Telescopium is a minor constellation in the southern celestial hemisphere, one of twelve named in the 18th century by French astronomer Nicolas-Louis de Lacaille and one of several depicting scientific instruments. Its name is a Latinized form of the Greek word for telescope. Telescopium was later much reduced in size by Francis Baily and Benjamin Gould.
Upsilon Sagittarii is a spectroscopic binary star system in the constellation Sagittarius. Upsilon Sagittarii is the prototypical hydrogen-deficient binary (HdB), and one of only four such systems known. The unusual spectrum of hydrogen-deficient binaries has made stellar classification of Upsilon Sagittarii difficult.
Nu Telescopii, Latinized from ν Telescopii, is a slightly evolved star in the southern constellation Telescopium. It has an apparent visual magnitude of 5.33, allowing it to be faintly visible to the naked eye. The object is relatively close at a distance of 169 light years but is approaching the Solar System with a heliocentric radial velocity of about −12 km/s.
Mu Telescopii, Latinized from μ Telescopii is a solitary star in the southern constellation Telescopium. It has an apparent visual magnitude of 6.28, placing it near the limit of naked eye visibility. The object is relatively close at a distance of 118 light years but is receding with a heliocentric radial velocity of 8.6 km/s.
Mu Cassiopeiae, Latinized from μ Cassiopeiae, is a binary star system in the constellation Cassiopeia. This system shares the name Marfak with Theta Cassiopeiae, and the name was from Al Marfik or Al Mirfaq (المرفق), meaning "the elbow". It is dimly visible to the naked eye as a point of light with an apparent visual magnitude of 5.16. The system is located at a distance of 25 light years from the Sun based on parallax, and is moving closer with a high radial velocity of −98 km/s. This star will move into the constellation Perseus around 5200 AD.
HD 50281 is a star in the equatorial constellation of Monoceros. It is orange in hue with an apparent visual magnitude of 6.58, which lies at or below the typical limit of visibility to the naked eye. The star is located at a distance of 28.5 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −7.2 km/s.
R Aquilae is a variable star in the equatorial constellation of Aquila. It is located approximately 760 light years distant from the Sun and is drifting further away with a radial velocity of 35 km/s. This is a thermally-pulsating Mira variable that ranges in brightness from magnitude 5.3 down to 12.0 with a period of 269.84 days. The period was over 300 days when first observed, and has declined steadily since – decreasing from 320 in 1915 down to 264 in 2010, at an average rate of 0.4 days per year. The amplitude of the variation has also decreased by about a magnitude since discovery. The peak magnitude is bright enough for the star to be visible to the naked eye as a dim, red-hued star.
KK Andromedae, also known as HD 9531, is a variable star in the northern constellation of Andromeda. It has an apparent visual magnitude of 5.90, which places it near the lower limit of visibility to the naked eye even under good viewing conditions. An Alpha2 Canum Venaticorum variable, it varies in brightness by 0.012 magnitude every 0.66 days. Based upon an annual parallax shift of 7.5 mas as seen from Earth, it is located around 437 light years from the Sun. At that distance, the brightness of the star is diminished by an extinction of 0.26 magnitude due to interstellar dust.
HD 130948 or HP Boötis is a variable star with 2 brown dwarfs in the constellation Boötes. With an apparent magnitude of 6.0, it is faintly visible to the naked eye under very good observing conditions. It has a stellar classification of G1V, which means it is a main sequence star with a mass and surface temperature that are similar to the Sun. The estimated age of this star is also similar to the Sun at 4.7 billion years (Gyr) old, but it has a lower proportion of elements (63%) other than hydrogen or helium. However, a separate study in 2009 gave a much younger age of 0.5 ± 0.3 Gyr and a higher metallicity that is very similar to the Sun.
An extreme helium star is a low-mass supergiant that is almost devoid of hydrogen, the most common chemical element of the Universe. Since there are no known conditions where stars devoid of hydrogen can be formed from molecular clouds, it is theorized that they are the product of the mergers of helium-core and carbon-oxygen core white dwarfs.
SZ Crateris is a binary star system in the southern constellation Crater. Both components belong to the main sequence: the primary star has a spectral classification of K5V while the secondary is a red dwarf of spectral class M0V. The radius of the primary is about 66% the radius of the Sun, while the secondary member is only about 42% of the solar radius. In 1994, the two stars were separated by 5.1 arc seconds, which is equivalent to 112.41 astronomical units.
