NGC3521 in Leo


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Exposure Data: 3/18/2004.  LRGB: 40x3m, 10x3m, 10x3m, 10x3m. RGB binned 2x2. -20C, .59 arc-sec./pixel.
Processing: Acquired via Sequencer II and CCDSoft, reduced, aligned and combined in Mira, L 30xRL in AIP4WIN, DDP in Maxim, LLRGB combine, curves, levels and other processing in Photoshop.
Optical System: 14.5 Ritchey-Chretien RCOS Truss @ F/6.4, ST-10XME NABG/CFW-8A CCD camera, Paramount ME.  AstroDon filters with IR-filtered L.  Unguided and dithered 3 arc-sec.
Comments: Seeing around 3 arc-sec, deconvolved to 2.4 arc-sec.  Acquired using an experimental version of Sequencer II, which included an automatic meridian flip and unguided dithering.  Actual exposure sequence was 5R, 5G, 5B, 40L, 5B, 5G, 5R.  The meridian flip occurred around the middle of the L sequence.