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Hi Hugh, Just a side note. Carefully looking to the blue part of your spectra, the orange line is on top, while it is in the middle in the red part, for example. So I suggest there is tilt of the continuum slope. My first impulse was thinking it should be a problem of color calibration due to differ...

Paolo, ... I have almost no signal below 3700A .... I agree. As posted in another thread: Even above wavelengths of 3800 nm luminosity isn't as bright, as one should expect. Given a B-type companion of the suggested mass ratio of both stars of the binary system should be a hot giant star, which shou...

Paolo, thank you for your thoughts. This points into similar direction, what I was thinking about. Much of the work for interstellar reddening has been done by using integral photometry. It doesn't seem to be easy, however, to use the integral photometric values E(B-V) to obtain a correction in the ...

Phil, Thanks for the hint. I'll wait a little while for alpha Ori. Air mass and seeing could be a mess, however. Looking onto my first raw spectra taken for alpha Lyr with the Alpy, Canon DSLR and Astronomik UV/IR Filter, the setup should go down to 3800 A. But intensities to be expected here are no...

Paolo,

thanks for the work. Good hint to try this using mu Cep.

Weather is cloudy here and waiting for new adapter to use my focal reducer. I'll give it a try with both stars VV and mu Cep with my Alpy.

Thilo

Paolo, this is very interesting to see the UV part in more detail. Having the plots "normalized" to equal width of the uploaded images probably would it make easier to compare spectral portions and wavelength identification of lines of alpha Lyr and VV Cep. Ginestet and Carquillat (2002) s...

Hi Phil, This isn't completely the case. If the source is extended, e.g., nebulosity on the sky, or in the case of spectroscopy, a continuous stellar spectrum, binning *will* improve the S/N when the noise is dominated by photon (Poisson) statistics. Generally, this is the case of incoherent light d...

Robin, This is a really impressive work. What reference star did you use? Flux calibrating the spectra using a reference star can only add information and does not harm the SNR of course as the measurement is only used to determine the shape of the continuum so is heavily filtered. I wouldn't agree ...

Olivier, I totally agree with using the reference star. The contributions 1-4 are all found in one single observation. Usually, I would try to avoid to use a star with a low signal, as this kind of calibration might be crucial to estimate a signal and errors from the spectra. From experience with im...

Hi Ernst, I'm always impressed, how different the numbers taken from simulations of star evolution will appear. However, this ratio of the luminosities is within certain limit of what I also expected to find from independent computations. I roughly estimated 1.5 and 2 magnitudes difference in bright...