PV Telescopii variable is a type of variable star that is established in the General Catalogue of Variable Stars with the acronym PVTEL. This class of variables are defined as "helium supergiant Bp stars with weak hydrogen lines and enhanced lines of He and C". That is, the hydrogen spectral lines of these stars are weaker than normal for a star of stellar class B, while the lines of helium and carbon are stronger. They are a type of extreme helium star.
BX Circini is a star in the constellation Circinus. Its variability was discovered in 1995, with its apparent magnitude ranging from 12.57 to 12.62 over a period of 2 hours 33 minutes. It is currently classified as a PV Telescopii variable star, but has been put forward as the prototype of a new class of pulsating star—the BX Circini variables—along with the only other known example, V652 Herculis. This class of star is rare, possibly because this is a brief stage of stellar evolution. Its mass has been calculated to be around 40 percent that of the Sun, but the radius is a few times larger than that of the Sun. The average surface temperature is high, and has been measured at 23,390 ± 90 K using optical spectra, but 1750 K cooler if analysing it in both the visual and ultraviolet. The temperature appears to vary by 3450 K.
PZ Telescopii, also known as HD 174429 or simply PZ Tel, is a young star in the constellation Telescopium. Based on parallax measurements, it is located at a distance of 154 light-years from the Sun. The star is drifting closer with a radial velocity of −4 km/s. It is too faint to be visible to the naked eye and is classified as a BY Draconis variable that ranges in apparent visual magnitude from 8.33 down to 8.63 over a period of 22.581 hours. It is one of the closest and hence brightest pre-main-sequence stars to Earth.
Theta Hydri, Latinized from θ Hydri, is a blue-white hued star in the southern constellation of Hydrus. It is faintly visible to the naked eye with an apparent visual magnitude of +5.53. Based upon an annual parallax shift of 6.50 mas as seen from Earth, it is located approximately 502 light years. At that distance, the visual magnitude of the star is diminished by an extinction of 0.10 due to interstellar dust. It is moving away from the Sun with a radial velocity of +12.3 km/s.
HK Aquarii is a single variable star in the equatorial constellation of Aquarius. It is invisible to the naked eye, having an average apparent visual magnitude that fluctuates around 10.99. The star is located at a distance of 81 light years from the Sun based on parallax. The radial velocity is poorly constrained but it appears to be drifting further away at a rate of ~2 km/s.
HD 111395 is a single, variable star in the northern constellation of Coma Berenices. It has the variable star designation LW Com, short for LW Comae Berenices; HD 111395 is the Henry Draper Catalogue designation. The star has a yellow hue and is just bright enough to be barely visible to the naked eye with an apparent visual magnitude that fluctuates around 6.29. Based upon parallax measurements, it is located at a distance of 55.8 light years from the Sun. The star is drifting closer with a radial velocity of −8.9 km/s. It is a member of the Eta Chamaeleontis stellar kinematic group.
HD 1690 is a giant star with an orbiting exoplanet companion in the constellation of Cetus. It has an apparent visual magnitude of 9.19, which is too faint to be visible to the naked eye. The distance to this system is approximately 2,570 light years, and it is drifting further away with a radial velocity of +18.2 km/s. HD 1690 has no known companion star, making it a single star system.
PW Telescopii, also known as HD 183806 or simply PW Tel, is a solitary variable star located in the southern constellation Telescopium. It has an average apparent magnitude of 5.58, making it faintly visible to the naked eye. Based on parallax measurements from the Gaia satellite, the star is estimated to be 395 light years distant. It appears to be approaching the Solar System with a heliocentric radial velocity of −10 km/s. The value is somewhat constrained, having an uncertainty of 26%. At its current distance, PW Tel's brightness is diminished by 0.05 magnitudes due to interstellar dust.
HD 189080, also known as HR 7621 or rarely 74 G. Telescopii, is a solitary orange-hued star located in the southern constellation Telescopium. It has an apparent magnitude of 6.18, placing it near the limit for naked eye visibility. Gaia DR3 parallax measurements place it at a distance of 357 light years and it is currently receding rapidly with a heliocentric radial velocity of 66.9 km/s. At its current distance, HD 189080's brightness is diminished by 0.17 magnitudes due to extinction from interstellar dust. It has an absolute magnitude of +1.1.
