Ever been out at night and taken some photographs of a glowing, low-slung harvest moon? Or have you browsed through images taken by the Hubble Space Telescope? If you answered yes to either of these questions, you've already been exposed to the world of astrophotography.
Astrophotography is simply taking a photograph of an object in space, whether it's with a point-and-shoot camera, the Hubble Space Telescope or any other type of camera. And the subject matter can include anything from the moon to the Milky Way.
In 1840, John William Draper's daguerreotype of the moon became the first astrophotograph ever taken in North America [source: Canada Under the Stars]. Early forays into photography, like the daguerreotype, and today's modern cameras involve capturing the light reflected off of various objects. In the case of astrophotography, this light happens to come from the cosmos. To understand how cameras capture light and store images, read How Cameras Work for more information.
Searching for subjects often drew the eyes of early photographers skyward, and astrophotography has remained a popular pastime ever since. Amateur and professional astrophotographers aim their telescopes and cameras toward the heavens to capture vivid, breathtaking shots of everything from nearby stellar neighbors to nebula too far to comprehend.
As the study of space and photography techniques have progressed, observatories and orbiting telescopes have expanded the tradition of photographing astronomical objects. To this day, scientists constantly push the envelope, developing new techniques and tools to achieve greater photographic precision at vast distances.
Dying to know if anyone has taken an astrophotograph of the man on the moon? Let's take a closer look at astrophotography and discover if you could be the next photographer to the stars.
Many hobbyists and professional photographers use film and digital cameras to take astrophotographs; and some enthusiasts are also using webcams and other types of video cameras. These photographers can mount and hook up recording instruments to different telescopes of varying magnification levels in order to improve imaging power. Telescopes and tripods also steady the devices for clearer images.
Other equipment can come in handy as well. Guide scopes and guiders help align your camera for long exposures as the Earth rotates. Timed remotes take the pressure off precisely timed long, multiple exposures. Telephoto lenses can make everything larger than life, so to speak, by increasing the size of the photographed object in the frame. And that's just a few of the pieces of equipment that can help to improve the quality of astrophotographs.
Equipment alone might not solve every challenge associated with astrophotography. For example, you must avoid interference from the turbulent atmosphere, airborne dust particles and moisture, light pollution and pesky insects. Also, you'll want a way to keep long exposures in focus as the Earth rotates. Experienced astrophotographers have discovered a few ways to overcome some of these obstacles, like creating handmade brackets that allow for the use of a shutter release cable (to improve camera stability). Many space enthusiasts offer tips on their own Web sites or through astrophotography publications (visit the links on the Lots More Information page to find some of these tips).
The trick to taking good astrophotographs is to overcome these obstacles, while experimenting with different shutter speeds and aperture settings at the same time. Since astrophotographs often depict faint objects, one of the main objectives is to get enough light in the shot. For extremely faint objects, the added goal is to get enough duplicates of that image in order to layer them together later. More of this is explained in How Photographic Film Works.
While astrophotographs are often taken with long shutter exposures, they can also be created by shooting many short exposures that are later combined. Once the images are taken, they can be layered with the use of computer software to provide clearer, more vivid composite photos. Often, astrophotographers must stack the images in order to get a high-quality finished product. Capturing multiple exposures is a fairly common technique for photographing events like eclipses. Astrophotographers take a wide-angle shot every few minutes to record the event's progression, and then have all the stages appear as one finished image.
Another interesting technique is to make use of the blurring that occurs because of Earth's rotation. These star trail images might portray a lunar eclipse as a color-changing, streaking blur or an entire star field circling a central hub.
Astrophotographs taken at observatories tend to be more sophisticated than amateur efforts. For example, take Hawaii's Keck Observatory. It has many supersensitive instruments that are busy collecting incredibly high-resolution images and spectrum analyses of objects all over the nighttime sky. Through its detailed pictures, Keck allows us to learn more about puny brown dwarfs, raging weather on Jupiter, super dense galaxies and other celestial happenings.
Needless to say, Keck's facilities aren't available for just anybody to use -- scientists must submit proposals that detail their project plans for consideration. Many smaller observatories, however, are open for public viewing on certain evenings. Also, there may be an astronomy club in your area that gets together for stargazing and astrophotography sessions.
Now that we've looked at what can be accomplished right here on terra firma with some commonplace gear or a trip to an observatory, let's see what the heavy hitters are looking at from above.
Astrophotography in Orbit
Now that we've explored the down-to-earth perspective, let's examine the functions of astrophotography in orbit. Probably the most familiar photographs taken in space have come from the Hubble Space Telescope. However, the Spitzer Space Telescope, the newest and final telescope of NASA's Great Observatories program, has been stealing the show lately.
Originally called the Space Infrared Telescope Facility, Spitzer launched from Cape Canaveral in August 2003. In June 2008, Spitzer's masterpiece was unveiled. The telescope collected more than 800,000 photographs in several varying infrared wavelengths which were composited and stitched together to create a gorgeous, false-color map of the galaxy [source: Clavin].
Spitzer's imaging abilities see clear to the other side of the Milky Way by accessing the infrared portion of the electromagnetic spectrum. Infrared frequencies lie between those of microwaves and visible wavelengths (what we perceive as light) on the spectrum. These images must be false-color because people can't see anything at infrared wavelengths. You can learn more about light and its frequencies by reading How Light Works. Hubble was used to observe ultraviolet, visible and near-infrared wavelengths, but only with Spitzer have we been able to jump through the cosmic dust and clutter to see distant reaches of the galaxy with such amazing clarity.
