Messier 101, nicknamed the Pinwheel Galaxy, is a face-on spiral galaxy about 21 million light years from Earth in the constellation Ursa Major. It was discovered by Pierre Mechain in 1781. He communicated the discovery to Charles Messier who verified its position and included it in his Catalogue as one of its final entries.
Notice that the apiral arms are not symmetrical around the galaxy core. Also look closely for the faint blue star-forming regions extending far beyond the ends of the arms.
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| Processing |
• With PixInsight: ☞ Calibrate, star-align, and integrate subframes ☞ Background neutralization ☞ Process for high-dynamic range • Final tweaking in Photoshop CS6 |
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• 2020: February 22 & 23 • 2021: February 20 • 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