We describe the present status of the mass discrepancy in the Upper HR Diagram.

We explore whether medium-resolution stellar spectra can be reconstructed from photometric observations, taking advantage of the highly compressible nature of the spectra. We formulate the spectral reconstruction as a least-squares problem with a sparsity constraint. In our test case using data from the Sloan Digital Sky Survey, only three

We present optical spectra with high signal-to-noise ratio of 10 BL Lac objects detected at GeV energies by the Fermi satellite (3FGL catalog), which previous observations suggested are at relatively high redshift. The new observations, obtained at the 10 m Gran Telescopio Canarias, allowed us to find the redshift for J0814.5+2943 (z = 0.703), and

HD 168625 (B9-A0 Ia) was classified as a post-AGB star and also as a luminous blue variable. We have analysed the high resolution optical spectra of HD 168625 and derived the atmospheric parameters and the chemical composition. We obtained Teff = 15000K, log g = 2.5, xit = 6km/s and [M/H] = 0.0, and estimated the chemical composition. We find [C/H]

In the high resolution optical spectra we identified forbidden lines of [OI] and [CI], which indicate the presence of low excitation nebula. There are many emission lines due forbidden and permitted lines of neutral and singly ionised metals. The Hα, FeII 6383Å, NaI D1, D2 lines and the CaII IR triplet lines show P-Cygni profiles indicating a mass

HD 331319 is a F3 Ib star with a detached cold circumstellar dust shell with far-IR colours similar to planetary nebulae. From an analysis of high resolution spectra using LTE stellar atmospheric models, we have derived the atmospheric parameters and the chemical composition of HD 331319. By matching the theoretical and the observed spectrum we