Open cluster M11


The bright open cluster Messier 11 (NGC 6705) in Scutum, the "Wild Duck" cluster, shown from a 30-second red-light exposure (through clouds) with a Tektronix 2048x2048 CCD at the prime focus of the 4-meter Mayall telescope of Kitt Peak National Observatory. North is at the top and east to the left, for direct comparison with a chart or eyepiece view. The image has been block-averaged to 512x512 for this presentation, which uses a logarithmic intensity transformation to preserve information across a wide dynamic range. The field is 14.3 arcminutes square. Even with this short exposure, some of the brighter stars saturated the CCD strongly enough for some of the charge to bleed along columns of the chip, accounting for the vertical bright streaks from their centers.

When well seen (not always the case with out typical sky conditions in Alabama), I have long found this one of the most impressive of open clusters for its richness and compactness - it stands out unusually well against even the rich star cloud in Scutum. Check it out!



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