22 Oct 2026-------------- Noirlab 2625

 

Before Rubin Observatory’s First Look event, its engineering camera captured exquisite details of star formation taking place in the Seagull Nebula

 

Two years ago this month, NSF–DOE Vera C. Rubin Observatory’s engineering test camera, named the LSST Commissioning Camera (ComCam), began capturing images of the sky to prepare for the revolutionary Legacy Survey of Space and Time, which began earlier this year. This image featuring the head of the Seagull Nebula was one of many ComCam images that led to the success of Rubin First Look and helped to document the observatory’s excellent performance.

Active star formation populates this image of the Seagull Nebula taken in Fall 2024 by NSF–DOE Vera C. Rubin Observatory’s engineering test camera, known as the Commissioning Camera (ComCam). This image is being released today in recognition of the two-year anniversary of the beginning of engineering testing with ComCam.

ComCam’s work was an important step towards the ongoing Legacy Survey of Space and Time (LSST). Collecting the data for this Seagull Nebula image provided an opportunity to test Rubin’s hardware and software systems, as well as the image processing pipelines that would later be used with the much larger images from the LSST Camera.

With a mosaic of nine CCD sensors and a total of 144 megapixels, ComCam covers an area in the sky about twice that of the full Moon. Over the seven-week ComCam engineering test campaign, from 24 October to 11 December 2024, approximately 16,000 exposures were acquired. Within the data collected is this image featuring IC 2177, a region recognizable as the head of the Seagull Nebula.

Rubin Observatory is a joint initiative of the U.S. National Science Foundation (NSF) and the U.S. Department of Energy’s Office of Science (DOE/SC). Rubin is operated jointly by NSF NOIRLab and SLAC National Accelerator Laboratory. 

Located about 3700 light-years away from Earth, between the constellations of Monoceros (The Unicorn) and Canis Major (The Great Dog), lie three expansive clouds of gas. These clouds, Sharpless 2-292, Sharpless 2-296, and Sharpless 2-297, form a shape that looks like a seagull in flight. Sharpless 2-292 represents the head of the nebulous bird and is pictured here.

The spectacular pink and blue colors of this nebula are caused by the rich star formation within it. When stars are born in molecular clouds, they emit ultraviolet radiation hot enough to ionize, or energize, the surrounding hydrogen gas and cause it to glow. The pressure of this radiation sweeps away light-obscuring material, such as dust, and makes the glowing hydrogen gas visible. In this image these regions appear pink. The contrasting blue haze is composed of dust particles reflecting the light of the other young stars in the area.

Sharpless 2-292 is a cloud of ionized hydrogen gas, known as an H II region, within IC 2177. The source of Sharpless 2-292 is HD 53367, a triple star system of massive young stars that sits at the top of the dark, jagged ridge in this image where it represents the Seagull’s blue eye.

With just 144 megapixels, ComCam is much smaller than the 3200-megapixel LSST Camera, which is now mounted on the Simonyi Survey Telescope and executing the Legacy Survey of Space and Time (LSST). LSSTCam’s field of view is 21 times larger than ComCam’s, which enables it to capture images of the entire southern hemisphere sky every 3–4 nights. Until LSST collects more data, this image is the deepest and sharpest view of this region.

This ComCam image of the Seagull Nebula gave Rubin’s image processing team early experience working with the complex structures found in star-forming regions. That experience helped the team identify and solve processing challenges that would also arise with the much larger LSST Camera images, including the Trifid and Lagoon Nebulae, one of the Rubin First Look images released in June 2025. 

With its job on the telescope completed, ComCam now serves as a test stand in the summit clean room, supporting LSST Camera software testing and the regular cycling of spare vacuum pumps and refrigeration compressors to keep them in good working order. Although ComCam is no longer taking images of the sky, it continues to play an important role in supporting Rubin behind the scenes as the Legacy Survey of Space and Time gets underway.