Open Access
Technical Article

Fig. 2

image

Download original image

Radial mapping of the camera, relating the camera-bound colatitude δc of a sky object, and its projected radial distance r on the camera image, measured in pixels. In the case of stars (red diamonds) the measured radial distance comes with the discretization error bar of size (see Appendix B) more visible on the lower panel. The black dots show a simple equidistant mapping rδc . The magenta dashes show the equisolid projection of equation (5b) expected for the fisheye and focal reducer lenses used here; the green solid line show the best fit distorted radial model of equation (5a); while the blue dotted-dashed line illustrate the impact of atmospheric refraction on observations with a perfect equisolid optical system (see Appendix A). The upper panel shows the raw radial distance r, while the lower panel shows the difference between r and the equisolid model.

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.