This deep view of IC 5146, the Cocoon Nebula, reveals the complex network of interstellar dust and faint hydrogen emission surrounding this well-known star-forming region in Cygnus, approximately 2,500 light-years away.
The bright Cocoon Nebula appears on the right side of the image, at the end of Barnard 168, the prominent dark cloud extending across the field. With sufficiently deep exposure, however, the apparently empty background reveals itself to be filled with layers of illuminated and obscuring dust, together with extremely faint H-alpha emission extending across much of the region.
The image was acquired over seven nights from Foppolo, in the Italian Alps, at an altitude of approximately 1,650 meters, and represents the first light of MANTA, my new dual-telescope imaging system.
MANTA consists of two extensively modified 114/456 mm Newtonian telescopes, each reduced to approximately 342 mm at f/3 and equipped with a ZWO ASI2600MC Pro camera. Both optical systems operate simultaneously on a single mount, allowing two independent datasets to be collected during the same observing time.
Interestingly, such a long integration was never originally planned. IC 5146 was selected as a fixed target while testing and debugging the new system, deliberately keeping the astronomical target unchanged while other variables were progressively evaluated. Night after night, the data simply continued to accumulate.
The final image combines 37 h 15 min acquired with an Optolong L-Para filter and 39 h 35 min with an Optolong L-QEF, for a total integrated exposure of 76 h 50 min.
The two datasets were processed separately and subsequently combined. The H-alpha component extracted from the L-Para data through continuum subtraction was used to enhance the extremely faint hydrogen emission while preserving the broadband structures and colors of the surrounding dust.
What began as an engineering test therefore became, almost unintentionally, my deepest astronomical image to date.
Imaging: Gianmaria Veronese
Location: Foppolo, Bergamo, Italy — 1,650 m
Total integration: 76 h 50 min
Telescope: 2× modified 114/456 mm Newtonians + Starizona Nexus 0.75× — 342 mm f/3
Cameras: 2× ZWO ASI2600MC Pro
Filters: Optolong L-Para / L-QEF
Mount: ZWO AM5