<p>Subject: Orion sword mosaic -- 6 panels (includes existing M42 shot + existing HH shot + 4 others)  
</p><p>Image FOV = 6.62 degrees by 4.78 degrees (397 minutes by 287 minutes) -- approximate 
</p><p>Image Scale = 20 arc-second/pixel 
</p><p>Date: 2006/12/02, 2006/12/30, 2007/01/10, 2007/01/16, 2007/01/17, 2007/02/08, 2007/02/09, 2007/02/15, 2007/02/16  
</p><p>Exposure: 39x600s (M42 area) + 40x600s (Horsehead area) + 66x600s (rest) = 145x600s = 24h10m total exposure -- ISO800, f/4.8
</p><p>Filter: Baader 7nm H-alpha filter 
</p><p>Camera: Hutech-modified Canon 30D 
</p><p>Telescope: SV80S 80mm f/6 + TV TRF-2008 0.8X reducer/flattener = 384mm FL, f/4.8 
</p><p>Mount: Losmandy G-11
</p><p>Guiding: ST-402 autoguider and SV66 guidescope. MaximDL autoguiding software using 1-second guide exposures 
</p><p>Processing: Raw conversion and calibration with ImagesPlus (dark and bias frames only, no flat frames); Aligning and combining with Registar; Initial levels adjustment (gamma=2.5) and cropping in PhotoShop CS and CS4.  Then mosaicing with AutoPano Pro, more levels adjustment, downsampling, and JPEG conversion with PhotoShop CS4. 
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Remarks: temperatures at end:  25F, 24F, 19F, 25F, 27F, 23F, 23F, 20F, 25F.  Taken from a light-polluted location (perhaps 20.25 SQM reading, average)
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/45032885@N04">s58y</a>
CC BY 2.0
<p><a rel="nofollow" class="external text" href="https://www.flickr.com/photos/s58y/4459232226/">Orion Sword Mosaic</a>
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<ul><li>Uploaded by <a href="//commons.wikimedia.org/wiki/User:ComputerHotline" title="User:ComputerHotline">ComputerHotline</a></li></ul>