LSST Applications  21.0.0-172-gfb10e10a+18fedfabac,22.0.0+297cba6710,22.0.0+80564b0ff1,22.0.0+8d77f4f51a,22.0.0+a28f4c53b1,22.0.0+dcf3732eb2,22.0.1-1-g7d6de66+2a20fdde0d,22.0.1-1-g8e32f31+297cba6710,22.0.1-1-geca5380+7fa3b7d9b6,22.0.1-12-g44dc1dc+2a20fdde0d,22.0.1-15-g6a90155+515f58c32b,22.0.1-16-g9282f48+790f5f2caa,22.0.1-2-g92698f7+dcf3732eb2,22.0.1-2-ga9b0f51+7fa3b7d9b6,22.0.1-2-gd1925c9+bf4f0e694f,22.0.1-24-g1ad7a390+a9625a72a8,22.0.1-25-g5bf6245+3ad8ecd50b,22.0.1-25-gb120d7b+8b5510f75f,22.0.1-27-g97737f7+2a20fdde0d,22.0.1-32-gf62ce7b1+aa4237961e,22.0.1-4-g0b3f228+2a20fdde0d,22.0.1-4-g243d05b+871c1b8305,22.0.1-4-g3a563be+32dcf1063f,22.0.1-4-g44f2e3d+9e4ab0f4fa,22.0.1-42-gca6935d93+ba5e5ca3eb,22.0.1-5-g15c806e+85460ae5f3,22.0.1-5-g58711c4+611d128589,22.0.1-5-g75bb458+99c117b92f,22.0.1-6-g1c63a23+7fa3b7d9b6,22.0.1-6-g50866e6+84ff5a128b,22.0.1-6-g8d3140d+720564cf76,22.0.1-6-gd805d02+cc5644f571,22.0.1-8-ge5750ce+85460ae5f3,master-g6e05de7fdc+babf819c66,master-g99da0e417a+8d77f4f51a,w.2021.48
LSST Data Management Base Package
lsst::obs::test; Simple camera and data repository for testing

obs_test models a simple camera with one CCD and includes a data repository containing a few raw images and some associated calibration data.

obs_test is designed to be used for unit tests that require camera geometry and/or a small data repository.


The obs_test camera consists of a single CCD whose geometry matches a subregion of a single LSST CCD. The chosen LSST CCD is is near, but not at, the center of the LSST focal plane, in order to make the obs_test camera geometry nontrivial and to provide a bit of distortion. A subregion is used (rather than simply using an entire LSST CCD) in order to make the images smaller.

In detail, the obs_test CCD, sensor 0, corresponds to the following LSST CCD subregion:

  • Raft R2,2 (the center raft)
  • CCD/sensor S0,0 (the lower left CCD in the raft)
  • Amplifiers/channels C0,0, C0,1, C1,0 C1,1, keeping only the 1000 pixels in Y nearest the center line of the CCD

obs_test CCD amplifiers map as follows to LSST CCD amplifiers:

  • "00" = "C0,0"
  • "10" = "C0,1"
  • "01" = "C1,0"
  • "11" = "C1,1"

The data ID keys that may be used to identify "raw" images and (except for "amp") "calexp" images are:

  • amp: amplifier name: one of "00", "01", "10", "11" (not used for calexp)
  • ccd: ccd number: always 0
  • filter: filter name
  • visit: exposure number

Like the LSST camera, the obs_test camera focal plane coordinates are rotated 90 degrees from pixel coordinates. (The focal plane coordinates are determined by the camera engineers, whereas CCD pixel coordinates are required to have x along rows and y along columns).


The data directory includes the following:

  • a file describing the data and how it was generated
  • input: the data repository. This includes three raw images and associated flats, biases and defects.
  • utils: scripts used to generate the data from lsstSim data

Unlike the LSST camera, but like most other cameras, obs_test raw images combine the data from all amplifiers into a single image.


Useful classes include:

  • TestCamera: camera geometry for the obs_test camera. Unlike most obs_* packages this package builds its own camera geometry (by instantiating this class), rather than relying on the lsst.obs.base.CameraMapper to load camera geometry data from a persisted lsst.afw.cameraGeom.CameraConfig.
  • TestMapper: camera mapper for the obs_test camera


To obtain the camera geometry and a raw image:

import os.path
import lsst.utils
obsTestDir = lsst.utils.getPackageDir('obs_test')
input = os.path.join(obsTestDir, "data", "input")
butler = lsst.daf.persistence.Butler(root = input) # don't add to the input repo
rawImage = butler.get("raw", dict(visit=1))
cameraGeom = butler.get("camera")
std::ostream * os
A base class for image defects.