NGC 6523: The Lagoon Nebula

Estimated to be between 4,000 to 6,000 light years from the Earth, in the direction of the Sagittarius constellation. It is classified as both an emission nebula and an HII region. The Lagoon Nebula was discovered by Guillaume Le Gentil in 1747 and is one of only two star-forming nebulae faintly visible to the naked eye from mid-northern latitudes. Seen with binoculars, it appears as a distinct oval cloudlike patch with a definite core. [image via]


Behind the Images of Hubble

Light and Filters: Light from astronomical objects comes in a wide range of colors, each corresponding to a particular kind of electromagnetic wave. Hubble can detect all the visible wavelengths of light plus many more that are invisible to human eyes, such as ultraviolet and infrared light. Astronomical objects often look different in these different wavelengths of light. To record what an object looks like at a certain wavelength, Hubble uses special filters that allow only a certain range of light wavelengths through. Once the unwanted light has been filtered out, the remaining light is recorded.
Enhanced Color: Enhancing the visible colors in an image often brings out an object’s subtle structural detail.
Natural/True Color: The colors in this image of a galaxy were chosen to simulate the colors that our eyes might see if we were able to visit it in a space
Representative Color: Representative color helps scientists visualize what would otherwise be invisible, such as the appearance of an object in infrared light.


NGC 7635: The Bubble Nebula

A H II region emission nebula in the constellation Cassiopeia, it lies close to the direction of the open cluster Messier 52. The “bubble” is created by the stellar wind from a massive hot, 8.7 magnitude young central star. The nebula is near a giant molecular cloud which contains the expansion of the bubble nebula while itself being excited by the hot central star, causing it to glow. It was discovered in 1787 by William Herschel.