Derby and District Astronomical Society
IC 59 and IC 63
Emission and Reflection Nebulae in Cassiopeia
RA 00h 56m 42s Dec +61° 04' 00" (IC 59)
RA 00h 59m 30s Dec +60° 49' 00" (IC 63)
[IC Index]
Adrian Brown took the following image of the combined emission and reflection nebulae IC 59 and IC 63 in Cassiopeia during September 2006. These nebulas lie close to the star Gamma Cassiopeiae (visible at lower left). The emission nebulae are composed of ionised hydrogen and appear red in this image. The reflection nebulae are due to starlight scattered off dust clouds and appear blue. Adrian used an ATK16HR camera through an 80ED refractor to take the image. In his own words: "They proved to be a difficult target and needed a lot of colour exposures to produce a good signal to noise ratio. This image could be described as a HaRGB as I used an Astronomik 6nm Hydrogen-Alpha filter, with the camera running at its highest resolution, to provide the fine detail luminance image. For the colour data, I used Astronomik RGB filters and the camera was running in 2x2 Binned mode which halves the resolution but increases the sensitivity four fold. Taking the colour data at a lower resolution and then combining it with the high resolution luminance data is a useful trick to speed up the imaging process as a 5 minute exposure binned 2x2 is equivalent to a 20 minute exposure at the camera's full resolution. The total exposure times were 16 x 30 minutes H-alpha (Bin 1x1) , 25 x 5 minutes Red (Bin 2x2), 13 x 5 minutes Green (Bin 2x2) and 31 x 5 minutes Blue (Bin 2x2). The exposures were calibrated and combined in Maxim DL and processed in Photoshop. Photoshop processing consisted of levels and curves, smoothing noise with a Gaussian blur filter, blending 50% hydrogen-alpha data into the red channel to produce a deeper red colour (without this, IC63 came out as a rather anaemic salmon pink colour!), blending the low res colour data with the hi res hydrogen-alpha data to produce the final image". Image Credit: Adrian Brown.
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