RCW 114 is a beautiful, rarely imaged cosmic cloud toward the southern constellation Ara, here presented in its cosmic context. It spans nearly 7 degrees or 14 full moons. This image field is a whopping 30 full moons across! RCW 114 has been recognized as a supernova remnant. Its extensive filaments of emission are produced as the still expanding shockwave from the death explosion of a massive star sweeps up the surrounding interstellar medium. It is estimated to be 600 light-years away, some 100 light-years in diameter [1] A spinning neutron star or pulsar has recently been identified as the remains of the collapsed stellar core. [1]

The RCW catalogue features 182 HII regions in the southern sky, compiled by Rodgers, Campbell e Whiteoak in 1959-1960. It featured 78 panels, each 20min Ha and 7min yellow plates, covering 194 degrees long and a maximum of 30 wide. In its original publication [2], the authors wrote some interesting techniques used to complete the survey “In 1957, a survey programme of the Southern Milky Way for the detection of Ha regions was initiated at Mount Stromlo Observatory by Professor B. J. Bok. This programme was carried out with a Meinel-Pearson 8-inch f/1 flat field Schmidt which was mounted as a counterweight to the 6-inch Farnham refractor used as the guiding telescope. […] The majority of the plates were obtained by Rodgers, the remainder by Campbell. […]” About RCW 114, it is written: “Ring of emission 50' wide.” [2]

I strongly recommend checking the original work at [2]. It is a truly remarkabl effort employed in the making of such surveys, in a time in which imaging was analog: no electronics nor autoguiding! Just imaging eye-guiding a 78-panel survey, with a total exposure time of 35 hours [78 panels *(20+7)min] !

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Differently from the original RCW publication, my image was much more digital! What great times we live in! The exposures were captured using mainly photographic equipment atop a guided equatorial mount!

This image presented a great surprise to me! Whilst processing, I noticed a strangely green star in the upper left corner. That was unusual! A little investigation solved the mystery – it was not a star, but a comet! It was in fact C/2016 M1 (PANSTARRS), a comet that was visible. By accident and without knowing the coordinates of this little comet, it was framed in my image, and ended up captured on camera!

Processing was a challenge. My color camera, despite being modded, struggles to define the Ha filaments. The starfield is extremely strong, and the nebula extremely faint! To better capture the nebulosity, a mono H-alpha narrowband system would be preferable. Nonetheless, I was pleased to see the nebula faintly pop out in a beautiful Milky Way field, given the equipment and the relatively short integration of 1h/panel. I especially recommend checking the inspirational images by Andrew Campbell, Stephan Küppers, or the absolutely jaw-draping John Gleason H-alpha mosaic! [3].

RCW114 may be below the horizon for northern imagers, but even amongst southern astrophotographers, this target is very rarely chased by amateurs… I just find it enchanting, and reminds me of the Veil Nebula!

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

Date and Time: July 7, 2018; ~20h [local UTC-3 time]

Location: MG, Brazil. Rural Skies (Bortle 3-4, SQM ~21.4*calculated)

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; ~1.3”

Exposure Detail: 2 panel mosaic, each 30x120s; Total 120 minutes

[1] APOD 2018/01/11; [2] A CATALOGUE OF Ha-EMISSION REGIONS IN THE SOUTHERN MILKY WAY A. W. Rodgers, C. T. Campbell andj. B. Whiteoak [online at adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1960MNRAS.121..103R ] [3] Campbell at astrobin.com/328424 | Küppers at sterntaucher.net | Gleason at astrobin.com/94334