French astronomer Nicolas-Louis de Lacaille charted and designated ten stars with the Bayer designationsAlpha through to Iota in 1756. A star in neighbouring Indus that Lacaille had labelled Nu Indi turned out to be in Microscopium, so Gould renamed it Nu Microscopii. Francis Baily considered Gamma and Epsilon Microscopii to belong to the neighbouring constellation Piscis Austrinus, but subsequent cartographers did not follow this. In his 1725 Catalogus Britannicus, John Flamsteed labelled the stars 1, 2, 3 and 4 Piscis Austrini, which became Gamma Microscopii, HR 8076, HR 8110 and Epsilon Microscopii respectively. Within the constellation's borders, there are 43 stars brighter than or equal to apparent magnitude 6.5.[c]
Depicting the eyepiece of the microscope is Gamma Microscopii, which—at magnitude of 4.68—is the brightest star in the constellation. Having spent much of its 620-million-year lifespan as a blue-white main sequence star, it has swollen and cooled to become a yellow giant of spectral type G6III, with a diameter ten times that of the Sun. Measurement of its parallax yields a distance of 223 ± 8 light years from Earth. At around 2.5 times the mass of the Sun, it likely passed within 1.14 and 3.45 light-years of the Sun some 3.9 million years ago, possibly massive enough and close enough to disturb the Oort cloud.Alpha Microscopii is also an ageing yellow giant star of spectral type G7III with an apparent magnitude of 4.90. Located 400 ± 30 light-years away from Earth, it has swollen to 17.5 times the diameter of the Sun. Alpha has a 10th magnitude companion, visible in 7.5 cm telescopes, though this is a coincidental closeness rather than a true binary system.Epsilon Microscopii lies 166 ± 5 light-years away, and is a white star of apparent magnitude 4.7, and spectral type A1V.Theta1 and Theta2 Microscopii make up a wide double whose components are splittable to the naked eye. Both are white A-class magnetic spectrum variable stars with strong metallic lines, similar to Cor Caroli. They mark the constellation's specimen slide.
Many notable objects are too faint to be seen with the naked eye. AX Microscopii, better known as Lacaille 8760, is a red dwarf which lies only 12.9 light-years from the Solar System. At magnitude 6.68, it is the brightest red dwarf in the sky.BO Microscopii is a rapidly rotating star that has 80% the diameter of the Sun. Nicknamed "Speedy Mic", it has a rotation period of 9 hours 7 minutes. An active star, it has prominent stellar flares that average 100 times stronger than those of the Sun, and are emitting energy mainly in the X-ray and ultraviolet bands of the spectrum. It lies 218 ± 4 light-years away from the Sun.AT Microscopii is a binary star system, both members of which are flare star red dwarfs. The system lies close to and may form a very wide triple system with AU Microscopii, a young star which appears to be a planetary system in the making with a debris disk. The three stars are candidate members of the Beta Pictoris moving group, one of the nearest associations of stars that share a common motion through space.
HD 205739 is a yellow-white main sequence star of spectral type F7V that is around 1.22 times as massive and 2.3 times as luminous as the Sun. It has a Jupiter-sized planet with an orbital period of 280 days that was discovered by the radial velocity method.WASP-7 is a star of spectral type F5V with an apparent magnitude of 9.54, about 1.28 times as massive as the Sun. Its hot Jupiter planet—WASP-7b—was discovered by transit method and found to orbit the star every 4.95 days.HD 202628 is a sunlike star of spectral type G2V with a debris disk that ranges from 158 to 220 AU distant. Its inner edge is sharply defined, indicating a probable planet orbiting between 86 and 158 AU from the star.
