File:IC1805 -- H-alpha + RGB.jpg

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IC1805_--_H-alpha_+_RGB.jpg(800 × 549 pixels, file size: 192 kilobytes, MIME type: image/jpeg)

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This file is licensed to s58y under the Creative Commons Attribution 2.0 Generic license.

Subject: IC1805 -- Heart Nebula (RGB + H-alpha)

Image FOV = 2 degrees 55 minutes by 2 degrees (175 minutes by 120 minutes)

Image Scale = 7.5 arc-second/pixel

Location: near Halcottsville, NY

Exposure: 26 x 10 minutes H-alpha plus 13 x 10 minutes RGB = 6h30m total exposure, ISO800, f/4.8

Filter: Baader 7nm H-alpha filter (H-alpha), IDAS LP filter (RGB)

Camera: Hutech-modified Canon 30D

Telescope: SV80S 80mm f/6 + TV TRF-2008 0.8X reducer/flattener = 384mm FL, f/4.8

Mount: Astro-Physics AP900

Guiding: ST-402 autoguider and SV66 guidescope. MaximDL autoguiding software using 6-second guide exposures

Processing: Raw conversion and calibration with ImagesPlus (dark and bias frames only, no flat frames); Aligning and combing with Registar; Levels adjustment on RGB and H-alpha image. Then: Red channel = 1/3 * RGB_ red + 2/3 * max(gamma(RGB_red, .75), Ha_red) Green channel = 1/3 * RGB_ green + 2/3 * max(gamma(RGB_green, .75), 1/3 * Ha_red/5) Blue channel = 1/3 * RGB_ blue + 2/3 * max(gamma(RGB_blue, .75), 1/3 * Ha_red/5) Then, more levels, cropping/resizing, JPEG conversion with Photoshop CS.

Remarks: Temperature at end: 22F (H-alpha), 26F (RGB); SQM readings: 21.3 to 21.49; No noise reduction.

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current12:48, 21 February 2018Thumbnail for version as of 12:48, 21 February 2018800 × 549 (192 kilobytes)DavidB4 (Talk | contribs)Copied from https://commons.wikimedia.org/wiki/File:IC1805_--_H-alpha_%2B_RGB.jpg <br/> This file is licensed to [https://www.flickr.com/people/45032885@N04 s58y] under the Creative Commons Attribution 2.0 Generic license.<br/> Subject: IC1805 -- Hear...
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