| 30 Dec 04 |  | Beta Ceti | An X-ray bright giant star 95 light years from Earth. |
| 23 Dec 04 |  | DB00-6 | A star cluster in the direction of the Galactic Center. |
| 23 Dec 04 |  | DB01-42 | A star cluster in the direction of the Galactic Center. |
| 23 Dec 04 |  | DB00-58 | A star cluster in the direction of the Galactic Center. |
| 14 Dec 04 |  | 3C58 | A supernova remnant 10,000 light years from Earth. |
| 22 Nov 04 |  | SDSSp J1306 | A quasar seen as it was 12.7 billion light years ago. |
| 09 Nov 04 |  | Proxima Centauri | A red dwarf star 4 light years from the Sun. |
| 29 Oct 04 |  | M87 Core | A galaxy in the constellation of Virgo. |
| 26 Oct 04 |  | NGC 4555 | A large, elliptical galaxy about 300 million light years from Earth. |
| 06 Oct 04 |  | Kepler's Supernova Remnant | The remains of a supernova first seen in 1604. |
| 23 Sep 04 |  | Mouse
(G359.23-0.82) | A pulsar wind nebula about 16,000 light years from Earth. |
| 08 Sep 04 |  | Fornax Cluster | A nearby galaxy cluster about 65 million light years from Earth. |
| 23 Aug 04 |  | Cassiopeia A | The remnant of a supernova 10,000 light years from Earth. |
| 13 Aug 04 |  | Abell 2125 | A massive galaxy cluster about 3 billion light years from Earth. |
| 04 Aug 04 |  | GRB 031203 | A gamma ray burst 1.3 billion light years from Earth. |
| 28 Jul 04 |  | Quintuplet Cluster | A dense young star cluster about 26,000 light years from Earth. |
| 22 Jul 04 |  | McNeil's Nebula | A source illuminating a nebula 1300 light years from Earth. |
| 06 Jul 04 |  | Cloverleaf Quasar
(H1413+117) | A quasar about 11 billion light years from Earth. |
| 28 Jun 04 |  | H1504+65 | The hottest known white dwarf. |
| 13 Jun 04 |  | Hot Gas in Galactic Center | A 130 light year region in the center of the Milky Way. |
| 02 Jun 04 |  | W49B | A barrel-shaped supernova remnant about 35,000 light years from Earth. |
| 01 Jun 04 |  | GOODS CDFS 033213.9-275000 | Supermassive black hole in a young galaxy billions of light years from Earth. |
| 01 Jun 04 |  | GOODS CDFS 033251.6-275212 | Supermassive black hole in a young galaxy billions of light years from Earth. |
| 18 May 04 |  | Abell 2029 | A galaxy cluster 1 billion light years away. |
| 18 May 04 |  | MS 2137.3-2353 | A galaxy cluster 3.5 billion light years away. |
| 18 May 04 |  | MS 1137.5+6625 | A galaxy cluster 6.7 billion light years away. |
| 10 May 04 |  | M87 | Long-exposure image of the giant elliptical galaxy M87. |
| 20 Apr 04 |  | SNR 0540-69.3 | A massive star explosion 160,000 light years away. |
| 10 Apr 04 |  | MGG11 | A mid-size black hole in the star cluster MGG 11. |
| 05 Apr 04 |  | Titan | The shadow of Saturn’s largest moon on the Crab Nebula. |
| 24 Mar 04 |  | N49B | The remains of an exploded star reveal large concentrations of magnesium. |
| 08 Mar 04 |  | Saturn | The 6th planet from the Sun. |
| 01 Mar 04 |  | M101 | A possible new class of X-ray sources. |
| 01 Mar 04 |  | M83 | A possible new class of X-ray sources. |
| 01 Mar 04 |  | NGC 4697 | A possible new class of X-ray sources. |
| 01 Mar 04 |  | Whirlpool Galaxy
(M51) | A possible new class of X-ray sources. |
| 18 Feb 04 |  | RX J1242-11 | A star being torn apart by the tidal forces of a black hole. |
| 30 Jan 04 |  | V471 Tauri | A white dwarf star in a close orbit with a normal Sun-like star. |
| 07 Jan 04 |  | Antennae | This montage of Chandra images shows a pair of interacting galaxies known as The Antennae. |
| 06 Jan 04 |  | C153 | A galaxy being ripped apart as it races at 4.5 million miles per hour. |
| 05 Jan 04 |  | SS 433 | Jets from SS 433 may be originating five times closer to the black hole than previously thought. |
| 02 Jan 04 |  | RDCS 1252.9-2927 | A color composite image shows the X-ray light from 70-million-degree Celsius gas in the cluster. |
