Astrophotography of the Sun by Alan Friedman
by Dr. Robert Berdan
July 17, 2012
(All photographs by Alan Friedman used with permission)
The sun is our nearest star and it is the main reason we have life on earth. Most photographers capture images of the sun in landscapes, especially around sunrise and sunset. For most of us all we see is a round bright ball of intense light. If we look at the sun with a telescope, and special solar filters that protect our eyes, the most discernable feature are sunspots when they are present. These cool darker regions of the sun follow an 11 year cycle increasing in number at solar max and then decreasing at solar minimum. Our next solar max is predicted to occur in the Spring 2013. As the number of sunspots increases so does Solar activity which can affect our lives on earth. A massive solar discharge (coronal mass ejection) can wipe out electrical power grids, satellites and possibly other electronic devices. The most obvious effect is that we will see an increase in Aurora activity which is why I am so interested in the sun.
Having recently spent some time with Canadian astrophotographer, Jack Newton, my interest in astrophotography has been peeked. While searching the web I came across another amateur astrophotographer, Alan Friedman. Alan's images of the sun are simply spectacular and he has agreed to allow me to share some of his images with you. Alan's images of the sun are so spectacular he has been featured in numerous blogs, magazines and even TV shows. The amazing thing is he takes these pictures in his backyard in Buffalo, New York and astronomy is Alan's hobby.
View original image on Alan's web site
Sun photographed with a solar telescope using a Hydrogen alpha filter (656.3 nm). The pictures consists of several different exposures of the sun that are combined or stacked together. The fine filaments are solar prominences seen end on. Dark regions are small sunspots while brighter plage (spots) mark highly magnetized regions.
In this image of the sun taken in black and white and then false coloured you can see the transit of Venus at the top right. You can also see the structure of the filaments on the surface of the sun while around the edge there are several solar flares. The surface detail visible in this image is incredible. View original enlarged image here.
Large group of sunspots - View original image here
Closeup of sunspots using a white light solar filter. The number of sunspots varies on the surface of the Sun peaking at solar max in the 11 year sunspot cycle. Sunspots are not stationary, but move around the sun and last from a few days to a few weeks. These cooler regions of the sun also feature powerful magnetic fields that can send protons and electrons into space that trigger the Aurora borealis (Northern lights) on earth. Sunspots are produced by intense magnetic fields that emerge from the interior of the Sun through the photosphere. Sunspots tend to travel in pairs of opposite magnetic polarity. The Sun rotates with a period of about 25 days so the same sun spots can be visible for about a week. Achieving sharp images like the one above is difficult due to the refraction of light caused by the heating of the atmosphere which also causes stars to twinkle at night. To obtain such sharp images Alan took numerous images, then stacked and processed them so that only the sharpest images are retained.
Gif animation of sunspots by Alan Friedman. Original movie can be viewed here.
Massive Floater/ Fine art print 17x22" on heavyweight archival stock/ $175. Click here to order this print through the secure shopping cart at greatarrow.com. View original image here.
Blue sun - taken in BW and image processed to provide the false colour and show off the texture of the photosphere.
View
The Deep Blue Sea - view original image enlarged
"I can only share a little snippet of this story. I hope you can visit here for the big picture. I arrived at Mount Wilson Observatory the day before the transit of Venus and had just enough time to get everything unpacked and set up for a test run. I took two streams of video to make sure the computer and cameras were all happy and talking to each other. I forgot about these files in the excitement of June 5th. Looking back through the files while archiving the 200 gigabytes of data from my trip, the conditions on June 4th were way better than the following day… in fact, it is some of the best solar seeing I’ve experienced in some time."
Alan Friedman (from his blog)
Double Transit: Video by Alan Friedman showing the sun setting behind one of the towers in the jungle of communications hardware on top of Mount Wilson. The tower in the movie is the tall one to the left in this photo.
Alan's telescope "Little Big Man" and camera setup for photographing the Sun. Alan takes multiple images and then processes them using a variety of programs. Alan's solar telescope is equipped with a Hydrogen alpha filter, these filters cost several thousands of dollars depending on their size. Hydrogen alpha filters allow a narrow spectrum of light to pass through. One of the main obstacles in getting sharp images is the volatility of the atmosphere especially during the day. To achieve sharp pictures, Alan takes 90 seconds of streaming video and then selects the sharpest frames. He uses a Grasshopper CCD camera by Point Grey Research. On processing, he works on a Mac computer with AstroIIDC and Adobe Photoshop CS6. I often combine 2 exposures, but do sometimes use three and sometimes one when working with a 16 bit camera.
Alan's astrophotography is not limited to the sun, his web site also features beautiful pictures of Saturn, Jupiter, nebulae and the aurora borealis. Alan's photographs show that sometimes the most amazing photographs can be taken in your own backyard.
Please note never look at the sun through a telescope or binoculars if they do not have special solar filters - you can cause permanent eye damage. The easiest way to view the sun is to attach and economical white-light solar filter purchased from a reputable astronomy store. These filters will permit you to view sunspots, but the finer details on the sun will not be visible. Alternatively you can use No 14 welders filters to view the sun, but be sure they are #14 not #12 which are too light. H-alpha filters cost between $700 to $10,000 depending on the aperture and bandwidth. Solar telescopes with Hydrogen-alpha filters can be purchased for a few thousand dollars see links below for more information.
Astrophotography can be technically challenging and although I am just a beginner I am gaining an appreciation of the technical skill required in operating the telescope and processing the digital images. It is an exciting area and one I will be featuring more often on this site in the future. I thank Alan Friedman for allowing to me show his amazing photographs. RB
By day, Alan Friedman is an artist, award winning greeting card designer and president of Great Arrow Graphics. By night he is an avid astro-photographer, recording the solar system from his backyard in Buffalo, NY. His images of the sun, moon and planets are featured frequently on NASA's popular websites Spaceweather.com and Astronomy Picture of the Day. and in exhibitions, including the touring show for the International Year of Astronomy, From the Earth to the Universe. His techniques for planetary imaging have been the subject of interviews on MSNBC's the TODAY show, articles in Sky and Telescope magazine and a column at Space.com. Alan holds a BFA in studio art from the State University of NY at Buffalo and lives in Buffalo today. He is currently president of the Buffalo Astronomical Association and holds the title of Research Associate in Astronomy at the Buffalo Museum of Science. To find out more about Alan, visit his astronomy website, avertedimagination.com.
E-mail: avertimag@greatarrow.com
Website: avertedimagination.com
Blog: alanfriedman.tumblr.com
