Reference Coordinates in Fixed Projections

SkyView treats a number of projections (Aitoff, Cartesian, Sansom-Flamsteed/Sinusoidal) as fixed projections. Regardless of the position you specify, the sky is projected to the plane in the same way. All that your coordinate entry changes is the center of the image you get. Thus if you ask for an image near the pole in a Cartesian projection, you’ll find that there’s a large distortion since you are near a singularity in the projection. By contrast, projections like the Tangent and Sine projections are centered at the position you specify: that’s the point of minimum distortion.

If you wanted to make an Aitoff or Cartesian map really centered on some point other than the coordinate origin, older versions of SkyView couldn’t help you. With the version we’re releasing today, you can specify the new RefCoords setting. It takes a pair of decimal coordinates and uses that as the coordinate center for fixed projections. E.g., use RefCoords=0.,90. Position=0.,90. projection=Ait to ask for an Aitoff projection centered around the pole. Note that you still need to specify a position.

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