We report a multisite photometric campaign for the β Cephei star 12 Lacertae. 750 h of high‐quality differential photoelectric Strömgren, Johnson and Geneva time‐series photometry were obtained with nine telescopes during 190 nights. Our frequency analysis results in the detection of 23 sinusoidal signals in the light curves. Ten of those correspond to independent pulsation modes, and the remainder are combination frequencies. We find some slow aperiodic variability such as that seemingly present in several β Cephei stars. We perform mode identification from our colour photometry, derive the spherical degree ℓ for the five strongest modes unambiguously and provide constraints on ℓ for the weaker modes. We find a mixture of modes of 0 ≤ℓ≤ 4. In particular, we prove that the previously suspected rotationally split triplet within the modes of 12 Lac consists of modes of different ℓ; their equal frequency splitting must thus be accidental. One of the periodic signals we detected in the light curves is argued to be a linearly stable mode excited to visible amplitude by non‐linear mode coupling via a 2:1 resonance. We also find a low‐frequency signal in the light variations whose physical nature is unclear; it could be a parent or daughter mode resonantly coupled. The remaining combination frequencies are consistent with simple light‐curve distortions. The range of excited pulsation frequencies of 12 Lac may be sufficiently large that it cannot be reproduced by standard models. We suspect that the star has a larger metal abundance in the pulsational driving zone, a hypothesis also capable of explaining the presence of β Cephei stars in the Large Magellanic Cloud.

We report on the second multisite photometric campaign devoted to ν Eridani (ν Eri). The campaign, carried out from 2003 September 11 to 2004 February 16, was very nearly a replica of the first campaign, 2002–2003: the five telescopes and photometers we used were the same as those in the first campaign, the comparison stars and observing procedure were identical, and the numbers and time baselines of the data were comparable. For ν Eri, analysis of the new data adds four independent frequencies to the nine derived previously from the 2002–2003 data: three in the range 7.20–7.93 d−1 and a low one, equal to 0.614 d−1. Combining the new and the old data results in two further independent frequencies, equal to 6.7322 and 6.2236 d−1. Altogether, the oscillation spectrum is shown to consist of 12 high and two low frequencies. The latter have u amplitudes about twice as large as the v and y amplitudes, a signature of high radial‐order g modes. Thus, we confirm the suggestion, put forward on the basis of the data of the first campaign, that ν Eri is both a β Cephei and a slowly pulsating B (SPB) star. Nine of the 12 high frequencies form three triplets, of which two are new. The triplets represent rotationally split ℓ= 1 modes, although in case of the smallest‐amplitude one this may be questioned. Mean separations and asymmetries of the triplets are derived with accuracy sufficient for meaningful comparison with models. The first comparison star, μ Eri, is shown to be an SPB variable with an oscillation spectrum consisting of six frequencies, three of which are equidistant in period. The star is also found to be an eclipsing variable. The eclipse is a transit, probably total, the secondary is fainter than the primary by several magnitudes, and the system is widely detached. The second comparison star, ξ Eri, is confirmed to be a δ Scuti variable. To the frequency of 10.8742 d−1 seen already in the data of the first campaign, another, equal to 17.2524 d−1, is added.

We undertook a multisite photometric campaign for the β Cephei star ν Eridani. More than 600 h of differential photoelectric uvyV photometry were obtained with 11 telescopes during 148 clear nights.The frequency analysis of our measurements shows that the variability of ν Eri can be decomposed into 23 sinusoidal components, eight of which correspond to independent pulsation frequencies between 5 and 8 cd −1 . Some of these are arranged in multiplets, which suggests rotational m-mode splitting of non-radial pulsation modes as the cause. If so, the rotation period of the star must be between 30 and 60 d.One of the signals in the light curves of ν Eri has a very low frequency of 0.432 cd −1 . It can be a high-order combination frequency or, more likely, an independent pulsation mode. In the latter case, ν Eri would be both a β Cephei star and a slowly pulsating B (SPB) star.The photometric amplitudes of the individual pulsation modes of ν Eri appear to have increased by about 20 per cent over the last 40 years. So have the amplitudes of the dominant combination frequencies of the star. Among the latter, we could only identify sum frequencies with certainty, not difference frequencies, which suggests that neither light-curve distortion in its simplest form nor resonant mode coupling is their single cause.One of our comparison stars, µ Eridani, turned out to be variable with a dominant time-scale of 1.62 d. We believe either that it is an SPB star just leaving its instability strip or that its variations are of rotational origin.

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Kepler is a new NASA space mission that is scheduled for the launch in February 2009. We describe Kepler's scientific goals and the asteroseismic part of its investigation. Then, we present our program of ground-based spectroscopic and photometric observations of Kepler asteroseismic targets and we show results obtained by us in the first two years of its realization.

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