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This paper gives a description of the technique and equipment used to make solar observations in the near IR region with a coronagraph. Examination of active-region spectra in the neighborhood of the He 110830 Å line confirm that the the line is enhanced in sunspot umbrae. The line profiles of umbrae and faculae differ qualitatively. Flares show a decrease in the line depth in comparison to faculae, and in flare kernels the line undergoes an emission reversal. Simultaneous observations of spectra of chromospheric spicules at two heights above the solar surface reveal that the half-width of the 10830 line increases with height.

This work presents the results of measurements of intradome astroclimate parameters of the AZT-14 telescope of Sayan solar observatory of the ISTP SB. The picture of airflows concerned with the warm air run-out though leaky connections and air mixing inside the telescope after dome opening is obtained. It is shown that the value of the structure characteristic of the refractive index C n 2 in closed and open dome can 1.5-2 times differ. Essential turbulence intensification in front of the entrance telescope mirror when dome opening is ascertained. Strongly unstable stratification near the receiver is observable, caused by the stair opening in the concrete floor of the dome, which can result in intensification of the refractive index fluctuations in the presence of even small heat sources. Conclusions are drawn from the measurements, which can be related to all telescope of the considered class. It is necessary to prevent foreign heat sources in the dome and block warmer airflows from the stair opening; astronomical observations are to be carried out after completion of transient processes related to the dome opening.