Аннотация
Initially the object M1-15 was included in the Catalogue of Galactic Planetary Nebulae by Perek & Kohoutek (1967), later it was classified as a Be star by Sanduleak & Stephenson (1973) and received a new designation: SS73 6. Shaw & Kaler (1989) discovered some high excitation lines of He II, 4686 Å, [OIII], 5007 Å, [NII], 6583 Å in its spectrum and suspected that this could be a symbiotic star.However later only HI, [OI] and [NII] lines were observed in the spectrum of M1-15, and no trace of a cool component was detected.All available photometric data for this object are compiled in Table 1.Our observations were carried out in 2012 with the 1-meter Carl-Zeiss Jena reflector, located at Assy-Turgen Observatory of Fesenkov Astrophysical Institute (FAPHI).It was equipped with the CCD camera SBIG ST-7 (765 × 510, 9µ) and samples of BV R filters.HD 69901 and HD 71099 were used as standards.Increase of brightness of M1-15 by 0. m 2 in all filters was registered during 1984-2012.The main volume of spectral data was obtained with the original slit spectrograph, attached to the 0.7-m Cassegrain reflector AZT-8, located at Observatory of FAPHI.In 1971-1995 the spectrograph was equipped with the three-cascade image-tube, and the special astronomical film was used as a detector.A sample of gratings and objective lenses provided a spectral range from 3700 to 8200 Å.Since 2005 the spectrograph has been equipped with the CCD camera SBIG ST-8 (1530 × 1210, 9µ) with available spectral range 4000-7500 Å.The entrance slit width equals to 3 ′′ -4 ′′ and 10 ′′ -15 ′′ .Spectrograms, obtained with the broad slit are used for emission fluxes and EW determination, and those, with narrow slit for the study of emission profiles.Some spectra of M1-15 were obtained with a Shelyak eShel spectrograph and a slit spectrograph, attached to the 1meter Carl-Zeiss Jena reflector (Tyan-Shan Observatory of FAPHI).Table 2 gives the log of observations.All spectrograms were corrected for atmospheric extinction.There are emission lines of HI, [OI] and [NII], 6583 Å in the spectrum of M1-15.The object is observed on a background of an HII region, and an appropriate extended Hα emission is present on our spectrograms, obtained with the maximal expose time.This line together with the sky spectrum was measured on both sides of the stellar continuum and was subtracted from the observable spectrum of the object.The absolute fluxes and equivalent widths for the Hα and Hβ are listed in Table 3.It is noticeable that the flux of Hα increased more than twice up to 2010-2013 and then began to decrease.Behaviour of the F(Hβ) and EW values is quite similar.