WFPC2 1-Gyro Test Results. Matt McMaster Marco Sirianni. The Test. Program 11077 was initially designed for ACS/HRC using the TGM original program test as a template. 11077 was converted to WFPC2/PC by Matt McMaster maintaining an observational strategy very close to the original.
WFPC2 1-Gyro Test Results
PSF FWHM distribution
(unit: PC pixel -all data included)
Mean: 1.67 pix ± 0.16
Mean: 1.65 pix ± 0.14
The average PSF FWHM is remarkably similar indicating no obvious
degradation inperformance in 1-Gyro mode
As done for the TGM test, the dependence of the FWHM
on exposure time, guide star brightness, and position on
the sky was analyzed:
There is no difference between images taken with a V=13 and V=14 guide star
There are small differences in the PSF width due to the exposure time duration.
Data from NGC 6341 only
2 – GYRO
10 sec 1.66 ± 0.03
100 sec 1.70 ± 0.03
400 sec 1.85 ± 0.04
1 – GYRO
10 sec 1.63 ± 0.02
100 sec 1.70 ± 0.04
400 sec 1.82 ± 0.05
Such differences were also noted during the original 2-Gyro on orbit verification test with the ACS/HRC.
The average PSF width in NGC 5904 data is systematically smaller than in NGC 6341, but there is no dependency on the gyro guiding configuration.
A similar result was found for the clusters observed in the original 2-gyro on-orbit test with HRC
NGC 6341 /PC
F555W -100 sec
There is no evidence that
the quality of the science
data obtained in 1-gyro
mode is any worse than
in 2-gyro mode.