same or can be simpler from ABC tables- which is the traditional 'Compass Error' calculation.

You will of course need a bit of Nav text book help, but I think the Nories. Burtons and AP3270 actually do spell out the methods inside !

Failing all that - you could borrow or buy a Tamaya Nav Calculator .... expensive though !!!!!

Good luck .... (I use a Texas Instruments Ti59 Nav Calculator personally !!!!! along with a Nautical Almanac ......)