Sunday, January 23, 2011

EOS 5D2 Sensor Performance

ISO 1600: gain = 3.34 ADU/e-, readout noise = 2.52 e-

Gain measured with flat fields of various exposure times, assuming Poisson noise. The measured noise distributions are compared with simulations, and are indeed very close to Poisson distribution.

noise-equivalent dark at 20 deg C: 0.80 e-/sec
noise-equivalent dark at 3 deg C: 0.057 e-/sec

Dark measured with series of 10-min exposures and intervals of 10 sec. Temperature is ambient.

Linearity good to a few % when number of electrons is lower than ~6000.

Monday, January 17, 2011

TOA150 with TC14A

Camera: Canon 5D2
Telescope: TAK TOA150 with 67 flattener, with and without Nikon TC 14A 1.4x extender

Result:
Without TC14A, star FWHM is about 2.5 pixels.
With TC14A, it becomes 3.5-4 pixels.

The angular resolution with and without TC14A is quite comparable. There is a hint that it is slightly better without TC14A but that can easily be attributed to difference in weather condition.

On the other hand, there is clear lateral color when TC14A is used and weak astigmatism.

To conclude, the advantage of using TC14A is unproven.