pyephem

问题 I am trying to calculate the local solar time based on UTC hour and longitude. I have looked through the ephem package but was not able to identify a direct method to do so. Similar questions on this matter either evoke the calculation of fixed positions (sunrise, moon, sunset) (e.g. Calculating dawn and sunset times using PyEphem) or receive suggestions of simplified methods (e.g. Local solar time function from UTC and longitude). Is there any alternative to the aforementioned solutions?

问题 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

问题 To help me with calculating the visual magnitude of the International Space Station I need to be able to calculate the phase angle. Can anyone help me calculate that? For any moment in time I have generated the Obs object and the ISS object using PyEphem . For the observer I have the Alt/Az to the ISS and Alt/Az to the Sun... And of course I have the ISS.range (in km) from the observer. So it looks to me that I should be able to calculate the phase angle with "simple" geometry. Unfortunately,

问题 I have difficulties with finding current coordinates (RA, DEC) for star in sky. In net I have found only this one tutorial, how to use ephem library: http://asimpleweblog.wordpress.com/2010/07/04/astrometry-in-python-with-pyephem/ As I understood I need to: create observer telescope = ephem.Observer() telescope.long = ephem.degrees('10') telescope.lat = ephem.degrees('60') telescope.elevation = 200 Create a body Object star here is trouble, I have only (RA,DEC) coordinates for star Calculate

问题 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

问题 I'm trying to write a basic python scrip 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 where the different models I'm using are giving me very different position answers. I have tried using: pyEphem spg4 predict (exec system call from script) The satellites I'm testing with are the ISS and directv10 (one fixed, one moving- with internet tracking available for

问题 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 回答1: 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,

问题 Pyephem docs have example how to calculate constellation in which planet is in certain time. >>> m = ephem.Moon('1980/6/1') >>> print(ephem.constellation(m)) ('Sgr', 'Sagittarius') But how to calculate time when the planet will change constellation? 回答1: Because planets can change direction and speed across the sky, there is no way to predict ahead of time exactly when a planet will cross the boundary to another constellation. The simplest approach would be to step forward in time by one day

问题 I am trying to find out the longitude of ascending/descending moon nodes using Skyfield but unable to find any reference in documentation. Is it possible? Also do any of the JPL Files provide this data already? 回答1: It is easy to at least find them relative to the J2000 ecliptic — which might be fine for dates far from the year 2000 as well, since I think that only the definition of ecliptic longitude changes with the passing years, but not latitude (which is what the nodes care about)? In

问题 I am trying to calculate some values of satellites, the data-generation takes quite long so I want to implement this using multiprocessing. The problem is that I get this error from pyEphem, TypeError: can't pickle ephem.EarthSatellite objects . The pyEphem objects are not used in the functions that I want to parallelize. This is an example file of my code (minimized). This is my main file: main.py import ephem import numpy import math import multiprocessing as mp from SampleSats import Sats