question: How do photographers/astronomers get the super colourful pictures of nebulas?
comment: Normally, nebula emits/reflects light beyond visible spectrum. Infrared, radio wave, ultraviolet, etc. Scientists took pictures of them with equipment that can capture light in those wavelength. Then they would add color to those pictures so we can appreciate the beauty of existence.
passages: The UHC filters range from 484 to 506 nm. It transmits both the O-III and H-beta spectral lines, blocks a large fraction of light pollution, and brings the details of planetary nebula and most of emission nebulae under a dark sky.
  
  Section::::Nebular filters.:Broadband.
   BULLET::::- "Our Tribe" (1991), episode of the television series Northern Exposure, written by David Assael and directed by Lee Shallat-Chemel. In this episode reluctant physician Joel Fleischman undergoes a cultural conversion after receiving a goat as a gift from a grateful village elder, who insists on "adopting" him into her tribe, and the mysterious Holling Vincoeur shuts down the Brick restaurant, ostensibly to wax the floors. Vincoeur, an amateur astronomer, tells bush pilot Maggie O'Connell about a star he is searching out in the Horsehead Nebula which he has "purchased" in honor of an old friend.
   Towards the end of the 20th century, technological improvements helped to further the study of planetary nebulae. Space telescopes allowed astronomers to study light wavelengths outside those that the Earth's atmosphere transmits. Infrared and ultraviolet studies of planetary nebulae allowed much more accurate determinations of nebular temperatures, densities and elemental abundances. Charge-coupled device technology allowed much fainter spectral lines to be measured accurately than had previously been possible. The Hubble Space Telescope also showed that while many nebulae appear to have simple and regular structures when observed from the ground, the very high optical resolution achievable by telescopes above the Earth's atmosphere reveals extremely complex structures.
   Nebulae in fiction
  
  Nebulae, often being visually interesting astronomical objects, are frequently used as settings or backdrops for works of science fiction.
  
  Section::::General uses of nebulae.
  
  BULLET::::- "The Young Black Stallion" (1989), children's book in the Black Stallion series written by Walter Farley and Steven Farley. Young Alec Ramsay imagines a legendary origin for his magnificent black: In it, the horse is none other than that celestial equine silhouetted in the Horsehead Nebula against a curtain of glowing gas and illuminated by millions of stars—an image briefly glimpsed by him at the Hayden Planetarium years before.
   Herschel assigned these to Class IV of his catalogue of "nebulae", eventually listing 78 "planetary nebulae", most of which are in fact galaxies.
  
  Section::::Observations.:Spectra.
  
  The nature of planetary nebulae remained unknown until the first spectroscopic observations were made in the mid-19th century. Using a prism to disperse their light, William Huggins was one of the earliest astronomers to study the optical spectra of astronomical objects.
   Most nebulae are of vast size; some are hundreds of light-years in diameter. A nebula that is barely visible to the human eye from Earth would appear larger, but no brighter, from close by. The Orion Nebula, the brightest nebula in the sky and occupying an area twice the diameter of the full Moon, can be viewed with the naked eye but was missed by early astronomers. Although denser than the space surrounding them, most nebulae are far less dense than any vacuum created on Earth – a nebular cloud the size of the Earth would have a total mass of only a few kilograms. Many nebulae are visible due to fluorescence caused by embedded hot stars, while others are so diffuse they can only be detected with long exposures and special filters. Some nebulae are variably illuminated by T Tauri variable stars. 
   BULLET::::13. The light of the inner portion of the solar corona is largely inherent, whereas the light of the outer portion is largely reflected sunlight, as proven at the Sumatra eclipse by means of spectroscopic and polariscopic observations.
  
  BULLET::::14. It has been shown that the principal "New Stars" have been converted into nebulae.
  
  BULLET::::15. The extraordinary motion in the nebula surrounding Nova Persei was discovered from the photograph of November 7–8, 1901.
  
  BULLET::::16. Many thousands of very accurate positions of stars have been secured with the meridian circle.
   BULLET::::- CA-II "Ca-K/Ca-H": (393 and 396 nm) For solar observing, shows the sun with the K and H Fraunhofer lines
  
  BULLET::::- N-II (658 nm and 654 nm) Often included in wider H-alpha filters
  
  BULLET::::- Methane (889 nm) allowing clouds to be seen on the gas giants, Venus and (with filter) the Sun.
  
