Deep-sky objects are celestial objects that exist outside our solar system. Three major types of deep-sky objects are nebulae, star clusters, and galaxies.

It is shown that Ton 256 (z = 0.131) and PKS 2251+11 (z = 0.323) are associated with galaxies of essentially the same redshift, thus implying that these objects are at cosmological distances. The nature of Ton 256 is questionable, and it is argued that it represents a transition between Seyfert galaxies and QSOs. There is no doubt that PKS 2251+11 is a bona fide QSO; it is bright (M = -24.7), blue (B - V = 0.20, U - B = -0.84), has a starlike image under high resolution, and is a strong radio source. A peculiar emission structure near PKS 2251+11 is also discussed.

Radio positions of the three sources have been determined with the two 90-foot antennas working as an interferometer with an r.m.s. accuracy in both co-ordinates better than 10 seconds of arc. Direct photographs show that a starlike object exists within the error rectangle at each of the source positions. Exceedingly faint wisps of nebulosity are associated with the stars in 3C 48 and 3C 196. The observations are incomplete for 3C 286 in this regard. Photoelectric photometry of the stars shows each to have quite peculiar color indices, most closely resembling the colors of old novae or possibly white dwarfs, but we are not suggesting identification with these types of stars. Photometry of 3C 48 through 13 months shows the star to be variable by at least AV = 0W4. The radio flux appears to be constant. Optical spectra for 3C 48 show several very broad emission features, the most intense at X 3832 being unidentified. Spectra by Schmidt of 3C 196 and 3C 286 show other unusual features. The radio structure of the three radio stars is similar in that each has an unresolved core of <1" diameter. However, 3C 196 and 3C 286 show halos of 12" and 20", respectively, while no radio halo has been detected for 3C 48. it is shown that the radiant flux in the optical region can be computed from the radio-flux data and the theory of synchrotron radiation for 3C 48 and 3C 196, but not for 3C 286. This, together with other arguments, suggests that the optical as well as the radio flux could be due to the synchrotron mechanism, but the arguments are not conclusive. We have used the assumption of minimum total energy to compute the energy in relativistic particles and magnetic field required by the synchrotron mechanism to explain the observed emission. The magnetic field in each of the core components is near 0.1 gauss and depends mainly on the assumed angular size of the emitting region. The total energy in the core components is near 10 ergs. The rate of radiation is such that the energy in relativistic electrons must be replaced in a time scale of a few years if the value of the magnetic field determined in this way is correct. These calculations are based on a distance of 100pcs. The frequency of occurrence of radio stars is examined, and they are estimated to comprise from 5 to 10 per cent of sources in the 3C catalogue. The percentage is likely to be less for fainter sources. Rough limits have been estimated for the mean distances of these radio stars. A mean distance of approximately 100 pc is suggested if these objects are in the Galaxy. Evidence obtained since this paper was written suggests that 3C 48 has a large redshift of z = 0.3675 (Greenstein and Matthews 1963); thus these objects may be associated with a distant galaxy. The absolute magnitude of the starlike objects is M = -24.3, which is much brighter than any other known galaxy. As a radio source, 3C 48 is not very different from other identified sources. The emitted flux is the same as 3C 295 and Cygnus A, but the emitting volume is much less. The faint nebulosity does not resemble a galaxy, and it also is brighter than a normal galaxy. if caused by an explosion in the past and expanding at the velocity of light, its age would be > 1.8 X 10 years. The synchrotron lifetime calculated in the normal manner is much shorter than that inferred from the extent of the faint nebulosity. Thus either the magnetic field must be much lower than calculated, or high-energy electrons must be supplied continuously.

Whether they are tools, toys, or mirror reflections, external objects temporarily become part of who we are all the time.

A team of researchers at the Niels Bohr Institute, University of Copenhagen, have succeeded in entangling two very different quantum objects. The result has several potential applications in ultra-precise sensing and quantum communication and is now published in Nature Physics.

The universe is packed with exotic objects, including black holes, pulsars, gamma-ray bursts, magnetars, quasars, and more.

A modified Baker-Nunn camera was used to conduct a wide-field survey of 1428 square degrees of sky near the ecliptic in search of bright Kuiper Belt objects and Centaurs. This area is an order of magnitude larger than any previously published CCD survey for Centaurs and Kuiper Belt Objects. No new objects brighter than red magnitude m=18.8 and moving at a rate 1"/hr to 20"/hr were discovered, although one previously discovered Centaur 1997 CU26 Chariklo was serendipitously detected. The parameters of the survey were characterized using both visual and automated techniques. From this survey the empirical projected surface density of Centaurs was found to be SigmaCentaur(m

Central Compact Objects (CCOs) are a handful of soft X-ray sources located close to the centers of Supernova Remnants and supposed to be young, radio-quiet Isolated Neutron Stars (INSs). A clear understanding of their physics would be crucial in order to complete our view of the birth properties of INSs. We will review the phenomenologies of CCOs, underlining the most important, recent results, and we will discuss the possible relationships of such sources with other classes of INSs.