And with that sight comes amazing revelations. Researchers can now sift through a wealth of details concerning the layout and composition of the galaxy. For instance, early study of the Spitzer images is giving researchers a clearer idea of the Milky Way's shape. These pictures suggest that the Milky Way is a barred-spiral galaxy, leading scientists to believe it has only two major spiral arms, which extend from each end of the long central bar. This is an evolution from early theories about the Milky Way. For many decades, we pictured it as a four-armed, spiral galaxy with a central galactic bulge. More recently, astronomers theorized our galaxy was a barred-spiral galaxy, but one that still boasted four major arms.
The other NASA observatories orbiting the planet have also played their parts in expanding our knowledge of the universe. Perched high above the corrupting interference of the atmosphere, they transmit images received prior to atmospheric disturbance. For example, Hubble's phenomenally high-powered imagery of the cosmos has increased our understanding of both near- and deep-space objects. The Chandra X-Ray Observatory has been busy gathering information on cosmic phenomena such as supernovas and black holes, and will continue to do so until at least the year 2009. The Compton Gamma Ray Observatory, in operation from 1991 to 1999, cast its lens toward solar flares, quasars and various cosmic interactions.
Now that you know about the world of astrophotography, will space become your muse? Learn more about astrophotography and space by visiting the links on the next page.
Related HowStuffWorks Articles
More Great Links
- "About Spitzer." Jet Propulsion Laboratory. (6/3/2008) http://www.spitzer.caltech.edu/about/index.shtml
- Adams, Denise. "Photography of things beyond Earth." NASA Langley Research Center. 10/26/2007. (6/5/2008) http://www.nasa.gov/centers/langley/news/researchernews/rn_astrophotography.html
- "A GLIMPSE of the Milky Way." GLIMPSE/MIPSGAL Image Viewer by the Space Science Institute. (6/5/2008) http://www.alienEarths.org/glimpse/
- Aguirre, Edwin. "Astro Imaging with Digital Cameras." Sky and Telescope. (6/3/2008) http://www.skyandtelescope.com/howto/astrophotography/3304331.html?page=5&c=y
- Barker, George. "Memoir of John William Draper 1811-1882." Kessinger Publishing 2006. (6/5/2008) http://books.google.com/books?id=5CrCQwJ2su8C&dq=Memoir+of+ John+William+Draper:+1811-1882&source=gbs_summary_s&cad=0
- Clavin, Whitney. "Spitzer Captures Stellar Coming of Age in Our Galaxy." Jet Propulsion Laboratory. 6/3/2008. (6/5/2008) http://www.spitzer.caltech.edu/Media/releases/ssc2008-11/release.shtml
- Clavin, Whitney. "Two of the Milky Way's Spiral Arms Go Missing." Jet Propulsion Laboratory. 6/3/2008. (6/5/2008) http://www.spitzer.caltech.edu/Media/releases/ssc2008-10/release.shtml
- Coco, Mark. "Guiding a Telescope for Imaging." Sky and Telescope. (6/3/2008) http://www.skyandtelescope.com/howto/astrophotography/3304266.html
- Dobbins, Thomas. "Night! Camera! Action!" Sky and Telescope. (6/3/2008)http://www.skyandtelescope.com/howto/astrophotography/3437996.html
- Dyer, Alan. "Deep-Sky Photography Made Easy." Sky and Telescope. (6/3/2008) http://www.skyandtelescope.com/howto/astrophotography/Deep-Sky_Photography.html
- Espenak, Fred. "How to Photograph a Lunar Eclipse." MrEclipse.com. 2/28/2008. (6/3/2008) http://www.mreclipse.com/LEphoto/LEphoto.html
- Freidman, Alan. "A Webcam Primer: Secrets of Astrophotography." Starry Night Times. 9/2005. (6/5/2008) http://www.starrynight.com/sntimes/2005-09.html
- "Hubble Space Telescope." Encyclopedia Britannica. (6/5/2008) http://www.britannica.com/EBchecked/topic/274508/Hubble-Space-Telescope
- "Instrumentation." W. M. Keck Observatory. (6/5/2008) https://www.keckobservatory.org/instrumentation.php
- Lodriguss, Jerry. "Catching the Light: Astrophotography." (6/3/2008)http://www.astropix.com/
- Nicolaides, Tom. "Astrophotography with a DSLR." Hazeldale Observatory. (6/5/2008) http://www.first-light.org/index.html
- "Photographic Plates." Canada Under the Stars. (6/12/2008) http://astro-canada.ca/_en/a2306.html
- "Photography" Encyclopedia Britannica. (6/5/2008) http://www.britannica.com/EBchecked/topic/457919/photography
- Rao, Joe. "Spacewatch Friday - Astrophotography 101: How to Take Stellar Pictures." Space.com. 6/27/2003. (6/5/2008) http://www.space.com/spacewatch/astrophotography_101_030627.html
- "Spitzer Space Telescope." NASA Facts. (6/5/2008) http://www.spitzer.caltech.edu/Media/spitzer-fact-sheet1.pdf