# Constructing a WCS from camera geometry

**URL:** <https://www.rubin.community/t/constructing-a-wcs-from-camera-geometry/3039>\
**Category:** DM Notifications\
**Tags:** dm-dev\
**Created:** [July 11, 2018, 11:24pm UTC](https://www.rubin.community/t/constructing-a-wcs-from-camera-geometry/3039 "2018-07-11T23:24:25Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![rowen](https://sea2.discourse-cdn.com/flex002/user_avatar/www.rubin.community/rowen/32/52_2.png) [@rowen](https://www.rubin.community/u/rowen)\
**Post date:** [July 11, 2018, 11:24pm UTC](https://www.rubin.community/t/constructing-a-wcs-from-camera-geometry/3039/1 "2018-07-11T23:24:25Z")

</div>

As of [DM-14932](https://jira.lsstcorp.org/browse/DM-14932) it is now possible to construct a celestial WCS from camera geometry and the telescope pointing. The new function is

```
makeSkyWcs(pixelsToFieldAngle, orientation, flipX, boresight, projection="TAN")

```

The resulting WCS will have a CRVAL equal to `boresight` and a CRPIX at the center of the focal plane (thus well off most CCDs in a mosaic camera). The orientation is of the focal plane, not detector pixels, which has the benefit that you can use the same value of `orientation` for all detectors, even if some detectors are rotated with respect to others (e.g. HSC). See the source code documentation for details.