Wisps of dust fill the space between the stars. This dust is usually invisible, subtly acting to dim the light of more distant stars. Sometimes this dust is thick and prominent as dark patches on otherwise bright emission nebulae. Other times this dust may show itself by reflecting the light of bright, nearby stars. Because bright stars tend to be blue, and because dust reflects blue light more easily than red, the resulting reflection nebula usually appears blue. Pictured above is the reflection nebula Sharpless 2-1 in the constellation of Scorpius (text adapted from APOD). This is a mosaic of 2 panels. Apo TEC140 (140/f7.2) - FLI Proline 16803 - Ha (300m) L (250m) R (140m) G (110m) B (120m) - Warrumbungle Observatory, Coonabarabran, NSW, Australia
Sculpted by stellar winds and radiation, the star factory known as Messier 17 lies some 5,500 light-years away in the nebula-rich constellation Sagittarius. Stellar winds and energetic light from hot, massive stars formed from M17's stock of cosmic gas and dust have slowly carved away at the remaining interstellar material producing the cavernous appearance and undulating shapes. M17 is also known as the Omega Nebula or the Swan Nebula (text adapted from APOD).Apo TEC140 (140/f7.2) - FLI Proline 16803 - Ha (290m) R (80m) G (80m) B (90m) - Warrumbungle Observatory, Coonabarabran, NSW, Australia
This shock wave plows through space at over 500,000 kilometers per hour. Moving right to left in the beautifully detailed color composite, the thin, braided filaments are actually long ripples in a sheet of glowing gas seen almost edge on. Cataloged as NGC 2736, its narrow appearance suggests its popular name, the Pencil Nebula. About 5 light-years long and a mere 800 light-years away, the Pencil Nebula is only a small part of the Vela supernova remnant. The Vela remnant itself is around 100 light-years in diameter, the expanding debris cloud of a star that was seen to explode about 11,000 years ago. Initially, the shock wave was moving at millions of kilometers per hour but has slowed considerably, sweeping up surrounding interstellar gas. (text adapted from APOD).Apo TEC140 (140/f7.2) - FLI Proline 16803 - Ha (330m) OIII (200m) R (90m) G (100m) B (100m) - Warrumbungle Observatory, Coonabarabran, NSW, Australia
