leonard_evens Posted July 4, 2003 Share Posted July 4, 2003 Where can I find information about the position of the sun in the sky as a function of latitude, date, and time of day? I tried a search on "altitude and azimuth", but it referred me to a previous posting that I was denied access to for some reason. There was also a reference to a US Navy site, but I was also denied access to that. I hope I don't have to write my own program to derive the appropriate information. I did find some reference to Palm Pilot programs, but I don't have such a PDA, and I would rather not have to carry one with me in the field anyway. I understand generally about the path the sun takes in the sky, but I am having a little trouble visualizing it three dimensionally. Can anyone recommend a reference for a refresher course on such matters? Link to comment Share on other sites More sharing options...
charles_stobbs2 Posted July 4, 2003 Share Posted July 4, 2003 See Gallileo Link to comment Share on other sites More sharing options...
jeff_schraeder1 Posted July 4, 2003 Share Posted July 4, 2003 Try looking at a nautical almanac. It will have the altitude and azimith of the sun listed on a minute by minute basis. You need to know your location (latitude) and the time. They are relatively inexpensive but are date specific so you need a new one every year. Link to comment Share on other sites More sharing options...
jeff_schraeder1 Posted July 4, 2003 Share Posted July 4, 2003 http://aa.usno.navy.mil/data/docs/AltAz.html Try this site. The computed tables give the azimuth and altitude in 10 minute intervals. Negative numbers in the altitude indicate that the sun is below the horizon. Link to comment Share on other sites More sharing options...
alex_hawley Posted July 4, 2003 Share Posted July 4, 2003 Leanord, I did a quick Google search for "navigation tables" and found this: National Imagery and Mapping Agency (NIMA) Maritime Safety Information Division http://pollux.nss.nima.mil/index/index.html I didn't delve into the site at all but it may get you the information you need for altitude and azimuth of the sun at a specific location. The standard reference used by the US Navy to explain all this is "American Practical Navigator (Bowditch)". Here's another link that has some of the typical stuff used in celestial calculations and also offers Bowditch for sale. http://www.waypoints.com/celestialsupplies.html Calculating sunrise and sunset times by hand is not too difficult. Both the US Navy and Royal Navy publish tables each year to do this. The Local Apparent Noon, the time of day when the sun is at its highest, follows from sunrise and sunset. The azimuth angle is a bit more difficult and time consuming. Believe me, being able to get this info from the 'net or a computer program is MUCH easier than doing it by hand from the tables. Have fun and good luck! Link to comment Share on other sites More sharing options...
skygzr Posted July 4, 2003 Share Posted July 4, 2003 Hi Leonard � The Naval Observatory publications are helpful if you�re an astronomer, but might be confusing otherwise. If the basic movement of the sun confuses you, then tables of coordinates might not be quite the ticket. I assume you�re in the Northern Hemisphere. If you face south, the sun will rise on your left and set on your right. It will reach it�s highest at roughly 1:00 PM (not noon, because of daylight savings time). In the summer, the sun rises in the northeast (or slightly behind you if you�re still facing south) and sets in the northwest. In the winter, the sun rises in the southeast and sets in the southwest and makes a lower path in the sky. From the tropics, the sun rises nearly due east and sets nearly due west and passes high overhead all year long. From the southern hemisphere the sun moves right to left as you face north. If this didn�t help, visit your local library and browse through entry level astronomy texts�.one will surely have some pictures that will help you. I teach astronomy part time at the local college and I know that visualizing (and explaining!) the movements of the sun and stars is sometimes difficult. I carry a $3 compass with me so I can predict where the sun and moon will be. It�s helped me many times. Link to comment Share on other sites More sharing options...
conrad_hoffman Posted July 4, 2003 Share Posted July 4, 2003 The astronomy folks have lots of programs for this. Do a Google search on something like planetary position and location in sky. Most of the software that does planets also does the sun and moon. Link to comment Share on other sites More sharing options...
leonard_evens Posted July 4, 2003 Author Share Posted July 4, 2003 Charles, Or I could try Ptolemy instead. He had the geometry wrong, but for calculations his geometry would work just as well as Galileo's, perhaps better. More seriously, I managed to find some sites myself doing a google search of the net for "position of sun in the sky". One at www.helioclim.net/com/appletsolargeom/AppletSolar_en.html has a Java applet which gives a graph showing the altitude as a function of solar time. The altitude and azimuth are given numerically as you move the cursor across the time axis. Unfortunately, with my browser and the current version of Java it is using, some of the fields are overwritten with text, so it is a bit hard to use. I'm not sure why my original google search yielded so little. I've also found other sites giving all the relevant formulas, and if I get interested enough, I can write my own software to do what I want. It would still be nice to see something with detailed three dimensional diagrams showing how the the correct (Coperinican) picture relates to the Ptolemaic picture of the sun moving about the Earth. The latter is what you see when you look up in the sky. I understood that completely at one point in all its subtle detail, but age and time take their toll. Jeff, The site you referred me to gives me a firewall error. I am behind a DSL/Cable router which provides a firewall of sorts through network address translation (NAT), but it shouldn't prevent packets from a distant web site from getting through. I think the problem is at the Navy web site. Either it isn't letting any non authorized users through or something about packets coming from a NAT system can't get through. I would be curious to know if others can get through. Link to comment Share on other sites More sharing options...
ralph_barker Posted July 4, 2003 Share Posted July 4, 2003 <p>Here are a couple of links that I find handy:</p> <p><a href="http://www.srrb.noaa.gov/highlights/sunrise/azel.html">NOAA solor position calculator</a></p><p>and, <a href="http://www.srrb.noaa.gov/highlights/sunrise/sunrise.html">NOAA Sunrise/Sunset calculator</a></p> Link to comment Share on other sites More sharing options...
