Celestial hemisphere:  Southern  ·  Constellation: Ophiuchus (Oph)  ·  Contains:  Extremely wide field

Image of the day 08/14/2018

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The Scorpion's Head - A Panorama of Stars and Nebulae, Gabriel R. Santos (grsotnas)
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The Scorpion's Head - A Panorama of Stars and Nebulae

Image of the day 08/14/2018

Getting plate-solving status, please wait...
The Scorpion's Head - A Panorama of Stars and Nebulae, Gabriel R. Santos (grsotnas)
Powered byPixInsight

The Scorpion's Head - A Panorama of Stars and Nebulae

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Description

This image features a giant field in the sky – over 30 degrees (or 60 full moons) across, in the region of the Scorpion’s Head! The colorful Rho Ophiuchi region, some 460 light years away, including the bright orange star Antares is visible just right of center, and the nebula Sharpless 1 (Sh2-1) appears on bottom right, near Pi Scorpii; and in the top right the Blue Horsehead. Antares - Rho Ophiuchi cloud complex is notable for its colorful vistas – blue reflection nebulae and red emission nebulae; along with dark nebulae and the yellow glow illuminated by Antares. The region also features the globulars clusters M4 – discovered in 1745 and catalogued by Messier in 1764 – which is located ~7200 light years away; and the smaller M80 as well. The red nebulosity emanates from nebulas glowing in the light of exited hydrogen gas, while blue marks interstellar dust reflecting the light of bright young stars. Notably the Blue Horsehead Nebula (IC 4592), located some 400 light-years away. Its main part is in a reflection nebula within a molecular cloud complex. Reflection nebulas are made up of very fine dust that normally appears dark but can look quite blue when reflecting the light of energetic nearby stars. In this case, the source of much of the reflected light is a star at the eye of the horse, Nu Scorpii. A second smaller reflection nebula, IC 4601, is visible as well. [Paragraph adapted from APOD]

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This mosaic has an interesting story behind it: it was captured on 3 different nights, from two distinct locations 1000km away from each other! The 1st three panels were captured on 08/07 from MG, and the remaining panels were captured a few days later at EBA (Encontro Brasileiro de Astrofotografia). Some frames had some clouds or cirrus that I didn’t notice until processing. But I had to use them, which negatively impacted normalization and SNR of the frames.

The panels feature different exposure times, ranging from 6 to 18 subframes per panel. The end result is a ~4-hour total exposure. Processing was a little difficult, consisting on: Pre-Processing, Mosaicking and Background Calibration in APP; Post-Processing in PS/Nik/HLVG/Fitswork/LR.

The result is a whopping 117 megapixels (~13000 x 9000px). The image posted here is a 33% resize. I am looking for a way to share the larger file - any suggestions are welcome! This is the 1st image in which I apply the new labelling - what is your opinion on the label being stamped in the full image? Please share your thoughts in the comments!

Constructive criticism, comments and suggestions are more than welcome in the comments section. Thank you for taking your time to look at this image.

Taken from Rural and Dark Skies (Bortle 2-3-4; SQM ~21.7-21.4*calculated), from MG and GO, Brazil.

Date and Time: July 08, 11 and 12, 2018

Camera: Canon EOS T5 (modded), at ISO 800

Lens: Samyang 135mm f/2.0, operated at f/2.4

Mount: Sky-Watcher HEQ5, tracking, guided

Guiding: Starguider 50mm Guidescope + ASI120mm + PHD2; ~1-1.4" RMS

Exposure Detail: 9 panel mosaic; each 10 to 18x120s; Total 115x120s or 230 minutes

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The Scorpion's Head - A Panorama of Stars and Nebulae, Gabriel R. Santos (grsotnas)