This ROSAT PSPC false-color image is of a portion of a nearby stellar wind superbubble (the Orion-Eridanus Bubble) stretching across Eridanus and Orion.
Within the constellations Orion and Eridanus and stretching across them is a soft X-ray "hot spot" known as the Orion-Eridanus Superbubble, the Eridanus Soft X-ray Enhancement, or simply the Eridanus Bubble, a 25° area of interlocking arcs of Hα emitting filaments.
Soft X-rays are emitted by hot gas (T ~ 2-3 MK) in the interior of the superbubble. This bright object forms the background for the "shadow" of a filament of gas and dust. The filament is shown by the overlaid contours, which represent 100 micrometre emission from dust at a temperature of about 30 K as measured by IRAS. Here the filament absorbs soft X-rays between 100 and 300 eV, indicating that the hot gas is located behind the filament. This filament may be part of a shell of neutral gas that surrounds the hot bubble. Its interior is energized by UV light and stellar winds from hot stars in the Orion OB1 association. These stars energize a superbubble about 1200 lys across which is observed in the optical (Hα) and X-ray portions of the spectrum.
Giacconi worked on the instrumentation for X-ray astronomy, from rocket-borne detectors in the late 1950s and early 1960s, through to Uhuru, the first orbiting X-ray astronomy satellite, the Einstein Observatory, the first fully imaging X-ray telescope put into space, and the Chandra X-ray Observatory which was launched in 1999 and is still in operation. Giacconi was awarded the Nobel Prize in Physics in 2002 "for pioneering contributions to astrophysics, which have led to the discovery of cosmic X-ray sources".
The GOES 14 spacecraft carries a Solar X-ray Imager to monitor the Sun's X-rays for the early detection of solar flares, coronal mass ejections (CME), and other phenomena that impact the geospace environment.
GOES 14 was launched into orbit on June 27, 2009 at 22:51 GMT from Space Launch Complex 37B at the Cape Canaveral Air Force Station. GOES 14 is the most recent satellite to be launched with X-ray detection capability. The importance of X-ray astronomy is exemplified in the use of an X-ray imager such as the one on GOES 14 for the early detection of solar flares, CMEs and other X-ray generating phenomena that impact the Earth.
The Crab Nebula is a remnant of an exploded star. This is the Crab Nebula in various energy bands, including a hard X-ray image from the HEFT data taken during its 2005 observation run. Each image is 6′ wide.
...that the first extrasolar X-ray source may have been the diffuse X-ray background. The first Aerobee 150 sounding rocket flight that apparently discovered Scorpius X-1 may have occurred on June 12th or 19th, 1962, and may not have been able to resolve Scorpius X-1 from the Galactic Center as the X-ray detector on board was designed to detect X-rays from the Moon.
...that as the constellation Serpens is actually divided into Serpens Cauda and Serpens Caput, Serpens X-1 is in Serpens Cauda and Serpens Caput was perhaps ignored.
...that some X-ray sources although initially detected as the first X-ray source in a respective constellation may not have received the designation X-1 as they are diffuse sources, contain several X-ray sources within the celestial object, or occupy area in two constellations. The Large Magellanic Cloud (LMC) is in Dorado and Mensa and contains many X-ray sources. Although established as the first X-ray source in Dorado, the LMC was never designated as Dorado X-1. It was first detected on October 29, 1968.
...that an occasional source such as Triangulum Australe X-1 was designated as the X-1 yet another source in the same constellation had been detected earlier and confirmed prior to its detection. The same may have happened to Orion X-1.
...that Carina X-1 (Car X-1) may have been a misprint for Cir X-1.