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6. NGC884, NGC869, Double Cluster
Notes: This is our first attempt at imaging a star cluster, and we (i.e. Gary) made a number of blunders. Probably the worst is overexposing the images. Two minutes is too long for ISO 1600. The histogram should be checked on a trial exposure before setting the gain and executing the exposure schedule. We used the darks from the previous session (5), which were exposed for a much longer period. That might have introduced the noise that is apparent in red flecks and a reddish background in the originals. We kept the focus from the previous night, which theoretically should be OK. It's not clear from the images that there is a problem with the focus, but it's possible that small changes occurred. Given the messy process, perhaps it's surprising that the final product is viewable. Zoom in/out with ⌘↑(+/-) (Mac), ctrl (+/-) (PC).