Gee that sounds too much like math. So the first problem I see is your question is based on alt-azimuth coordinates (10 edge above horizon, how far from east) and ephemeris data is in declination-right ascension coordinates. This makes your problem much harder to solve. Ephemeris data is very hard to calculate which is why historically it was published in tables and in modern times it is done by computer. Computers have a pretty easy time going from ra-dec to alt-az for a given location. Ephemeris.com uses the nasa JPL data as its source. JPL does give instructions on calculating position using Kepler laws of planetary motion. http://ssd.jpl.nasa.gov/?planet_pos This is based on math from the 1600's and not as precise as modern computer models, but apparently was close enough to have Kepler's mother tried for witchcraft. Using a modern astronomy planetarium program it's pretty simple to pick a date and location, display the alt-az for your object then step through time until it reaches the height your interested in. On Fri, Jul 31, 2015 at 7:06 AM, Ed <utnatsedj1@xmission.com> wrote:
Joel, Thank you for responding. What I am interested in is learning how to use an ephemeris calculator to solve problems similar to the example I gave. I don't need answers to an accuracy necessary to point a telescope at the center of the moon, I was just wondering could that kind of problem be solved with information available on ephemeris.com. Thanks for your help, Ed Quoting Joel Stucki <joel.stucki@gmail.com>:
Well if the date is tonight, it will be at 9:09 and it will be at azimuth 121 04' 7.5" which is in the SE. About 31 degrees from due east. Pretty easy with software.
On Thu, Jul 30, 2015 at 6:09 PM, Ed <utnatsedj1@xmission.com> wrote:
Help! Can anyone tell me how, or where I can find out how, to use an ephemeris calculator (like ephemeris.com) for the Moon to figure this out? How many degrees north or south of due east will the Moon be when it is 10 degrees above the horizon on a specific date, at a specific lat/long location approximately 70 miles west of SLC, and at what time that will occur? An iterative solution method would be acceptable, if a direct calculation is not possible. I would appreciate any help that anyone can provide. Ed Stimpson _______________________________________________ Utah-Astronomy mailing list http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Send messages to the list to Utah-Astronomy@mailman.xmission.com The Utah-Astronomy mailing list is not affiliated with any astronomy club. To unsubscribe go to: http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Then enter your email address in the space provided and click on "Unsubscribe or edit options".
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