The Hubble observatory, launched and deployed in April 1990, is the first major optical telescope to be placed in space, the ultimate mountaintop. Above the distortion of the atmosphere — far above rain clouds and light pollution — Hubble has an unobstructed view of the universe. Scientists have used Hubble to observe the most distant stars and galaxies as well as the planets in our solar system. It marked the most significant advance in astronomy since Galileo’s telescope. Since its launch, our view of the universe and our place within it has never been the same.

Hubble’s high-definition panoramic view of the Andromeda galaxy

The largest NASA Hubble Space Telescope image ever assembled, this 1.5-billion-pixel view of the Andromeda galaxy is the sharpest large composite image ever taken of our galactic next-door neighbor. Though the galaxy is more than 2 million light-years away, the Hubble telescope is powerful enough to resolve individual stars in a 61,000-light-year-long section of the galaxy’s pancake-shaped disk. The highest-resolution photo has 1,000 times the resolution of a normal high-definition picture and was obtained by viewing the galaxy in near-ultraviolet, visible, and near-infrared wavelengths. “Never before have astronomers been able to see individual stars inside an external spiral galaxy over such a large contiguous area,” NASA said on its website.

NGC 4217, 60 million light-years away

Sweep of dust filaments

The NGC 4217 galaxy is seen almost perfectly edge on and is an ideal candidate for studying the nature of extraplanar dust structures — the patterns of gas and dust above and below the plane on the galaxy, seen above as brown wisps. These tentacle-like filaments are visible in the Hubble image only because the contrast with their surroundings is so high. This implies that the structures are denser than their surroundings.

NGC 1501, 5,000 light-years away

Bubbly Nebula

Although the central star blasted off its outer shell long ago, it still remains very hot and luminous. But the star is quite tricky for observers to spot through modest telescopes. The subject of many studies, this star has one unusual feature: it seems to be pulsating, varying significantly in brightness over a typical time scale of just half an hour. While variable stars are not unusual, it is uncommon to find one at the heart of a planetary nebula.

NGC 6861, 131 million light-years away

Third kind of galaxy

Most galaxies are spiral or elliptical. The NGC 6861 galaxy, discovered in 1826, is neither; it is a lenticular galaxy, which means it has features of both spiral and elliptical galaxies. The relationships between these three kinds of galaxies are not yet well understood. Scientists say a lenticular galaxy could be the result of two galaxies merging or it could be a faded spiral that has run out of gas and lost its arms.

NGC 986, 56 million light-years away

Spiral in a furnace

Barred spiral galaxies are spiral galaxies with a central bar-shaped structure composed of stars. NGC 986 — located in the constellation of Fornax (the furnace) — has the characteristic S-shaped structure of this type of galaxy. Young blue stars dot the galaxy’s arms and the core of the galaxy is also aglow with star formation. Sources: Hubble, NASA, European Space Agency