NGC 6559 is part of a beautiful collection of emission nebula and  reflection nebula in the constellation of Sagittarius.  NGC 6559 is located just one degree east of M8 (the Lagoon Nebula) and is probably part of the same large nebulous complex and star forming region (the faint edge of M8 can be seen in the top center of the top image). NGC 6559 is the brightest patch of emission nebulosity in the top image and contains patches of red emission nebulae as well as blue reflection nebulae and dark opaque nebulae.  Dark Nebula B 303, can easily be seen in the top and bottom image (left side) as a dark serpentine structure snaking thru the center of the complex.

Another curiosity in this image is the small bright circular patch of nebulosity noted as GN 18.06.6.01 (GN stands for galactic nebula - i.e. regions of nebula within our own galaxy).  No alternate designations were given so it is not in the Sharpless Catalogue or any other catalogue.

BOTTOM IMAGE

The bottom image shows a much wider field of view (slightly less than 3 degrees wide x 2 degrees high) with "north up" so that the image appears as it is oriented when looking towards the southern horizon.  NGC 6559 is located on the left side of this image as it appears in the sky with the large emission nebula M8, the Lagoon Nebula, to its west in the bottom center of the image.  To the northwest (top right corner) is the famous combination emission and refection nebula M20, aka the Trifid Nebula. Since we are looking along the axis of our Milky Way numerous stars fill the image frame except where their light is blocked out by areas of dark nebula in the foreground.

 IMAGE DETAILS (both images):

• Date & Location:  June 27th, 2012 - Bernville, PA

• Weather:  Calm winds, temperature range 55F to 50F

• Sky Conditions:  Clear with some patchy clouds and average transparency. 

• SQM-L: 20.45 start - 20.50 finish

• Optics:  TeleVue NP101is Refractor with focal reducer (432mm f4.3)

• Filter:  Hutech IDAS-LPS (Light Pollution Suppression)

• Mount:  AstroPhysics AP900GTO

• Guiding:  Orion SSAG @5 seconds

• Camera:  Canon T1i (500d) Hap Griffin modified - Baader UV/IR

• Exposure:  Top Image: 1 x 4min, 4 x 8 min @ ISO800 - 36 minutes total exposure

•                    Bottom Image: 7 x 8min @ ISO800 - 56 minutes total exposure

• Calibration Frames:  Master Dark & Bias 50F

• Processing:  Images Plus 4.50b, PS CS6, GradientXTerminator, NIK filter tools 

• Comments:  Good skies except for occasional patchy mid-level clouds that limited exposures captured.  In hindsight it would have been better to obtain more images on a multi-night shoot in order to resolve better detail.