rick_jones5 Posted July 4, 2003 Share Posted July 4, 2003 Redshift is a mutimedia astronomy program available I believe from Amazon and other book sellers. I have version 4. While it provides a lot more information than you may want it will allow you to position yourself anywhere on the planet, pick any date, anytime of day and show you the position of the sun, 250,000 other stars, asteroids, comets and 40,000 deep sky objects. You can place a pointer on the sun or any other object and it will provide exact coordinates. Like I said, maybe a bit of overkill but, who knows, you might find it pretty fascinating as I have. Link to comment Share on other sites More sharing options...
jeff_schraeder1 Posted July 4, 2003 Share Posted July 4, 2003 Leonard,I'm also NAT addressed from behind a DSL router/modem. I have no trouble. You might want to check your router settings. Link to comment Share on other sites More sharing options...
leonard_evens Posted July 4, 2003 Author Share Posted July 4, 2003 About access to aa.usno.navy.mil: This is getting stranger and stranger. I have three computers, runing Linux and Windows, two of which as dual boot, all connected to my DSL/Cable router. I can't see anything about the router settings that could affect the situation, and I don't believe I've ever had this problem with a publicly available website. I've tried Windows 98 and Linux on each of two computers. I've tried Mozilla, which is similar to Netscape, and I've tried both Netscape and Internet Explorer. In all cases but one, I was denied access to the site. The one success was using IE, but when I tried again with IE, I was again denied access. I wonder if some other people could try it with different browsers to see if I am unique. The only thing that occurs to me is that the site may have problems with browsers other than IE and after one attempt with a non-IE browser it excludes that IP address for some period of time. Link to comment Share on other sites More sharing options...
tim_atherton2 Posted July 4, 2003 Share Posted July 4, 2003 I can't get onto it either Link to comment Share on other sites More sharing options...
allen_whittier Posted July 4, 2003 Share Posted July 4, 2003 The last time I needed that info I called my local planetarium. Astronomers have great tables for where and when thing are located in the sky. I associate with astronomers and know there are quite a few programs out there that work everything out. Check for a local astronomy club or store. Link to comment Share on other sites More sharing options...
john_cook1 Posted July 4, 2003 Share Posted July 4, 2003 You're right, Leonard. I've been using this site every few weeks for two years without a problem. Now, all of a sudden, the Navy is verbotten. Guess we all can't be too careful, now that the burnoose is loose... Link to comment Share on other sites More sharing options...
leonard_evens Posted July 4, 2003 Author Share Posted July 4, 2003 I guess bin Laden might use the information he could obtain from the Naval Observatory to focus an enormous magnifying lens on the White House. ;-) Link to comment Share on other sites More sharing options...
ardea Posted July 4, 2003 Share Posted July 4, 2003 I'm unable to access the Navy site also. I have used it in the past. The Nautical Almanac will not give the information you seek unless you solve a sight reduction problem in which case you would not need the Almanac. I believe the magazine "outdoor Photographer" publishes the info you seek...Richard Link to comment Share on other sites More sharing options...
ann_m Posted July 4, 2003 Share Posted July 4, 2003 I did a cut & paste of Jeff's link and got in no problem.... it's the Astronomical Application Dept. with Form A & Form B Table Computors .... right? Link to comment Share on other sites More sharing options...
henry_a Posted July 5, 2003 Share Posted July 5, 2003 http://aa.usno.navy.mil/data/docs/RS_OneDay.html Works for me. Link to comment Share on other sites More sharing options...
tim_atherton2 Posted July 5, 2003 Share Posted July 5, 2003 You are not authorized to view this page You might not have permission to view this directory or page using the credentials you supplied. -------------------------------------------------------------------------------- If you believe you should be able to view this directory or page, please try to contact the Web site by using any e-mail address or phone number that may be listed on the aa.usno.navy.mil home page. You can click Search to look for information on the Internet. HTTP Error 403 - Forbidden Internet Explorer Link to comment Share on other sites More sharing options...
leonard_evens Posted July 5, 2003 Author Share Posted July 5, 2003 To those of you who managed to connect to the Naval Observatory, You might try again. I did manage to connect once, but I haven't any other time despite numerous attempts. I think there is a problem with the site or perhaps its link to some ISPs Link to comment Share on other sites More sharing options...
bob. Posted July 5, 2003 Share Posted July 5, 2003 If I try from home (cable - *****.co.uk) I get refused. If I log on to a server at work (DSL - *****.com) and try it from there, I get in OK... The server at work runs NAT through a firewall, my home PC gets an IP address from the ISP (although I run it through Zonealarm - but I get the same result if I shut down ZA). Looks like it may be filtering based on IP addresses or possibly reverse DNS lookup (as the work firewall has an entry in DNS & my home PC does not). Anyway - I came across a program called MoonCalc which is as the name suggests intended for tracking the moon, but it also has displays data for the Sun too. No graphics for the Sun transit tho.... http://www.starlight.demon.co.uk/mooncalc/ Cheers, Link to comment Share on other sites More sharing options...
robert_a._zeichner1 Posted July 5, 2003 Share Posted July 5, 2003 The software you need is SunPath. This is what professional motion picture dp's use. Check it out. Just do a google search for SunPath and you'll be there. Link to comment Share on other sites More sharing options...
henry_a Posted July 5, 2003 Share Posted July 5, 2003 I've had the link I gave earlier bookmarked for years, use it fairly frequently and don't remember ever being denied. You might try another browser? Link to comment Share on other sites More sharing options...
mark_sampson Posted July 7, 2003 Share Posted July 7, 2003 There's a program, I think called "Sunpath", designed by a movie director for the location filmmaking industry. I know someone who uses it, and have seen it in operation- works quite well. I'd bet that it's just what you need. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now