M29
NGC 6913, Cooling Tower
45’ x 29’ | 0.3”/px | 8992 × 5892 px | full resolution
Cygnus
RA 20h 23m Dec +38° 29’ | 180°
Messier 29, also known as the Cooling Tower Cluster, is a quite small, bright open cluster of stars just south of the central bright star Gamma Cygni in the constellation Cygnus. It was discovered by Charles Messier in 1764. M29 is well within the several degrees of the arms and bulge of the Milky Way. Its age is estimated at 10 million years, as its five hottest stars are all giants of spectral class B0. The four brightest stars form a quadrilateral, and another set a small triangle just north of the northernmost of the four. It is often known as the "cooling tower" due to its resemblance to the hyperboloid-shaped structures. A few fainter stars are around them, but the cluster appears quite isolated.
source: Wikipedia
Data Acquisition
Data was collected over 8 nights during the month of May 2025, using a 14” reflector telescope with full-frame camera at the remote observatory in Spain. Data was gathered using standard LRGB filters. As a simple target it was added to the observation schedule to fill in some gaps in the later parts of the night, when other observed targets had gone too low. A total of 6 hours of data was finally combined to create the final image.
Location Remote hosting facility IC Astronomy in Oria, Spain (37°N 2°W)
Sessions
Frames
Equipment
Telescope
Mount
Camera
Filters
Guiding
Accessoires
Software
Planewave CDK14 (2563mm @ f/7.2), Optec Gemini Rotating focuser
10Micron GM2000HPS, custom pier
Moravian C3-61000 Pro (full frame), cooled to -10 ºC
Chroma 2” LRGB unmounted, Moravian filterwheel L, 7-position
Unguided
Compulab Tensor I-22, Dragonfly, Pegasus Ultimate Powerbox v2
Voyager Advanced, Viking, Mountwizzard4, Astroplanner, PixInsight 1.9.3
Processing
All processing was done in Pixsinsight unless stated otherwise. Default features were enhanced using scripts and tools from RC-Astro, SetiAstro, GraXpert, CosmicPhotons and others. Images were calibrated using 50 Darks, 50 Flats, and 50 Flat-Darks, registered and integrated using WeightedBatchPreProcessing (WBPP). The processing workflow diagram below outlines the steps taken to create the final image.
The blue channel had a star trail remaining which had not been completely removed during pixel rejection. In order to remove this, the Blemish Blaster from SetiAstro was used. This tool has a special function for star trails. The zoom-function in combination with the Cmd-drag functionality did not work very well to precisely remove a large feature that runs all across the frame. But doing it in a couple of smaller steps worked well.
The bright stars had some halos around them that showed very light hints of magenta and green. These hues were removed using SCNR on de inverted and on the regular image respectively.
Towards the end a final crop was applied. Normally I would crop in much tighter, but with these open clusters it is often nicer to show them in wider star-field. It makes the object stand out better in its environment and is easier recognised as an object. The nebula is kept ‘up-side-down’, so the top of the image is pointing South. Somehow this felt a bit better from a composition standpoint with some gaps in the star field in the right half of the image.
The rest of the processing followed largely a standard processing workflow as is shown below.
Processing workflow (click to enlarge)
This image has been published on Astrobin.
