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Contains:  M 13, Great Cluster in Hercules, NGC 6205
Getting plate-solving status, please wait...

M13 - The Great Globular Cluster in Hercules

Technical card

Resolution: 4554x3243

Dates:March 31, 2018April 7, 2018

Blue: 10x240" -20C bin 1x1
Green: 10x240" -20C bin 1x1
Luminance: 52x180" -20C bin 1x1
Red: 10x240" -20C bin 1x1

Integration: 4.6 hours

Darks: ~50

Flats: ~50

Bias: ~256

Avg. Moon age: 18.09 days

Avg. Moon phase: 78.84%

Bortle Dark-Sky Scale: 5.00 job: 2019059

RA center: 250.421 degrees

DEC center: 36.459 degrees

Pixel scale: 0.526 arcsec/pixel

Orientation: 92.137 degrees

Field radius: 0.409 degrees


Often referred to as the finest globular cluster in the northern sky, Messier 13 is likely home to hundreds of thousands of stars. Stars in globulars such as these can be compacted into tight little neighborhoods, with typical separations of only a light year (less quarter the distance we are from our closest neighbor). In fact, in the core, star spacings could be significantly more cramped. They typically consist of large older stars of roughly the same age, indicating they were spawned by a similar common mechanism. Though uncommon, the tight spacing does lead to occasional star mergers in which the resultant star differs significantly from the rest of the population.

Globulars are typically satellites of a host galaxy and this one is no exception. This globular sits over 20,000 light years distant and outside the disk of the Milky Way. Measuring close to 200 light years wide it is one of the largest in apparent size for us on Earth.

I was able to finish this one off though the data was shot under less-than-stellar conditions and under direct moonlight. It is less integration than I would normally put into an image, but you have to take what you can get, I suppose. One thing good about shooting globulars is that they are not affected as much by the moon, so that was what led me to capture it when I did. I'm still really hoping the weather takes a turn toward Spring!




Jason Guenzel
License: None (All rights reserved)

Sky plot

Sky plot


M13 - The Great Globular Cluster in Hercules, 


            Jason Guenzel