M13 is a beautiful globular star cluster located in the constellation Hercules. It is about 25,100 light years away (one-quarter of the diameter of our galaxy), and is about 168 light years across. Recent estimates say it is 14 to 16 billion years old.
This cluster was discovered by the British astronomer Edmund Halley in 1714, and catalogued by Charles Messier in 1764. M13 contains at least 300,000 stars; some observers believe it contains nearly a million.
Notice the faint galaxy NGC6267 (magnitude 13.3) near the top of the photo, toward the left. Even-fainter galaxy IC4617 (magnitude 15.2) can be seen next to a star about 40% of the distance from the top of the cluster toward NGC6267.
| Exposure |
• 6⅔ hours (131 x 3 min.) @ -20°C |
| Processing |
• Calibration, registeraton, and stretching with PixInsight • Final tweaking in Photoshop CS6 |
| Date and Location |
•
May 13 & 14, 2021 • Louisa County, Virginia, USA |
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Equipment |
• TMB-130SS APO refractor @ f/7 on an A-P 1200 mount • ZWO ASI-1600MC Pro color camera • Guided with an ST-402 camera on a 60mm f/5 scope • Imaging and autoguiding with MaxIm DL 6.20 • Automated image acquisition with ACP Observatory Control |
Updated May 23, 2023