Hi All,
A while between posts again, so I'm pleased to present an image in which I've been working on for a while. Data collection stalled a few times due to weather and other commitments. The inspiration to produce this image originally came from fellow member, Humayun (Octane) who
posted a similar scene back in July 2007 - most impressed by this, two years later I decided to focus my efforts.
So here's my rendition of the
Rho Ophiuchus Nebulae Complex.
Warning: large resolutions may take time to load.
About the target;
The Rho Ophiuchus Nebulae Complex is located in the constellation of Ophiuchus, and is perhaps one of the most colourful and intriguing areas of the night sky. It features, the red giant Antares, the Ophiuchi triple star surrounded in reflection nebulae (IC4604). In addition, present is a globular cluster (M4) with a dense star core accompanied by a the small cluster (NGC6144) and various segments of dark nebulae. The red-supergiant star Antares dominates the image and is surrounded by unusual yellow reflection nebulosity. Antares is approximately 700 light years away and is 10,000 times more luminous than our Sun. The sensational blue IC 4604 reflection nebula surrounding the Rho Ophiuchi triple star is intriguing feature of this complex. It is a result of interstellar dust that is illuminated by nearby stars. The red areas of this image are red emission nebulae that are created by hydrogen gas emitting light. The dark areas are not star void, but are dark nebula where thick dust clouds are obscuring background stars.
A few words on the image;
The image is an eight panel LRGB mosaic covering approx 7.2 x 9.5 degrees (two hours data per panel). While the FSQ has a spacious FOV, it simply doesn't do the area justice as a single frame. I kept the overlap percentage relatively large - TheSky data acquisition plan is attached for reference. Post registration, I stitched the luminance frames together, then proceeded to work on the RGB. The two were then introduced. Could have spent more time on stitching as some frames didn't blend so well. Luminance is typically easy, chrominance is a different story. The RGB data was particularly complex to work on with due subtle colour shifts and matching challenges. I originally thought the brightening toward the bottom right of the image was a gradient until I realised that its the natural glow of the galactic plane. A heavily DDP stretched and saturated RGB layer provide the vibrant hues notorious of the region. Not much else to add, processing was similar to the
MW9 mosaic so you can read up on other aspects of the workflow if desired. The presented full resolution image has been reduced in size by 50%. The original is simply too large for web production without introducing jpeg compression artefacts.
Certainly not my best that's for sure - poor conditions while acquiring some of the green filtered subs has resulted in background hues in areas which have been difficult to chase, and maintain colour fidelity across the panels, overall its a mess IMO and I'm tiring of bright star reflections that the Custom Scientific filters deliver with this set up, so have a set Astrodon GenII's coming shortly.
A big shout-out to Bert (avandonk) who provided the scaffold image in which I utilised to correct frame rotation, ensuring optimal alignment of the panels - the 300mm lens delivers a lovely flat wide field. Much appreciated, thanks!
Anyway, enjoy it for what its worth!
Cheers
that is something so awesome I'm star struck, 
