[AstroPy] Compute approximate WCS for a given wide-field photo

[John K. Parejko]

http://astrometry.net/

You can use the web interface, or download the package and run it locally.

You don’t even need to know the field location by hand: it’s pretty good at figuring it out, so long as there are a reasonable number of stars.

John

> On 12Nov 2017, at 08:52, Christoph Deil <deil.christoph at googlemail.com> wrote:
> 
> Hi,
> 
> I’d like to make some images that combine a normal photo with an astronomical survey image, as in this example:
> https://de.wikipedia.org/wiki/High_Energy_Stereoscopic_System#/media/File:HESS-Gammastrahlungsquellen_Montage.jpg
> 
> I know about http://reproject.readthedocs.io, but to use it I need a WCS for the photo.
> 
> Let’s assume I know the sky position of a few pixels in the photo already (from star finding or by hand).
> 
> How can I get an approximate WCS for the photo?
> 
> Is there some projection that roughly matches what wide-field (non-astronomical, hand-held, covering ~ 50 deg on the sky) photo cameras do?
> I presume the projection reference point should always be at the centre of the image?
> Can the pixel scale parameters can be computed from EXIF meta information in the photo?
> 
> Is there a good web page with a description, or even a Python package that will help me compute the WCS?
> 
> Or is the whole approach of trying to go via a WCS transform for the photo not a great idea, and some other transform should be used?
> 
> Any tips would be appreciated!
> 
> — Christoph
> 
> _______________________________________________
> AstroPy mailing list
> AstroPy at python.org
> https://mail.python.org/mailman/listinfo/astropy