|
|
|
Thread Tools | Display Modes |
#11
|
|||
|
|||
M Holmes emailed this:
My brother is a cinematographer and needs a Solar Position and Sunrise Sunset calculator for his Apple computer. You enter long/lat, timezone + daylight savings, altitude, etc. and it gives you the figures. Shouldn't be too hard to do on a calculator: The angle between the southern meridian and sunset/sunrise on a flat horizon is given by: Cosine (angle) = minus Tangent (Latitude) multiplied by Tangent (Declination of Sun) So what you need is some tables of the Sun's declination for the year and you can get the angle. Then you need the difference between Noon and the Sun's transit of the southern meridian at your longitude, which can be calculated from the longitudinal difference from your location and the longitudinal meridian for your time zone. I have vague memories that you may need to apply an Equation of Time correction (someone here will probably know?) and so you may need EoT tables. Don't forget to correct for British Summer Time too... Very funny. What fun that would be working out the sunrise, sunset, daylight hours, etc. for a two month shoot in ten different locations. Thanks anyway, MS |
#12
|
|||
|
|||
In uk.sci.astronomy MS wrote:
M Holmes emailed this: Very funny. What fun that would be working out the sunrise, sunset, daylight hours, etc. for a two month shoot in ten different locations. Well, some folks prefer to understand what they're calculating rather than just take the numbers from the magic box. YMMV. Thanks anyway, No probs. FoFP -- Then the Gods of the Market tumbled, and their smooth-tongued wizards withdrew And the hearts of the meanest were humbled and began to believe it was true That All is not Gold that Glitters, and Two and Two make Four And the Gods of the Copybook Headings limped up to explain it once more. |
#13
|
|||
|
|||
seen Ashworth?
|
#14
|
|||
|
|||
~ * Music for Torching ...
As A.M. Homes's incendiary novel unfolds, The Kodacolor hues of the good life become nearly hallucinogenic. http://www.powells.com/biblio?isbn=068817762x |
#15
|
|||
|
|||
.... although
A Country of Mothers I prefer ... |
#16
|
|||
|
|||
MS wrote:
Many, many thanks, it is perfect! One question, what's EOT? EG. The display looks like this: Sunrise 0610 Sunset 1831 Transit 1220 EOT 6:48 min:sec "Equation of Time". It's explained at the Analemma site: http://www.analemma.com/Pages/Summation/SummationEffect/Summation.html (and elsewhere!) but in a nutshell it's how long before or after mean solar noon the Sun transits the meridian, due to the ellipticity of the Earth's orbit and the inclination of its axis. It never amounts to more than about a quarter of an hour's difference, whether early or late. -- Odysseus |
#17
|
|||
|
|||
Thanks for the explaination.
Odysseus emailed this: MS wrote: Many, many thanks, it is perfect! One question, what's EOT? EG. The display looks like this: Sunrise 0610 Sunset 1831 Transit 1220 EOT 6:48 min:sec "Equation of Time". It's explained at the Analemma site: http://www.analemma.com/Pages/Summation/SummationEffect/Summation.html (and elsewhere!) but in a nutshell it's how long before or after mean solar noon the Sun transits the meridian, due to the ellipticity of the Earth's orbit and the inclination of its axis. It never amounts to more than about a quarter of an hour's difference, whether early or late. |
#18
|
|||
|
|||
Very funny. What fun that would be working out the sunrise, sunset,
daylight hours, etc. for a two month shoot in ten different locations. Well, some folks prefer to understand what they're calculating rather than just take the numbers from the magic box. YMMV. Don't get me wrong, I shouldn't have been sarcastic (I meant it to be humerous), it's good to understand these things. One of the beauties of computers is they can take the tedium out of what would be a very time consuming set of calculations, which if done manually may result in the occasional error and when shooting a film an hour lost sunlight could be a costly mistake. Thanks, MS |
#19
|
|||
|
|||
MS wrote in
.uk: Very funny. What fun that would be working out the sunrise, sunset, daylight hours, etc. for a two month shoot in ten different locations. Well, some folks prefer to understand what they're calculating rather than just take the numbers from the magic box. YMMV. Don't get me wrong, I shouldn't have been sarcastic (I meant it to be humerous), it's good to understand these things. One of the beauties of computers is they can take the tedium out of what would be a very time consuming set of calculations, which if done manually may result in the occasional error and when shooting a film an hour lost sunlight could be a costly mistake. If Johannes Kepler had known about electronic calculators he would have killed for one (well not really). Imagine doing the calculations required to produce the Rudolphine tables by hand. He thought he was really lucky that Napier had come up with the idea of logarithms being used to speed up multiplication and division via a set of tables. Klazmon. Thanks, MS |
|
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Solar Position / Sunrise Sunset calculator. | MS | Misc | 18 | September 22nd 05 11:46 PM |
PDF (Planetary Distance Formula) explains DW 2004 / Quaoar and Kuiper Belt | hermesnines | Astronomy Misc | 10 | February 27th 04 02:14 AM |
Solar flares: is iron-rich sun the cause? (Forwarded) | Andrew Yee | Astronomy Misc | 1 | November 19th 03 08:20 PM |
Voyager 1 Approaches Solar System's Outer Limits | Ron Baalke | Science | 0 | November 5th 03 06:53 PM |
ESA Sees Stardust Storms Heading For Solar System | Ron Baalke | Science | 0 | August 20th 03 08:10 PM |