The Velocity And Magnetic Observations of the Sun (VAMOS), operative at the INAF–Osservatorio Astronomico di Capodimonte, is a narrow-band filter based on the MOF technology. VAMOS is capable of acquiring intensity, velocity, and magnetic field full-disk images in the K I D1 line at 7699 Å with video cadence and medium spatial resolution (http://vamos.na.astro.it). This instrument was so far used to study the solar photospheric dynamics (the five minute oscillations and their background) by means of the phase difference between the intensity and velocity fluctuations. However, it is clearly suitable for studying magnetic oscillations in solar active regions thanks to the nearly simultaneous acquisition of velocity and magnetic field images. Moreover, the VAMOS data can be useful for the space weather study and help in the forecasting events such flares and coronal mass ejection. In fact, Doppler and magnetic observations can be used to monitoring the solar activity cycle and, with data from other instruments, to study the correlations between solar dynamic and magnetic activity at different hights in the solar atmosphere.
Samples of intensity, Doppler and magnetic full-disk images acquired by VAMOS are shown in the three figures at left. A preliminary calibration of the magnetogram in the figure sample indicates the right polarity and the maximum negative and positive polarities corresponding to about −400 Gauss and +300 Gauss respectively. The quality of these rough images is very satisfactory and such as to fully support a further investment for building a version of the VAMOS instrument having a spatial resolution better than the present one, which is limited to 12 arcsec corresponding to the diffraction limit of the VAMOS lens at 7699 Å. We plan to change the optical system and to upgrade the CCD camera in order to get a spatial resolution of 0.5 arcsec for fulldisk solar images.
Simultaneously with VAMOS data, we can already acquire high resolution full-disk images in white light and Hα filter, at 0.5”/pixels (figures below).
Contact person: Maurizio Oliviero