pyephem

The documentation says that if pyEpehm is given a TLE and a time it will return the following. However, I'm having no luck converting the returned 'sublat' and 'sublon' to ECEF XYZ and back to LLA coordinates to verify. When I convert back the longitude is preserved but the latitude is off by about ~20 degrees for different tests. I am using functions that are verified with GPS ephemeris and I am very confident that the LLA to ECEF and back works for those parameters. Something else is going on here. Does anybody know if 'sublat' and 'sublon' are given in geocentric?? On artificial satellites,

I am new to PyEphem and I am trying to figure out what it can do and how it works. As I do not want to use it as a black box and blindly trust whatever figure I get, I wanted to recreate an example that is explained here . The example calculates the azimuth and altitude of an object for a given observer on the 10th August 1998 at 23:10 UT. The following parameters are given: RA = 16 h 41.7 min, DEC = 36 d 28 min The observer's latitude is 52 d 30 min North and longitude 1 d 55 min West. The correct answer according to the example (which I can recreate in Excel) is AZ = 269.14634 degrees and

I've a query on the results given by the PyEphem module relating to Observer() queries, and the effects of elevation. I understand from a couple of sources (such as http://curious.astro.cornell.edu/question.php?number=388 ) that the elevation of the observer has a marked effect on sunset time. However in the following code, I see next to no difference: import ephem emphemObj = ephem.Observer() emphemObj.date = '2011/08/09' emphemObj.lat = '53.4167' emphemObj.long = '-3' emphemObj.elevation = 0 ephemResult = ephem.Sun() ephemResult.compute(emphemObj) print "Sunset time @ 0m: " + str(emphemObj

I'm trying to generate the longitudes of planets. I've used the swiss ephemeris dll to do all my hard work. However to my misfortune the values generated by swiss ephemeris for the sidereal mode Lahiri Ayanamsha is way off (by around 25 minutes, especially for moon) from what I'm getting out of other vedic software or online portals including JuniorJyothsh I've downloaded the .se1 files(for planets and moon) and am using the very accurate Swiss Ephemeris mode. Further I've set the Sidereal mode, the Lahiri Ayanmsha Flag, Topocentric Flag. I've also set the topolgy latitude and longitude

Just got the basics of PyEphem working on my Raspberry Pi. Working really well. The approach to getting the next_pass of an object (in my case the ISS) is very useful... but I really also want to be able to take in to account the actual visual magnitude for the observer. That way I could list only the VISIBLE passes of the ISS rather than all of them. Is there some method to calculate the visual magnitude by accounting for the position of the Observer, the ISS and the Sun? Thank for any suggestions. EDIT: ANSWER Found my own answer to this question. By all means read the rest of the post for

I have been using python3 and pyephem to study celestial navigation mostly working through some calculations that would have to be done by hand in any case. For the sight reduction part I am trying to have pyephem output data comparable to the nautical almanac, mostly greenwich hour angle and declination. To get the hour angle of the first point of aries, I tried adding a body using ephem.readdb at 0.0 RA and 0.0 dec. But after reading the doc further I think this is working. #!/bin/python3 import math , ephem # zero longitude gmt_long = '0:0:0' # deg, min, sec myloc_date = ( '2012/12/02 22:00

I'm trying to write a basic python script that will track a given satellite, defined with tle's, from a given location. I'm not a asto/orbital person but am trying to become smarter on it. I am running into a problem when I try to convert the azimuth, elevation, range values to a ECEF position. I'm using PyEphem to get the observation values and spg4 to get the real location to verify. I'm also using the website, http://www.n2yo.com/?s=25544 , the verify the values. I'm getting the observed azimuth, elevation and range with: def get_ob(epoch, sv, obsLoc): site = ephem.Observer() site.lon = str

Is it possible to calculate Dawn, Dusk, and sunset times using PyEphem ? I've used PyEphem to produce day and night time, but I didn't find anything on sunset/dusk/dawn For dawn amd dusk , see pyephem documentation regarding twilight In a nutshell, dawn and dusk express the time when the center of the Sun is at a particular angle below the horizon; the angle used for this calculation varies for the definition of the "civilian", navigation (nautical) and astronomical twilights which use 6, 12 and 18 degrees respectively. In opposition the sunrise corresponds to the time when the edge of the Sun