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Asteroseismology of stars in clusters has been a long-sought goal because the assumption of a common age, distance and initial chemical composition allows strong tests of the theory of stellar evolution. We report results from the first 34 days of science data from the Kepler Mission for the open cluster NGC 6819 -one of four clusters in the field of view. We obtain the first clear detections of solar-like oscillations in the cluster red giants and are able to measure the large frequency separation, ∆ν, and the frequency of maximum oscillation power, ν max . We find that the asteroseismic parameters allow us to test cluster-membership of the stars, and even with the limited seismic data in hand, we can already identify four possible non-members despite their having a better than 80% membership probability from radial velocity measurements. We are also able to determine the oscillation amplitudes for stars that span about two orders of magnitude in luminosity and find good agreement with the prediction that oscillation amplitudes scale as the luminosity to the power of 0.7. These early results demonstrate the unique potential of asteroseismology of the stellar clusters observed by Kepler.

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CCD UBVRi photometry of the final helium flash object V4334 Sgr (Sakurai's Object), carried out during 1997 -1999, is presented, and the light curve from its pre-discovery rise to the dust obscuration phase is constructed. The optical light curve can be divided into four sections, the rise to maximum, the maximum, the dust onset, and the massive dust shell phase. The color indices show a general increase with time, first because of the photospheric expansion and cooling, and later because of the dust forming events. The energy distributions for the years 1996 -1999 show that an increasing part of the energy is radiated at infrared wavelengths. In 1996, the infrared excess is likely caused by free-free radiation in the stellar wind. Starting from 1997 or 1998 at the latest, carbon dust grains are responsible for the more and more dramatic decrease of optical radiation and the growing infrared excess. Its photometric behavior in 1998 -1999 mimics the "red declines" of R CrB variables, the amplitude, however, is more extreme than any fading ever observed in an R CrB star. Evidence is given that a complete dust shell has formed around V4334 Sgr. It therefore shows similarities with dust-forming classical novae, although evolving ∼ 20 times more slowly. Its luminosity increased by a factor 4 between 1996 and 1998. A comparison of time scales of the final helium flash objects FG Sge, V605 Aql and V4334 Sgr shows that the observed photometric and spectroscopic features are similar, while V4334 Sgr is the most rapidly evolving object to date. ObservationsUBVRi observations of V4334 Sgr were carried out with the 0.91 m Dutch light collector at ESO La Silla, until its shutdown on April 1, 1999. Filters and comparison stars were the same as those used in D97 (the filters R and i refer to Cousins R C and Gunn i G , respectively). The object was also observed until 1998 October with the 0.2 m f /1.5 Schmidt telescope of W. Liller in Reñaca, Viña del Mar, Chile. Additional observations were obtained with the 3.5 m Telescopio Nazionale Galileo (TNG) 6 in July, 1999.The early observations with the Dutch telescope were analyzed using ROMAFOT aperture photometry. The continuing decline in brightness, especially at short wavelengths, made it necessary to carry out DAOPHOT profile fitting photometry of V4334 Sgr from 1997 September 15 onward. Because of the increase of exposure times, comparison star (1) of D97 became too bright to be used as a local standard, and the average magnitude of stars (2) − (6) (taken from D97) was used as the reference magnitude in all filters. The Reñaca observations are based on CCD aperture photometry. Since they were always taken relative to star (1) through a non-standard V filter which extends towards the red, a transformation was established from simultaneous Dutch (V, i) and Reñaca (∆V ⋆ ) observations, which permits to convert the Reñaca observations into the standard V system:where ∆V ⋆ is the magnitude difference relative to the bright comparison star; the color V − i is taken from the "Dutch" ...

Measuring solar‐like oscillations in an ensemble of stars in a cluster, holds promise for testing stellar structure and evolution more stringently than just fitting parameters to single field stars. The most‐ambitious attempt to pursue these prospects was by Gilliland et al. who targeted 11 turn‐off stars in the open cluster M67 (NGC 2682), but the oscillation amplitudes were too small (<20 μmag) to obtain unambiguous detections. Like Gilliland et al. we also aim at detecting solar‐like oscillations in M67, but we target red giant stars with expected amplitudes in the range 50–500 μmag and periods of 1 to 8 h. We analyse our recently published photometry measurements, obtained during a six‐week multisite campaign using nine telescopes around the world. The observations are compared with simulations and with estimated properties of the stellar oscillations. Noise levels in the Fourier spectra as low as 27 μmag are obtained for single sites, while the combined data reach 19 μmag, making this the best photometric time series of an ensemble of red giant stars. These data enable us to make the first test of the scaling relations (used to estimate frequency and amplitude) with an homogeneous ensemble of stars. The detected excess power is consistent with the expected signal from stellar oscillations, both in terms of its frequency range and amplitude. However, our results are limited by apparent high levels of non‐white noise, which cannot be clearly separated from the stellar signal.