HR 6819, also known as HD 167128 or QV Telescopii (abbreviated QV Tel), is a double star system in the southern constellation of Telescopium.

The system appears as a variable star that is dimly visible to the naked eye with an apparent magnitude that ranges from 5.32 down to 5.39, which is comparable to the maximum brightness of the planet Uranus.

Three further papers in 2020 and one in 2022 concluded that HR 6819 is simply a binary system with two main-sequence stars and no black hole at all.

[14][15] In 2003, Monika Maintz concluded that the spectrum of HR 6819 contained the signatures of two stars, though there were not enough observations to deduce an orbital period.

[9] Further observations by Rivinius et al. in 2009 were able to disentangle the spectra of the two stars, and the same team conducted thorough radial velocity measurements in 2019 and proposed the presence of an unseen stellar-mass black hole within the system.

[9] This triple star hypothesis was challenged in 2020 by Mohammadtaher Safarzadeh, Sivia Toonen, and Abraham Loeb.

Overall the spectral class is similar to the other blue giant, but the relative weakness of some luminosity-dependent lines suggest that it could be a main sequence star.