[AstroPy] Proper Motions in astropy.coordinates

[Josh Walawender]

Glad to hear it.  I would encourage support for handling uncertainties in both the initial position, the proper motion values, and the uncertainty in the calculated position.  This would have been valuable to me in planning a recent observing run.  I did some calculations for that run using the small angle approximation.  I need to upgrade those to use proper spherical geometry.  I may play around with doing my own subclassing of SkyCoord to add this.  If I come up with something useful I’ll post it.

cheers,
Josh




On May 12, 2015 at 6:57:29 AM, Adrian Price-Whelan (adrianmpw at gmail.com) wrote:

Right now, there is no proper motion or velocity support in Astropy,  
but this is going to be the next major feature push for the  
coordinates subpackage.  

Thanks,  
Adrian  

On Mon, May 11, 2015 at 11:49 PM, gonghang.naoc <ghang.naoc at gmail.com> wrote:  
> I have a similar question. Is there any other package about PM calculation?  
> Thank you.  
> Hang  
>  
> On Sun, May 10, 2015 at 5:24 PM, Josh Walawender <jmwalawender at gmail.com>  
> wrote:  
>>  
>> Hi all,  
>>  
>> Is there a method do calculations of proper motions in  
>> astropy.coordinates? It looks to me as if the SkyCoord has obstime and  
>> equinox properties but how would I transform from a coordinate defined for a  
>> particular obstime and equinox to another obstime (e.g. for the same  
>> equinox)?  
>>  
>> I just did this calculation in a brute force way (multiplying the proper  
>> motion in mas/yr by number of years and adding that angle to the ra and dec  
>> independently), but it felt like there should be a better way.  
>>  
>> thanks!  
>> Josh  
>>  
>>  
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--  
Adrian M. Price-Whelan ~ Columbia University ~ http://adrian.pw  
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