  Section::::Nebular filters.:Narrowband.:Ultra-High Contrast filters.
  
  Known commonly as UHC filters, these filters consist of things which allow multiple strong common emission lines to pass through, which also has the effect of the similar Light Pollution Reduction filters (see below) of blocking most light sources.
   The North America Nebula is large, covering an area of more than four times the size of the full moon; but its surface brightness is low, so normally it cannot be seen with the unaided eye. Binoculars and telescopes with large fields of view (approximately 3°) will show it as a foggy patch of light under sufficiently dark skies. However, using a UHC filter, which filters out some unwanted wavelengths of light, it can be seen without magnification under dark skies. Its prominent shape and especially its reddish color (from the hydrogen Hα emission line) show up only in photographs of the area.
   There are many amateur astronomical techniques and activities associated with deep-sky objects. Some of these objects are bright enough to find and see in binoculars and small telescopes. But the faintest objects need the light-gathering power of telescopes with large objectives, and since they are invisible to the naked eye, can be hard to find. This has led to increased popularity in GoTo telescopes that can find DSOs automatically, and large reflecting telescopes, such as Dobsonian style telescopes, with wide fields of view well suited for such observing. Observing faint objects needs dark skies, so these relatively portable types of telescopes also lend themselves to the majority of amateurs who need to travel outside light polluted urban locations. To cut down light pollution and enhance contrast, observers employ ""nebular filters"" designed to admit certain wavelength and block others.
   The Cotton Candy Nebula is difficult to spot considering it is only 16" long and hardly shines. Michael E. Bakich is an Astronomy senior editor and has studied the Cotton Candy Nebula. He has confirmed that the way to spot the nebula is with the help of a 16" scope. With the help of the IRAS 17150-3224 and the nebulae being in the perfect position where the starlight is blocked, we were able to examine the ring-like structures that "cocoon" the nebula as astronomer Sun Kwok put it. The spherical ring structures around the nebulae are created throughout the red-giant stage which is the ultimate stage in stellar evolution.
   Section::::External links.
  
  BULLET::::- Australian Astronomical Observatory – IC 1340, photograph by David Malin
  
  BULLET::::- spacetelescope.com – "Uncovering the Veil Nebula", with several Hubble Space Telescope photos
  
  BULLET::::- APOD (2010-11-19) – Nebulae in the Northern Cross, showing Veil Nebula to scale in Cygnus
  
  BULLET::::- APOD (2010-09-16) – Photo of the entire Veil Nebula
  
  BULLET::::- APOD (2009-12-01) – NGC 6992: Filaments of the Veil Nebula
  
  BULLET::::- APOD (2003-01-18) – Filaments in the Cygnus Loop
  
  BULLET::::- APOD (1999-07-25) – Shockwaves in the Cygnus Loop (and underlying HST photo)
  
  BULLET::::- Bill Blair (Johns Hopkins University) – Cygnus Loop HST Photo Release
   Although these nebulae have different visibility at optical wavelengths, they are all bright sources of infrared emission, chiefly from dust within the nebulae.
  
  Section::::Types of nebulae.:Planetary nebulae.
   BULLET::::- "The Tree of Life" (2011), film written and directed by Terrence Malick. The three boys of the O'Brien family grow up in suburban Waco, Texas, raised by their nurturing mother and their strict but loving father. Thirty minutes in, the film is interrupted by—or integrated with—a 22-minute segment mystically portraying the birth of the universe, the galaxies, the stars, planets, and finally the development of life on Earth itself. For the "astrophysical" portion of this sequence, Hubble photos were stitched together and high-res images were created and broken down into layers with depth and parallax and gentle camera moves. A prominent image in this montage shows the Horsehead Nebula. Compare the use of the Eagle Nebula in the film "Contact" directed by Robert Zemeckis, above.
   Section::::Real nebulae in fiction.:NGC 2440.
  
  Planetary nebula cataloged as NGC 2440. Its central star, HD62166, is possibly the hottest known white dwarf. The nebula, situated in the Puppis constellation, was discovered in 1790 by William Herschel, who described it as a "beautiful planetary nebula of a considerable degree of brightness, not very well defined." The nebula is located about 4,000 light years from the Sun, has a spectacular appearance and is located in a rich star field.
   A second, more detailed sketch was made during his visit to South Africa in 1837. The nebula was also studied by Johann von Lamont and separately by an undergraduate at Yale College, Mr Mason, starting from around 1836. When Herschel published his 1837 sketch in 1847, he wrote:
  
  Sketches were also made by William Lassell in 1862 using his four-foot telescope at Malta, and by M. Trouvelot from Cambridge, Massachusetts and Edward Singleton Holden in 1875 using the twenty-six inch Clark refractor at the United States Naval Observatory.
  
