ASTRONIRCAM is a cryogenic-cooled slit camera-spectrograph for the spectral range 1–2.5 μ m installed at the Nasmyth focus of the 2.5-meter telescope of the Caucasian observatory of the Sternberg Astronomical Institute of Lomonosov Moscow State University. The instrument is equipped with a HAWAII-2RG 2048×2048 HgCdTe array. Grisms are used as dispersive elements. In the photometric mode ASTRONIRCAM allows for extended astronomical object imaging in a 4.′6 × 4.′6 field of view with a 0.269 arcsec/pixel scale in standard photometric bands J , H , K , and K s as well as in the narrow-band filters centered on the lines CH 4 , [Fe II], H 2 v=1-0 S(1), Br γ , and CO. In the spectroscopic mode, ASTRONIRCAM takes spectra of extended or point-like sources with a spectral resolution of R = λ /Δ λ ≤ 1200. The general design, optical system, detector electronics and readout, amplification and digitization schemes are considered. The GAIN conversion factor measurement results are described as well as its dependence on the accumulated signal (nonlinearity). The full transmission of the atmosphere-to-detector train ranges from 40 to 50% in the wide-band photometry mode. The ASTRONIRCAMsensitivity at the 2.5-m telescope is characterized by the limiting J = 20, K = 19 stellar magnitudes measured with a 10% precision and 15 minute integration for 1″ atmospheric seeing conditions. References to the first results based on ASTRONIRCAM observations are given.

Photometric data in the JHKLM near infrared bands obtained in 1999-2000 are presented for the long-period eclipsing system ε Aur. The time of secondary eclipse (when the F21 supergiant eclipses a dust disk surrounding the more massive component of the system) is calculated using the latest orbital elements of the system. A brightness minimum with an amplitude of ~0m.05 is observed in all bands at the phase of the expected secondary eclipse (φ = 0.606). The nearest subsequent time of a secondary eclipse, which will occur in December 2026-February 2027, is calculated. It is shown that during the secondary minimum the B5V star currently proposed as the secondary component cannot be eclipsed. It is proposed that the eclipsed component should be a hot star surrounded by a gas-dust cloud and with luminosity and radius exceeding the typical values for Main sequence stars.

We present the results of our long-term (»13 years) J and K photometry of the X-ray binary Cyg X-1. The object’s JK variability amplitudes were less than 0: 2. The J and K orbital light curves are appreciably asymmetric in quadratures. The secondary minimum is deeper, in comparison to the primary, and it is probable that the star becomes hotter at secondary minima. The ratio of average radii of the supergiant in quadratures and in minima is »1.02 if the temperature of the optical component does not change during its orbital motion. We estimate the interstellar extinction as E(B iV ) = 1: 025§0: m 006 and the distance to the star, as d = (2:44§0:04) kpc. The luminosity and radius of the optical component are respectively » 2:8 ¢ 10 5 Lfl and 21 Rfl. The JK variations of the X-ray binary Cyg X-1 in 1995{2007 can be explained with orbital ellipsoidal variations of the optical component (hot supergiant HD 226868), accompanied with long-term JK variations on a time scale of 11.5 years with an amplitude of 0: 06{0: m 07. In 1995{2007, the JK brightness ∞uctuations probably had a 294-day periodicity with an amplitude of no more than 0: 03{0: m 05.

Since 1994, observations of a sample of about 20 Mira Ceti-type and semiregular variables have been carried out in three spectral ranges: radio (H2O maser line λ = 1.35 cm), optical (spectroscopy and UBV photometry) and infrared (JHKLM photometry). Time series of the Hα emission intensity and H2O line flux, covering several periods of the stars, have been obtained. Correlation of the intensity variations of the H2O maser with optical variability in the maser stars RR Aql, U Ori, VX Sgr and others was confirmed. One of the most interesting results is the flare of the H2O maser emission in R Leo, which happened in autumn 1997, 14 months after a flare of the Hα emission.

The error circles of ten X-ray sources are investigated at optical and infrared wavelengths using Palomar sky survey plates, and deep photographic survey plates obtained with the UK Schmidt telescope at the Anglo-Australian observatory. The objects were cross-identified with the catalogs of variable stars, IRAS point sources and Einstein of X-ray sources in the same sky region.As expected, very strong interstellar dust absorption is typical for all the X-ray source fields.Variable star No 2547 from the list by Terzan and Gosset (1992) was found to be located near the southern boundary of the KS 1731-260 error circle. The star is identified with the source IRAS.17311-2604, and varies from 16(m) to fainter than 20(m) on our r-band plates.IRAS 17342-2908 and another infrared source 358.83+1.39 discovered by Kawara et al. (1983) at 2.21 mu m are located near the error box of GRS 1734-292. We have found an optical counterpart for these infrared sources, the star is very red and bright in the near infrared with no signs of high amplitude light variations. It may be a highly reddened OB-star. As in the previous case, the positions of IRAS 17342-2908 and infrared source 358.83+139, were found to coincide with a red star also bright in the near infrared and al these objects are covered by the error circle of GRS 1736-297.The error circle of KS 1741-293 is covered by both error boxes of IRAS 17417-2919 and of FIR 5, a far infrared source discovered earlier by Odenwald and Fazio (1984) at 40-250m wavelength band. The latter object is known to be extended with the diameter of 2.'7 +/- 0.'6 and coincides with the radio source G 359.54-068 also known to be extended with the diameter of 2'90. No trace of an optical counterpart to this object is seen on optical and near infrared plates, and there are no highly reddened star in the error box.The center of highly reddened globular cluster Terzan 6 is located on the south-western boundary of the 95 arcsecond diameter error circle of GRS 1747-312. On the deep infrared UKST plates the cluster is seen to extend inside the error circle. So this may be another association of a globular cluster with an X-ray source.Optical photographic reproductions of error circles and their neighborhood are presented, some stars with outstanding blue or red colors are marked.