|Great Hercules Cluster M13 - DSLR
The colossus of globular clusters, the Great Hercules Cluster can be seen with the unaided eye from a dark sky site. It packs about a half million stars in a region only 150
light years across, orbiting our galaxy like a giant satellite 20,000 light years away. The brightest stars in this image are red giants, thousands of times brighter than our sun. At its
core, the glare of brilliant suns would obscure the remainder of the universe. Of course, planets are unlikely in the center of a globular cluster, as frequent gravitational
interactions with other stars would strip away plantets. Due north of M13 (above it in this photo) is the orange giant star HIP 81848, a type K star late in its evolution. In the
upper right of the above image, galaxy NGC 6207 shines at a dim 12th magnitude. Between this galaxy and M13 is the dim 15th magnitude edge-on spiral galaxy IC 4617. The
lower left shows blue-white type A star HIP 81673.
The image above was obtained with a Canon 60Da through a TEC 140 mm refractor on an AP 900 GTO mount. A total of 12 x 5-minute exposures were obtained, for a total
exposure time of one hour. Images were acquired using Maxim DSLR, using a Lodestar guider with dithering, and calibrated with dark and flat frames. Compare to my CCD
image shown below.
The image below represents my earler effort to image this object with a CCD camera. I used an ST10XME camera, with an AP 0.67x reducer, through a 12" Meade LX200R
telescope. I combined exposures of 45 minutes luminance with 12 minutes of red and green, and 18 minutes of blue.