Version 2 (modified by admin, 4 years ago) (diff) |
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4/8 Point Test
This test measures the basic azimuth and elevation offsets of the structure. The basic idea is to run tracks that are horizontal or vertical where the majority of the correction will be in azimuth or elevation. These corrections are then applied to the structure and the test may be run again to refine the corrections.
4 Point Test
Run trajectories at the cardinal points. Select objects that are close to the center of the tracker for best results. The cardinal points are
Azimuth | Dec | |
0.000 | 65.626 | north trajectory |
65.452 | 38.530 | east trajectory |
180.000 | -4.263 | south trajectory |
294.458 | 38.478 | west trajectory |
Record the actual true azimuth of the structure and the Ra/Dec offsets required to get the object to the center of the field.
The north and south trajectories should require close to the same offset as should the east and west trajectories. The north/south Ra correction should be similar to the east/west Dec correction and it should be applied to the azimuth correction , while the north/south Dec should be similar to the east/west Ra and is applied to the elevation correction.
The correction should be applied with reversed sign to the AOFF and EOFF values in the source file <trunk>/legacy/etc/structureModel.dat. This file should then be installed and the legacyServer restarted to pick up the change. The values may be changed temporarily in the file /opt/het/hetdex/etc/conf/structureModel.dat, however, you will need to use sudo to override the read only file permission.
8 Point Test
Basically the same as the 4 Point test but with more points. Do a test also at the intermediate points as given in the table below.
Azimuth | Dec | |
24.059 | 60.236 | |
125.414 | 7.632 | |
234.586 | 7.632 | |
335.941 | 60.236 |