<Insert general project description>

HOWTO
=====

Obtain the HIP database
-----------------------

1. Download hip_main.dat from ftp://cdsarc.u-strasbg.fr/pub/cats/I/239.
2. Place hip_main.dat into data/.


Calibrate a camera from a star field image
------------------------------------------

1. Identify stars names (as labelled in Hipparcos catalogue), and their pixel
   coordinates. Stellarium can be used to find star names. An image editor (eg.
   GIMP) can be used to find pixel coordinates. Five stars from the edge of the
   image and five nearer the center should give an accurate calibration.
2. Update the dict at the bottom of calibrate_from_stars.py accordingly.
3. Run ./calibrate_from_stars.
4. Update CAMERAS with the obtained pixel scale and barrel distortion
    parameter.


Find camera orientation from a star field image
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This requires the camera to have already been calibrated (see above).

1. Use SExtractor to obtain a catalogue of stars from your image. SExtractor
    requires a FITS image as input.

2. Run astdb:

    ./astdb.py -i <input image> -o <output image> -c <cat file> -p <ps> -b <bd>

    <input image> is the star field being orientated. It should be the same
    star field that was passed to SExtractor, although it should be in a format
    that OpenCV can read (eg. JPEG).

    <output image> will be a copy of input image, annotated with fitted star
    labels.

    <cat file> is the catalogue file produced by step 1.

    <ps> and <bd> are the calibration parameters of the camera used to obtain
    the star field.