[amsat-bb] Using JPL Horizons Ephemerides Data

[Zach Leffke]

Not an expert on this so will keep it short:

We had a student at VT look into this for tracking 'Deep Space' objects. 
  He figured out how to access the Horizons website via one of their 
API's (not sure which) and then figured out how to 'shoehorn' the data 
into python scripts that used the 'pyephem' package.

pyephem has been deprecated and replaced by 'SkyField' and is wayyy more 
powerful and has support for things like an SGP4 propagator for 
satellite tracking, and support for tracking astronomical objects (our 
moon/sun for EME'rs on the list and for future Amateur Radio on the 
Lunar Gateway, Jupiter+moons, other radio astronomy sources, etc....). I 
think even directly supports this kind of thing through a 'jplephem' 
package (where it gets the ephemeride data for planets, moons, etc...). 
So might be as easy as download from Horizons (if not directly 
accessible in skyfield), load into skyfield.....yadda yadda yadda 
(seinfeld reference)......get pointing/doppler data for deep space objects.

Bottom line, for those interested in custom software, should look into 
'skyfield' to maybe work with this type of data in python (along with 
TLE data) and there's probably a way to 'export' the ephemerides into 
TLE format so that the results can be used to 'spoof' existing tracking 
programs (technically, SGP4+TLEs are only valid for 'near earth' 
tracking, not even the right algorithm for Lunar/Solar tracking, that's 
why I say 'spoof').

https://rhodesmill.org/skyfield/

-Zach, KJ4QLP

Research Associate
Aerospace Systems Lab
Ted & Karyn Hume Center for National Security & Technology
Virginia Polytechnic Institute & State University
Work Phone: 540-231-4174
Cell Phone: 540-808-6305

On 7/26/2019 11:53 AM, Reid Crowe via AMSAT-BB wrote:
> Looks like someone is already on it:
> https://twitter.com/coastal8049/status/1154760899522994177
> 
> 73,
> 
> Reid N0RC
> 
> On Fri, Jul 26, 2019 at 10:43 AM Reid Crowe <reid.crowe at gmail.com> wrote:
>>
>> Is there a way to use (or convert) JPL Horizons Ephemerides data with
>> tracking programs like SatPC32 that use Two Line Elements?
>>
>> 73,
>>
>> Reid N0RC
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