Cygnus constellation mosaic


In an attempt to capture a large swath of sky at high resolution, I've spent the summer capturing 28 panels (7 across, 4 down) of the constellation Cygnus the Swan (aka the Northern Cross).

Shot through a narrowband hydrogen-alpha filter, this field shows off an entertaining area of our Milky Way galaxy, full of glowing hydrogen gas and dark dust lanes ... in fact the gas and dust almost dwarf the stars themselves.

The area includes several interesting nebulae, including the North America Nebula and Pelican Nebula at upper left, the Butterfly Nebula, at center right, and the small but fascinating Crescent Nebula at far lower right. Running down the center of the scene is a dark swath called the Northern Coal Sack, a virtual river of dust and gas that obscures many of the stars behind it.

This region covers approximately 12x12 degrees of the sky ... for reference, this is a little bit larger than the size of your palm held at arm's length. North is up.


This was a significant effort ... averaging 2.5 hours of exposure per panel, this image represents over 70 hours of exposure time (selected from over 100 hours of data, as some images were rejected for poor quality).

Captured at 328mm focal length (f3.9), with a small pixel size (5.4u), it has a sampling rate of 3.39 arc-seconds/pixel. I believe this a relatively high resolution image, at least relative to most large amateur astro-mosaics.

Telescope = Takahashi FSQ 85 EDX with .73 reducer (f/3.39)
Camera = QSI 583 wsg
Mount = SkyWatcher EQ6 Pro
Software = capture and stacking in MaximDL, alignment and mosaic in Autopano Pro, processing in PS CS5
Exposure (minutes) = average 160m / panel, 28 panels, over 70h total
Date = June-August 2012