PDA

View Full Version : Sun and Moon Position



twinmarlin
2008-Nov-18, 03:44 AM
I'm not good at all at astronomical formulas but am very good at Excel. With that in mind: Given the RA and DEC of the sun and/or moon and the Latitude and Longitude of the position on the planet, is there a formula I can put into an Excel spreadsheet that will return the Azimuth and Altitude of the sun and/or moon as seen from that position on the planet? Any help would be appreciated.
Thanks, Tom

jlhredshift
2008-Nov-18, 04:29 AM
I'm not good at all at astronomical formulas but am very good at Excel. With that in mind: Given the RA and DEC of the sun and/or moon and the Latitude and Longitude of the position on the planet, is there a formula I can put into an Excel spreadsheet that will return the Azimuth and Altitude of the sun and/or moon as seen from that position on the planet? Any help would be appreciated.
Thanks, Tom

This book (http://www.amazon.com/Astronomical-Algorithms-Jean-Meeus/dp/0943396611/ref=sr_1_1?ie=UTF8&s=books&qid=1226982431&sr=1-1) has it all.

tabijadoon
2009-Mar-02, 07:45 AM
I am doing research on earthquake prediction with the help of planet alignment....................any one have some knowledge kindly mail me at geotabijadoon@yahoo.com.
Waiting for help

mfumbesi
2009-Mar-03, 12:59 PM
Ahem...
He wants help on his homework...hehehehe!!!

Amber Robot
2009-Mar-03, 02:07 PM
Ahem...
He wants help on his homework...hehehehe!!!

In college I did essentially what he's asking for and I used a spreadsheet program, so I know it can be done.

Centaur
2009-Mar-04, 10:17 PM
I'm not good at all at astronomical formulas but am very good at Excel. With that in mind: Given the RA and DEC of the sun and/or moon and the Latitude and Longitude of the position on the planet, is there a formula I can put into an Excel spreadsheet that will return the Azimuth and Altitude of the sun and/or moon as seen from that position on the planet? Any help would be appreciated.
Thanks, Tom

Indeed, the Meeus book mentioned by jlhredshift has the required formulae. What you have is mainly a trigonometry problem. Much of that is spherical trigonometry. You did not mention another necessary input item: the time. In particular, the sidereal time must be determined. This is needed in order to know the objectís hour angle, which is the sidereal time minus the objectís right ascension. If you have that information but not the formulae, then just consider the problem to be an exercise in trigonometry. Since you are a first time poster, I suspect you are presenting us with a homework problem and we will never hear from you again. Your teacher wants you to perform the trigonometry, so just do it.

twinmarlin
2009-May-26, 02:50 PM
Indeed, the Meeus book mentioned by jlhredshift has the required formulae. What you have is mainly a trigonometry problem. Much of that is spherical trigonometry. You did not mention another necessary input item: the time. In particular, the sidereal time must be determined. This is needed in order to know the objectís hour angle, which is the sidereal time minus the objectís right ascension. If you have that information but not the formulae, then just consider the problem to be an exercise in trigonometry. Since you are a first time poster, I suspect you are presenting us with a homework problem and we will never hear from you again. Your teacher wants you to perform the trigonometry, so just do it.

Well Centaur, you couldn't be more wrong about me being a student although I did get a good chuckle of the thought of me being a student trying to cheat. No, I'm a 51 year old meat cutter. I write Visual Basic programs as a hobby and astronomy has always been a hobby of mine. I'm just writing a very simple program that positions the sun, (or the earth's shadow), in the middle of my screen and the moon's position relative to the sun (or earth's shadow). I got this idea because I just was curious as to how close the moon gets to the sun during new moon or how close to shadow during full moon. In other words to see how much we missed an eclipse this month. I do have a spreadsheet that gives all the other info I need that you mentioned, however the formulas are not providing the proper results. I use the upcoming 2017 total eclipse of the sun as a test and it doens't even come close. So if someone has done the work and put it into a simple spreadsheet, I'd be more than happy to pay for the sheet so I can use it in my program. Trust me, I'm not a professional programmer, I'm just writing the program for my personal use but of course would be willing to sign any disclaimers. Thanks for any help.

Centaur
2009-May-26, 06:54 PM
Well Centaur, you couldn't be more wrong about me being a student although I did get a good chuckle of the thought of me being a student trying to cheat. No, I'm a 51 year old meat cutter. I write Visual Basic programs as a hobby and astronomy has always been a hobby of mine. I'm just writing a very simple program that positions the sun, (or the earth's shadow), in the middle of my screen and the moon's position relative to the sun (or earth's shadow). I got this idea because I just was curious as to how close the moon gets to the sun during new moon or how close to shadow during full moon. In other words to see how much we missed an eclipse this month. I do have a spreadsheet that gives all the other info I need that you mentioned, however the formulas are not providing the proper results. I use the upcoming 2017 total eclipse of the sun as a test and it doens't even come close. So if someone has done the work and put it into a simple spreadsheet, I'd be more than happy to pay for the sheet so I can use it in my program. Trust me, I'm not a professional programmer, I'm just writing the program for my personal use but of course would be willing to sign any disclaimers. Thanks for any help.

Well I was wrong; you did come back six months later. Welcome back! Let's hope we hear more from you. Forgive us, but more often than not first time posters with a math problem are seeking the answers to a homework assignment, and we never hear from them again with even a thank you. Nevertheless, we try to point them in the right direction without actually laying out the answer. I too am an amateur astronomer and amateur software designer who likes to perform tasks similar to those you propose. As we have said, Jean Meeusí Astronomical Algorithms has the formulae you seek. Some of them are rather complex. Since you waited six months to reply, I suppose youíd be willing to wait a few more days for an online bookseller to send you a copy: http://www.amazon.com/exec/obidos/ASIN/0943396611/crastro-20

twinmarlin
2009-May-26, 09:12 PM
OK. Thanks for the info. I'll give that book a try. I appreciate it.
Tom