Describing Microscopium as "totally unremarkable", astronomer Patrick Moore concluded there was nothing of interest for amateur observers.NGC 6925 is a barred spiral galaxy of apparent magnitude 11.3 which is lens-shaped, as it lies almost edge-on to observers on Earth, 3.7 degrees west-northwest of Alpha Microscopii.SN 2011ei, a Type II Supernova in NGC 6925, was discovered by Stu Parker in New Zealand in July 2011.NGC 6923 lies nearby and is a magnitude fainter still. The Microscopium Void is a roughly rectangular region of relatively empty space, bounded by incomplete sheets of galaxies from other voids. The Microscopium Supercluster is an overdensity of galaxy clusters that was first noticed in the early 1990s. The component Abell clusters 3695 and 3696 are likely to be gravitationally bound, while the relations of Abell clusters 3693 and 3705 in the same field are unclear.
The stars that comprise Microscopium are in a region previously considered the hind feet of Sagittarius, a neighbouring constellation.John Ellard Gore wrote that al-Sufi seems to have reported that Ptolemy had seen the stars but he (Al Sufi) did not pinpoint their positions. Microscopium itself was introduced in 1751–52 by Lacaille with the French name le Microscope, after he had observed and catalogued 10,000 southern stars during a two-year stay at the Cape of Good Hope. He devised fourteen new constellations in uncharted regions of the Southern Celestial Hemisphere not visible from Europe. All but one honoured instruments that symbolised the Age of Enlightenment. Commemorating the compound microscope, the Microscope's name had been Latinised by Lacaille to Microscopium by 1763.
^While parts of the constellation technically rise above the horizon to observers between 45°N and 62°N, stars within a few degrees of the horizon are to all intents and purposes unobservable.
^Objects of magnitude 5.0 are barely visible to the unaided eye in the night skies of city-suburban transition areas.
^Objects of magnitude 6.5 are among the faintest visible to the unaided eye in suburban-rural transition night skies.
^ abCooper, Tim (2003). "Presidential address: Amateur Observations – Successes and Opportunities". Monthly Notes of the Astronomical Society of Southern Africa. 62: 234–240. Bibcode:2003MNSSA..62..234C.
^Pereira, C.B.; Roig, F. (2009). "High-Resolution Spectroscopic Observations of Four Yellow-Type Symbiotic Stars: CD-43°14304, Hen 3-1213, Hen 3-863, and StHα 176". The Astronomical Journal. 137 (1): 118–128. Bibcode:2009AJ....137..118P. doi:10.1088/0004-6256/137/1/118.CS1 maint: uses authors parameter (link)
^López-Morales, Mercedes; Butler, R. Paul; Fischer, Debra A.; Minniti, Dante; Shectman, Stephen A.; Takeda, Genya; Adams, Fred C.; Wright, Jason T.; Arriagada, Pamela (2008). "Two Jupiter-Mass Planets Orbiting HD 154672 and HD 205739". The Astronomical Journal. 136 (5): 1901–1905. arXiv:0809.1037. Bibcode:2008AJ....136.1901L. doi:10.1088/0004-6256/136/5/1901.
^Hellier, Coel; Anderson, D.R.; Gillon, M.; Lister, T.A.; Maxted, P.F.L.; Queloz, D.; Smalley, B.; Triaud, A.H.M.J.; West, R.G.; Wilson, D.M.; Alsubai, K.; Bentley, S.J.; Cameron, A. Collier; Hebb, L.; Horne, K.; Irwin, J.; Kane, S.R.; Mayor, M.; Pepe, F.; Pollacco, D.; Skillen, I.; Udry, S.; Wheatley, P.J.; Christian, D.J.; Enoch, R.; Haswell, C.A.; Joshi, Y.C.; Norton, A.J.; Parley, N.; Ryans, R. (2008). "Wasp-7: A Bright Transiting-Exoplanet System in the Southern Hemisphere". The Astrophysical Journal Letters. 690 (1): L89–L91. arXiv:0805.2600. Bibcode:2009ApJ...690L..89H. doi:10.1088/0004-637X/690/1/L89.
Wagman, Morton (2003). Lost Stars: Lost, Missing and Troublesome Stars from the Catalogues of Johannes Bayer, Nicholas Louis de Lacaille, John Flamsteed, and Sundry Others. Blacksburg, Virginia: The McDonald & Woodward Publishing Company. ISBN978-0-939923-78-6.