As you can see, there are no zeros in the bidirectional MTF, the minima are about 7% of the maximum. Thus, we can make a numerical deconvolution to achieve an image equivalent to the one obtained with a single dish telescope.
A compact interferometer like SOLARNET (3 telescopes of Ø350 mm on a 1 meter baseline) is comparable to a single dish telescope in many respects since the Modulation Transfer Function (MTF) covers all the spatial frequencies of the image. The repartition is not excellent for intermediate frequencies since deeps up to 7.3% can be noticed. Nevertheless high frequencies are well represented and a simple deconvolution (or even Wiener filtering) allows to recover totally the image information. The secondary peaks are one third the central peak amplitude which explains the excellent imaging capabilities of the interferometer.
|
MTF of SOLARNET
As you can see, there are no zeros in the bidirectional MTF, the minima are about 7% of the maximum. Thus, we can make a numerical deconvolution to achieve an image equivalent to the one obtained with a single dish telescope. |
Image reconstruction of a complex and extended object with SOLARNET. Note the excellent reconstruction capabilities (both in terms of spatial resolution and intensities) when the phase errors are below 1/6th of the wavelength. This indicates the minimum requirements to achieve with the cophasing system. These images result from the simple deconvolution of a single exposure made with SOLARNET: a SOLARNET 2D-interferogram directly gives a solar image.
 |
 |
Comparaison of SOLARNET with two other instruments : one elementary telescope of SOLARNET, and a telescope of 875 mm diameter.
Simulation on a picture of the SUN for this three telescope when the three beams
are perfectly cophased.