  Section::::See also.
  
  BULLET::::- List of Messier objects
  
  BULLET::::- Messier object
   In recent years, amateur astronomers have made some notable Cygnus discoveries. The "Soap bubble nebula" (PN G75.5+1.7), near the Crescent nebula, was discovered on a digital image by Dave Jurasevich in 2007. In 2011, Austrian amateur Matthias Kronberger discovered a planetary nebula (Kronberger 61, now nicknamed "The Soccer Ball") on old survey photos, confirmed recently in images by the Gemini Observatory; both of these are likely too faint to be detected by eye in a small amateur scope.
   The most favorable period for observing the nebula in the night sky is between the months of December and April. Its southern declination makes it easier to observe from the southern hemisphere, though it is easily visible from most of the northern hemisphere as well. It appears as a faint cloud in photographs taken with high-power amateur instruments, with the help of special filters.
   Section::::Real nebulae in fiction.:Trifid Nebula.
  
  Nebula of mixed types, catalogued as M20 and located in Sagittarius. Its name means "divided into three lobes." The body is an unusual combination of an open cluster of stars (a good setting for fiction), an emission nebula (the lower, red portion), a reflection nebula (the upper, blue portion) and a dark nebula (the apparent gaps or spokes within the emission nebula that cause its three-part appearance). Viewed through a small telescope, the Trifid Nebula is a bright and peculiar object, and is thus a perennial favorite of amateur astronomers.
   When close-up, the nebula has pink clouds of glowing gas which resembles candy floss. It has been well studied over the years and extends 1,000 light-years across.
   BULLET::::11. About 40 spectroscopic binaries—that is, stars seen single in ordinary telescopes, but proven to be double by means of the spectroscope—were discovered in 1898–1902. At least one star in seven has an invisible component, observable thus far only by spectroscopic means.
  
  BULLET::::12. About 10,000 nebulae have been discovered in the past at the various observatories; but the Lick photographs show that fully 100,000 nebulae await discovery. These photographs led to the unexpected discovery that the majority of the nebulae have a spiral form—undoubted evidence of their rotation.
   BULLET::::- 1985/1989/1991: Molecular clouds are dark nebulae both in the optical and the near infrared.
  
  BULLET::::- 1986: Giant molecular complexes containing more than a million solar masses are not kinematic artifacts—as some had argued—but are well-defined objects that can be readily located throughout the galaxy.
  
  BULLET::::- 1988: Roughly half of the interstellar gas within the solar circle is molecular.
  
  BULLET::::- 2008: The enigmatic Expanding 3-kpc Arm has a Far 3 kpc symmetric counterpart on the far side of the galactic center.
   Even though the nebula has a relatively bright integrated magnitude of 7, it is spread over so large an area that the surface brightness is quite low, so the nebula is notorious among astronomers as being difficult to see. However, an observer can see the nebula clearly in a telescope using an OIII filter (a filter isolating the wavelength of light from doubly ionized oxygen), as almost all light from this nebula is emitted at this wavelength. An telescope equipped with an OIII filter shows the delicate lacework apparent in photographs, and with an OIII filter almost any telescope could conceivably see this nebula. Some argue that it can be seen without any optical aid except an OIII filter held up to the eye.
   The nebula has two main parts: the Pipe Stem with an opacity of 6 which is composed of Barnard 59, 65, 66, and 67 (also known as LDN 1773) 300′ x 60′ RA: 17 21 Dec: −27° 23′; and the Bowl of the Pipe with an opacity of 5 which is composed of Barnard 78 (also known as LDN 42) 200′ x 140′ RA: 17 33 Dec: −26° 30′.
   Section::::Common techniques.:Imaging techniques.
  
  Amateur astronomers engage in many imaging techniques including film, DSLR, LRGB, and CCD astrophotography. Because CCD imagers are linear, image processing may be used to subtract away the effects of light pollution, which has increased the popularity of astrophotography in urban areas. Narrowband filters may also be used to minimize light pollution.
  
  Section::::Scientific research.
  